997.2 3.8 Engine Failure
03-01-2019, 10:08 AM
#511
I don't know what Jake does when he raises the capacity to 4 litre - but there are several different ways we can do it over in the UK.
Generally if it is a 3.6 the result is more torque but less peak BHP than if it starts out as a 3.8 (mainly because the valves in the 3.8 are about 2mm on average bigger in diameter and therefore breathe more air at high revs when the time available for each valve to be open is reduced).
We find as a rough guide that torque generally increases more than the capacity increase % but bhp is similar.
This is simply because if you were designing a 4.0 you would probably put bigger inlets and exhausts on it than std (although Jake may do just that?).
The irony is that most engines of this type are designed for more top end than any owner is ever likely to use and most owners spend more of their life driving between say 2500 and 6000 rpm and more often than not want to accelerate in the gear they are in (rather than down shift and thrash it). It is ironical because the acceleration of a vehicle is proportional to torque not BHP and even if you rev to peak revs before changing up a gear, the revs still drop down as you engage the next gear - so you are always driving though a rev band in which the average torque is m ore relevant than the peak BHP and increasing the torque lower down usually results in faster acceleration through the gears and more comfortable fast acceleration from lower revs without changing up.
In other words making an engine oversized, often results in a faster car that is easier to drive and reduces the need to rev it out which is often safer providing everything is running OK.
The trouble with the M96/7 oversized engines is that increasing torque at low revs is more likely to make them score unless the bores are also changed to Nikasil (which ours are).
Usually a 3.6 to 3.9 or 3.4 to 3.7 M96/7 increases torque about 15% without changing anything else and raises peak BHP by nearer 8%.
Increasing the capacity too much can result in peak BHP being hardly any different but increases in torque from even lower revs being even more dramatic (typical or our 3.2 Boxster to 3.7 which is much quicker but does not have a lot more bhp at peak revs).
Jakes 4.0 I am sure will be awesome.
Baz
Generally if it is a 3.6 the result is more torque but less peak BHP than if it starts out as a 3.8 (mainly because the valves in the 3.8 are about 2mm on average bigger in diameter and therefore breathe more air at high revs when the time available for each valve to be open is reduced).
We find as a rough guide that torque generally increases more than the capacity increase % but bhp is similar.
This is simply because if you were designing a 4.0 you would probably put bigger inlets and exhausts on it than std (although Jake may do just that?).
The irony is that most engines of this type are designed for more top end than any owner is ever likely to use and most owners spend more of their life driving between say 2500 and 6000 rpm and more often than not want to accelerate in the gear they are in (rather than down shift and thrash it). It is ironical because the acceleration of a vehicle is proportional to torque not BHP and even if you rev to peak revs before changing up a gear, the revs still drop down as you engage the next gear - so you are always driving though a rev band in which the average torque is m ore relevant than the peak BHP and increasing the torque lower down usually results in faster acceleration through the gears and more comfortable fast acceleration from lower revs without changing up.
In other words making an engine oversized, often results in a faster car that is easier to drive and reduces the need to rev it out which is often safer providing everything is running OK.
The trouble with the M96/7 oversized engines is that increasing torque at low revs is more likely to make them score unless the bores are also changed to Nikasil (which ours are).
Usually a 3.6 to 3.9 or 3.4 to 3.7 M96/7 increases torque about 15% without changing anything else and raises peak BHP by nearer 8%.
Increasing the capacity too much can result in peak BHP being hardly any different but increases in torque from even lower revs being even more dramatic (typical or our 3.2 Boxster to 3.7 which is much quicker but does not have a lot more bhp at peak revs).
Jakes 4.0 I am sure will be awesome.
Baz
03-01-2019, 12:20 PM
#512
Originally Posted by bazhart
I don't know what Jake does when he raises the capacity to 4 litre - but there are several different ways we can do it over in the UK.
Generally if it is a 3.6 the result is more torque but less peak BHP than if it starts out as a 3.8 (mainly because the valves in the 3.8 are about 2mm on average bigger in diameter and therefore breathe more air at high revs when the time available for each valve to be open is reduced).
We find as a rough guide that torque generally increases more than the capacity increase % but bhp is similar.
This is simply because if you were designing a 4.0 you would probably put bigger inlets and exhausts on it than std (although Jake may do just that?).
The irony is that most engines of this type are designed for more top end than any owner is ever likely to use and most owners spend more of their life driving between say 2500 and 6000 rpm and more often than not want to accelerate in the gear they are in (rather than down shift and thrash it). It is ironical because the acceleration of a vehicle is proportional to torque not BHP and even if you rev to peak revs before changing up a gear, the revs still drop down as you engage the next gear - so you are always driving though a rev band in which the average torque is m ore relevant than the peak BHP and increasing the torque lower down usually results in faster acceleration through the gears and more comfortable fast acceleration from lower revs without changing up.
In other words making an engine oversized, often results in a faster car that is easier to drive and reduces the need to rev it out which is often safer providing everything is running OK.
The trouble with the M96/7 oversized engines is that increasing torque at low revs is more likely to make them score unless the bores are also changed to Nikasil (which ours are).
Usually a 3.6 to 3.9 or 3.4 to 3.7 M96/7 increases torque about 15% without changing anything else and raises peak BHP by nearer 8%.
Increasing the capacity too much can result in peak BHP being hardly any different but increases in torque from even lower revs being even more dramatic (typical or our 3.2 Boxster to 3.7 which is much quicker but does not have a lot more bhp at peak revs).
Jakes 4.0 I am sure will be awesome.
Baz
Generally if it is a 3.6 the result is more torque but less peak BHP than if it starts out as a 3.8 (mainly because the valves in the 3.8 are about 2mm on average bigger in diameter and therefore breathe more air at high revs when the time available for each valve to be open is reduced).
We find as a rough guide that torque generally increases more than the capacity increase % but bhp is similar.
This is simply because if you were designing a 4.0 you would probably put bigger inlets and exhausts on it than std (although Jake may do just that?).
The irony is that most engines of this type are designed for more top end than any owner is ever likely to use and most owners spend more of their life driving between say 2500 and 6000 rpm and more often than not want to accelerate in the gear they are in (rather than down shift and thrash it). It is ironical because the acceleration of a vehicle is proportional to torque not BHP and even if you rev to peak revs before changing up a gear, the revs still drop down as you engage the next gear - so you are always driving though a rev band in which the average torque is m ore relevant than the peak BHP and increasing the torque lower down usually results in faster acceleration through the gears and more comfortable fast acceleration from lower revs without changing up.
In other words making an engine oversized, often results in a faster car that is easier to drive and reduces the need to rev it out which is often safer providing everything is running OK.
The trouble with the M96/7 oversized engines is that increasing torque at low revs is more likely to make them score unless the bores are also changed to Nikasil (which ours are).
Usually a 3.6 to 3.9 or 3.4 to 3.7 M96/7 increases torque about 15% without changing anything else and raises peak BHP by nearer 8%.
Increasing the capacity too much can result in peak BHP being hardly any different but increases in torque from even lower revs being even more dramatic (typical or our 3.2 Boxster to 3.7 which is much quicker but does not have a lot more bhp at peak revs).
Jakes 4.0 I am sure will be awesome.
Baz
So is it unreasonable to expect to be able to build an 08 3.8 to get roughly 450hp?
This is what my goal is long term for my car. But don't know if it's even feasible....
Cw
03-01-2019, 12:23 PM
#513
RL Community Team
Rennlist Member
Rennlist Member
03-01-2019, 03:14 PM
#515
Originally Posted by Sneaky Pete
With my FSI 4.0 I'm about 410-ish up top (not at the wheels) with all the add ons. I would agree with the above statement.
Cw
03-01-2019, 03:42 PM
#516
Wow took me 2 days to read this whole thread on my free time lol Really sorry to the OP that had this engine failure and glad you're sorting it and moving on. I was browsing on youtube and came across this video that explains what direct injections are and how to prevent damages that are associated with it. Some of the preventatives include cleaning your injectors and using the right oil, the same things that the experts in here have mentioned. I highly recommend you guys take the time to watch it.
*please note I am in no way affiliated with this video, just thought it might give a better understanding of direct injections for some folks.
*please note I am in no way affiliated with this video, just thought it might give a better understanding of direct injections for some folks.
Last edited by Vincent713; 03-01-2019 at 04:35 PM.
03-01-2019, 04:02 PM
#517
Originally Posted by Vincent713
Wow took me 2 days to read this whole thread on my free time lol Really sorry to the OP that had this engine failure and glad you're sorting it and moving on. I was browsing on youtube and came across this video that explains what direct injections are and how to prevent damages that are associated with it. Some of the preventatives include cleaning your injectors and using the right oil, the same things that the experts in here have mentioned. I highly recommend you guys take the time to watch it.
Last edited by cwheeler; 03-01-2019 at 04:29 PM.
03-01-2019, 04:25 PM
#518
Rennlist Member
Great video. Thanks Vincent713
03-01-2019, 05:09 PM
#519
LSPI in DFI engines
Wow took me 2 days to read this whole thread on my free time lol Really sorry to the OP that had this engine failure and glad you're sorting it and moving on. I was browsing on youtube and came across this video that explains what direct injections are and how to prevent damages that are associated with it. Some of the preventatives include cleaning your injectors and using the right oil, the same things that the experts in here have mentioned. I highly recommend you guys take the time to watch it.
*please note I am in no way affiliated with this video, just thought it might give a better understanding of direct injections for some folks.
*please note I am in no way affiliated with this video, just thought it might give a better understanding of direct injections for some folks.
Here's one just posted by Jake Raby on the topic of "low speed pre-iginition" or (LSPI). If you have the 9A1 DFI engine, you might want to watch this one.
The following users liked this post:
bentrod (12-26-2019)
03-01-2019, 06:48 PM
#520
Rennlist Member
Both interesting and informative videos. I'm hoping Jake or Baz can comment on what the condition of the intake ports and valves are in when they are tearing down the 9A1 engines they are seeing. How are the AOS' handling the oil and keeping the valve's clean. Is the design of the 9A1 superior to others that have horror stories written about them (read BMW and others).
03-02-2019, 03:46 AM
#521
Nordschleife Master
Wow took me 2 days to read this whole thread on my free time lol Really sorry to the OP that had this engine failure and glad you're sorting it and moving on. I was browsing on youtube and came across this video that explains what direct injections are and how to prevent damages that are associated with it. Some of the preventatives include cleaning your injectors and using the right oil, the same things that the experts in here have mentioned. I highly recommend you guys take the time to watch it.
*please note I am in no way affiliated with this video, just thought it might give a better understanding of direct injections for some folks.
https://www.youtube.com/watch?v=xrLNDgrIw3U
*please note I am in no way affiliated with this video, just thought it might give a better understanding of direct injections for some folks.
https://www.youtube.com/watch?v=xrLNDgrIw3U
03-02-2019, 04:43 AM
#522
I don't know what Jake does when he raises the capacity to 4 litre - but there are several different ways we can do it over in the UK.
Generally if it is a 3.6 the result is more torque but less peak BHP than if it starts out as a 3.8 (mainly because the valves in the 3.8 are about 2mm on average bigger in diameter and therefore breathe more air at high revs when the time available for each valve to be open is reduced).
We find as a rough guide that torque generally increases more than the capacity increase % but bhp is similar.
This is simply because if you were designing a 4.0 you would probably put bigger inlets and exhausts on it than std (although Jake may do just that?).
The irony is that most engines of this type are designed for more top end than any owner is ever likely to use and most owners spend more of their life driving between say 2500 and 6000 rpm and more often than not want to accelerate in the gear they are in (rather than down shift and thrash it). It is ironical because the acceleration of a vehicle is proportional to torque not BHP and even if you rev to peak revs before changing up a gear, the revs still drop down as you engage the next gear - so you are always driving though a rev band in which the average torque is m ore relevant than the peak BHP and increasing the torque lower down usually results in faster acceleration through the gears and more comfortable fast acceleration from lower revs without changing up.
In other words making an engine oversized, often results in a faster car that is easier to drive and reduces the need to rev it out which is often safer providing everything is running OK.
The trouble with the M96/7 oversized engines is that increasing torque at low revs is more likely to make them score unless the bores are also changed to Nikasil (which ours are).
Usually a 3.6 to 3.9 or 3.4 to 3.7 M96/7 increases torque about 15% without changing anything else and raises peak BHP by nearer 8%.
Increasing the capacity too much can result in peak BHP being hardly any different but increases in torque from even lower revs being even more dramatic (typical or our 3.2 Boxster to 3.7 which is much quicker but does not have a lot more bhp at peak revs).
Jakes 4.0 I am sure will be awesome.
Baz
Generally if it is a 3.6 the result is more torque but less peak BHP than if it starts out as a 3.8 (mainly because the valves in the 3.8 are about 2mm on average bigger in diameter and therefore breathe more air at high revs when the time available for each valve to be open is reduced).
We find as a rough guide that torque generally increases more than the capacity increase % but bhp is similar.
This is simply because if you were designing a 4.0 you would probably put bigger inlets and exhausts on it than std (although Jake may do just that?).
The irony is that most engines of this type are designed for more top end than any owner is ever likely to use and most owners spend more of their life driving between say 2500 and 6000 rpm and more often than not want to accelerate in the gear they are in (rather than down shift and thrash it). It is ironical because the acceleration of a vehicle is proportional to torque not BHP and even if you rev to peak revs before changing up a gear, the revs still drop down as you engage the next gear - so you are always driving though a rev band in which the average torque is m ore relevant than the peak BHP and increasing the torque lower down usually results in faster acceleration through the gears and more comfortable fast acceleration from lower revs without changing up.
In other words making an engine oversized, often results in a faster car that is easier to drive and reduces the need to rev it out which is often safer providing everything is running OK.
The trouble with the M96/7 oversized engines is that increasing torque at low revs is more likely to make them score unless the bores are also changed to Nikasil (which ours are).
Usually a 3.6 to 3.9 or 3.4 to 3.7 M96/7 increases torque about 15% without changing anything else and raises peak BHP by nearer 8%.
Increasing the capacity too much can result in peak BHP being hardly any different but increases in torque from even lower revs being even more dramatic (typical or our 3.2 Boxster to 3.7 which is much quicker but does not have a lot more bhp at peak revs).
Jakes 4.0 I am sure will be awesome.
Baz
I do not understand?! What do I do to prevent a "bore score"? I do not drive over 3000/3500 rpm until my oil temperature is balanced.
Will any engine 3.8 997.1 end up with a "bore score" or just a certain series of motors? I live in an area with hot weather and use mobil 1 5w50. My engine from 2007. Is the "bore score" related to the mileage of the vehicle? (I am with about 120,000 miles).
Every time I read it, I'm anxious..
A final question, is after engine construction and coating Nikasil reliability of the engine is like a Metzger engine?
Many thanks in advance!
03-02-2019, 07:04 AM
#523
F911 – there is a variability in the distribution of the silicon in the Lokasil you have in your bores that make some engines far more likely to last for years and huge mileages while others do not because the rate of silicon particles that become detached from the bores to impinge on the piston coating under load may be faster or slower.
Then the amount of pressure that is pressing the piston coating against those particles that are released influences the damage that can be done by them to the piston coating.
This pressure of course relating to the amount of throttle regularly used especially in low to moderate rev ranges (less pressures due to the inertia of the piston travel at higher revs).
Finally the piston coating themselves vary. We have pictures of some where the coating had not bonded properly and had peeled off, others where the bonding is good but the rate of silicon release was high and just made the coating wear away and others where larger silicon particles picked spots away from the surface.
All this makes predicting the anticipated life span completely impossible, but as the engines wear the piston clearances increase and this gives more space for the particles to escape but only if the oil viscosity is increased slightly to fill the gap to let the particles float away (especially as more clearance heats up the piston face more as there is more blow by and this makes the oil film protecting the piston surface thinner).
Chwheeler – very good question that requires a longer answer than space and patience allow for here. Considering tuning N/A engines of the same capacity - the problem is that BHP is the multiple of torque * revs (ignoring constants) – so you can achieve higher BHP if you raise the revs more than you reduce the torque. To do this you would usually require hotter cams, bigger inlets and/or exhausts etc and this in turn usually reduces the power band. However if you raise the revs there are 5 counter-productive consequences.
(1) There is less time that the valves are open so less time to move air (hence the need for larger breathing adjustments) but these then also make the mid-range torque reduce (because the tuning is too orientated to high revs breathing).
(2) If you raise the revs say 10% you also increase the “rev drop” by 10% (the revs you drop to from changing gear at max revs to the revs you settle on in the next gear) and this means that you must somehow not only increase the revs but also the “power band” which is usually impossible.
(3) Your car is already geared higher than you would use on road or track flat out in top gear but raising the revs by say 10% also raises all the speeds reached in each gear even further.
(4) It is torque that accelerates the car (not BHP) and the torque at the rear wheels reduces by the same proportion that the gear ratio (and wheel speed) speeds up as you change up in the gears. This means that as you go faster you get less and less torque driving the rear wheels (eventually around a quarter of the torque in top than in 1st).
(5) The consequence of the above is that to exploit the benefits of tuning for higher revs and peak BHP you need to either lower the crown wheel and pinion ratio, fit closer ratio gears inside the gearbox – or both – which is usually outside the remit for this kind of tuning on Porsche’s. F1 engines revving to 18000 rpm would double the top speed they are set for compared to an engine revving at 9000 rpm but reduce the gearing to suit and in so doing increase torque once again.
Fortunately building an oversized engine does the opposite and increases the torque in the range that you drive in when changing gear upwards and also has the added benefit that you can accelerate more quickly from mid-range revs without the need to drop down a gear and rev the engine higher.
This benefit therefore of an oversized engine resultins in (usually) a bigger increase in mid-range torque % than the % capacity increase and is a massive benefit to a great driving experience and performance even though it does not usually increase the measure of peak BHP by the same proportion.
An oversized engine therefore will usually be great to drive and faster but not necessarily have such a high BHP figure to brag about.
Also different dyno’s can provide different BHP results because the larger the porting and valving the longer unsteady gas flow takes to settle down. This means that a dyno run that selects fixed rev breaks and is allowed to settle in each will give much higher results than a dynamic or inertia run. The most representative will be a run set/timed at a resistance similar to the rate the car would normally accelerate in the chosen gear when in use – but will not give the highest BHP result even though it represents the most relevant performance.
To make things worse “engine dynos” can reproduce even different results so you may have seen than while the owner’s manuals for Porsche’s have gradually left out various graphs and figures and made the BHP graph become a simplified set of almost straight lines – independent dyno runs will still reproduce curves. Finally all dyno runs use adjustment factors to alter the results which can be used to try and get closer to the accurate output or to alter the outcome more positively for the guy paying for it.
All the above would take a full sized book to properly explain but frankly it makes discussing BHP – for me – irrelevant and what I would need to see in order to compare performances would probably be timed acceleration runs through say 2nd to 4th gear flat out! And if you did that with an oversized engine you would get fantastic results compared to most other alternatives.
The only other way to overcome the reduction in the time available for the valves to breathe air as revs rise – is forced induction which introduces a whole new “book”. Anything that increases the pressure between the piston and the cylinder bore surface will shorten piston and bore life if the pistons are not hard iron plated and the bores are Lokasil or perhaps lees of a problem – Alusil. However Nikasil will take the high pressures without failure if everything else is set up right. So M96/7 engines creating more torque benefit from Nikasil bores and so probably will oversized Alusil engines.
We do not re-plate the Alusil or Lokasil bores with Nikasil. We machine out all of the original liner and fit a new wet alloy cylinder plated with Nikasil. The substrate of lokasil that has failed worries us enough to stick to replacing the cylinders which with the tops fixed rigidly with a precision machined location converting the engine to a closed deck construction is beneficial while a thicker wet liner remains more stable and has better heat transfer.
It may be possible to re-plate 9A1 engines with Nikasil but unlike the M96/7 engines the bores have a blind bottom so it would be very difficult to hone to the bottom of the bore to size and to create the right honing angles. That it not to say it cannot be done but we are sticking to our well proven solution for all models.
Baz
Then the amount of pressure that is pressing the piston coating against those particles that are released influences the damage that can be done by them to the piston coating.
This pressure of course relating to the amount of throttle regularly used especially in low to moderate rev ranges (less pressures due to the inertia of the piston travel at higher revs).
Finally the piston coating themselves vary. We have pictures of some where the coating had not bonded properly and had peeled off, others where the bonding is good but the rate of silicon release was high and just made the coating wear away and others where larger silicon particles picked spots away from the surface.
All this makes predicting the anticipated life span completely impossible, but as the engines wear the piston clearances increase and this gives more space for the particles to escape but only if the oil viscosity is increased slightly to fill the gap to let the particles float away (especially as more clearance heats up the piston face more as there is more blow by and this makes the oil film protecting the piston surface thinner).
Chwheeler – very good question that requires a longer answer than space and patience allow for here. Considering tuning N/A engines of the same capacity - the problem is that BHP is the multiple of torque * revs (ignoring constants) – so you can achieve higher BHP if you raise the revs more than you reduce the torque. To do this you would usually require hotter cams, bigger inlets and/or exhausts etc and this in turn usually reduces the power band. However if you raise the revs there are 5 counter-productive consequences.
(1) There is less time that the valves are open so less time to move air (hence the need for larger breathing adjustments) but these then also make the mid-range torque reduce (because the tuning is too orientated to high revs breathing).
(2) If you raise the revs say 10% you also increase the “rev drop” by 10% (the revs you drop to from changing gear at max revs to the revs you settle on in the next gear) and this means that you must somehow not only increase the revs but also the “power band” which is usually impossible.
(3) Your car is already geared higher than you would use on road or track flat out in top gear but raising the revs by say 10% also raises all the speeds reached in each gear even further.
(4) It is torque that accelerates the car (not BHP) and the torque at the rear wheels reduces by the same proportion that the gear ratio (and wheel speed) speeds up as you change up in the gears. This means that as you go faster you get less and less torque driving the rear wheels (eventually around a quarter of the torque in top than in 1st).
(5) The consequence of the above is that to exploit the benefits of tuning for higher revs and peak BHP you need to either lower the crown wheel and pinion ratio, fit closer ratio gears inside the gearbox – or both – which is usually outside the remit for this kind of tuning on Porsche’s. F1 engines revving to 18000 rpm would double the top speed they are set for compared to an engine revving at 9000 rpm but reduce the gearing to suit and in so doing increase torque once again.
Fortunately building an oversized engine does the opposite and increases the torque in the range that you drive in when changing gear upwards and also has the added benefit that you can accelerate more quickly from mid-range revs without the need to drop down a gear and rev the engine higher.
This benefit therefore of an oversized engine resultins in (usually) a bigger increase in mid-range torque % than the % capacity increase and is a massive benefit to a great driving experience and performance even though it does not usually increase the measure of peak BHP by the same proportion.
An oversized engine therefore will usually be great to drive and faster but not necessarily have such a high BHP figure to brag about.
Also different dyno’s can provide different BHP results because the larger the porting and valving the longer unsteady gas flow takes to settle down. This means that a dyno run that selects fixed rev breaks and is allowed to settle in each will give much higher results than a dynamic or inertia run. The most representative will be a run set/timed at a resistance similar to the rate the car would normally accelerate in the chosen gear when in use – but will not give the highest BHP result even though it represents the most relevant performance.
To make things worse “engine dynos” can reproduce even different results so you may have seen than while the owner’s manuals for Porsche’s have gradually left out various graphs and figures and made the BHP graph become a simplified set of almost straight lines – independent dyno runs will still reproduce curves. Finally all dyno runs use adjustment factors to alter the results which can be used to try and get closer to the accurate output or to alter the outcome more positively for the guy paying for it.
All the above would take a full sized book to properly explain but frankly it makes discussing BHP – for me – irrelevant and what I would need to see in order to compare performances would probably be timed acceleration runs through say 2nd to 4th gear flat out! And if you did that with an oversized engine you would get fantastic results compared to most other alternatives.
The only other way to overcome the reduction in the time available for the valves to breathe air as revs rise – is forced induction which introduces a whole new “book”. Anything that increases the pressure between the piston and the cylinder bore surface will shorten piston and bore life if the pistons are not hard iron plated and the bores are Lokasil or perhaps lees of a problem – Alusil. However Nikasil will take the high pressures without failure if everything else is set up right. So M96/7 engines creating more torque benefit from Nikasil bores and so probably will oversized Alusil engines.
We do not re-plate the Alusil or Lokasil bores with Nikasil. We machine out all of the original liner and fit a new wet alloy cylinder plated with Nikasil. The substrate of lokasil that has failed worries us enough to stick to replacing the cylinders which with the tops fixed rigidly with a precision machined location converting the engine to a closed deck construction is beneficial while a thicker wet liner remains more stable and has better heat transfer.
It may be possible to re-plate 9A1 engines with Nikasil but unlike the M96/7 engines the bores have a blind bottom so it would be very difficult to hone to the bottom of the bore to size and to create the right honing angles. That it not to say it cannot be done but we are sticking to our well proven solution for all models.
Baz
Last edited by bazhart; 03-02-2019 at 07:10 AM. Reason: spacing lost
03-02-2019, 10:19 AM
#524
Rennlist Member
Thanks
03-02-2019, 04:30 PM
#525
These questions are certainly valid in regards to the video I post. Due to the nature of the direct injection systems, it's all about engineering a way to reduce or possibly eliminating carbon deposits on the valves. I'm also very curious how the valves look on the OP's failed engine. What the experts are saying is due to the emission control and regulations, manufacturers had to change the combustion system on their engines to meet the ever so changing regulations. My question is I wonder if Porsche was going to keep the same MY97 engines on their 911 longer if regulations remain the same since then....?