My porsche 944 S2 16 valve turbo project
12-13-2013, 06:08 AM
#151
I removed what I first posted about turbo sizing, as I realised Tim's turbo is larger than I first thought.
I'd be interested to know the actual intake air temperature at the end of the run, as I think the choking point of the compressor may not be far.
But anyway, even if the curves might end up slightly different on a car dyno, that thing is sure going to be crazy fast
I'd be interested to know the actual intake air temperature at the end of the run, as I think the choking point of the compressor may not be far.
But anyway, even if the curves might end up slightly different on a car dyno, that thing is sure going to be crazy fast
12-13-2013, 06:09 AM
#152
Rennlist Member
...
12-13-2013, 06:11 AM
#153
Rennlist Member
"Yes, also aware of his being an 8V, thus my interest if the head being so much better allows this large increase in "safe" boost. As Dike mentioned like to see the numbers when installed into the car and on a chassis dyno. Good point on the turbo sizing."
I think you'll find that's spelled 'Dyke' Eric...lol
Also looking forward to the real world results but so far, so good. Congrats Tim.
I think you'll find that's spelled 'Dyke' Eric...lol
Also looking forward to the real world results but so far, so good. Congrats Tim.
12-13-2013, 06:16 AM
#156
Nordschleife Master
Tom M'Guinn runs an 8V, so the comparison isn't exactly fair.
The way I see it is that it may be preferable when using a large turbo to increase power by playing with ignition timing rather than with boost (*), while with a smaller, fast spooling turbo like seems to be the case here (61 inducer is way smaller than most folks use for a 3.0L engine), maximising power by increasing boost makes more sense than pushing the ignition profile.
With that kind of power on such a "small" compressor I'm curious how close to the choking point of the compressor Tim got.
(*) which means the rest of the engine will have gone the required mods (intake, exhaust) to make it breathe so that the large compressor flows as much as it can.
The way I see it is that it may be preferable when using a large turbo to increase power by playing with ignition timing rather than with boost (*), while with a smaller, fast spooling turbo like seems to be the case here (61 inducer is way smaller than most folks use for a 3.0L engine), maximising power by increasing boost makes more sense than pushing the ignition profile.
With that kind of power on such a "small" compressor I'm curious how close to the choking point of the compressor Tim got.
(*) which means the rest of the engine will have gone the required mods (intake, exhaust) to make it breathe so that the large compressor flows as much as it can.
The 16v doesn't need as much ignition advance either so comparing ignition tables isn't of much use either.
Given the turbo is still within its effeciency zone more boost will aways trump more ignition advance. All IMHO of course
In fact boost is favoured over ignition advance for reliability reasons by car manufacturers. The 944 community have a much higher than reasonable fear of boost levels. Take the 991 turbo for instance. It has a boost level of 1.2 bar from the factory with a 0.15 bar overboost. Factory! Sure it has direct injection which enables a bit higher boost but still. You can be certain that the factory would use higher advance with lower boost if they thought it to be a safer approach.
The 997 Mk1 Turbo have non direct injection and the stock boost is 1.0 bar with a 0.2 bar overboost.
These cars usually run about 1.4 bar of boost with a simple remap. So to conclude... there is no reason for 944 community to be so scared of boost on a built and tuned engine. Boost by itself won't blow headgaskets.
12-13-2013, 06:26 AM
#157
Drifting
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Yes, I was just reading an article on a new AMG turbo 4 Merc that is running 26 psi factory! Pretty sweet car actually, I forgot what the model was.
12-13-2013, 06:32 AM
#158
12-13-2013, 07:53 AM
#159
Nordschleife Master
Sure, but the point is that boost wins over ignition advance when it comes to making more power AND it's not as "dangerous" as the average 944 owner thinks.
12-13-2013, 01:48 PM
#161
Instructor
Thread Starter
The air temp on the dyno sheet is not air charge but cell air temp.
The dyno runs a correction system to correct any discrepencies in baro, air temp etc etc so i have no worries in the engine repeating itself any pull on any day.
Yes, I was aware of this, but still never seen 26 psi, especially on brand new build, no break in at all mentioned, block not sleeved, engine out of car on dyno, so I would also assume no knock monitoring, unless he has that fancy headphone and stethoscope setup.
Tom runs 100 octane 100% of the time, but never remember him mention more than 22psi ever, he has all kinds of knock monitoring enabled and still has some events at 20, with what I am sure is one of the better tuned engines around. I will be very curious as to the longevity of this build. I have been collecting parts for some time now. Going to attempt one of these as well. Tim appears to be pushing the limits, but I am all ears, very interesting. One of the best charts I have ever seen.
Tom runs 100 octane 100% of the time, but never remember him mention more than 22psi ever, he has all kinds of knock monitoring enabled and still has some events at 20, with what I am sure is one of the better tuned engines around. I will be very curious as to the longevity of this build. I have been collecting parts for some time now. Going to attempt one of these as well. Tim appears to be pushing the limits, but I am all ears, very interesting. One of the best charts I have ever seen.
The block has also been linered and knock systems are used at all times.
I run knock control in my pectel ecu and also have a electronic knock detection earphones on myself.
We were more than happy to run this boost, we map engines from 32-42 psi on a daily basis on the cosworth yb, so using our knowledge from those into a very similar design 944 16v we know we are still on the safe side.
The results are great and a very nice accomplishment but you cannot compare the curve or spool of a static engine dyno run with a dynamic dyno run.
If you lock rpms long enough at each 500 rpm steps at 100% throttle you can get a huge turbo to spool very low down in the rpm range.
This is not to take anything away from Tim's work, absolutely not. But apples needs to be compared with apples and oranges with oranges
If you lock rpms long enough at each 500 rpm steps at 100% throttle you can get a huge turbo to spool very low down in the rpm range.
This is not to take anything away from Tim's work, absolutely not. But apples needs to be compared with apples and oranges with oranges
i plan to run my car on the rolling road when its complete so will post my findings.
i also have a very agrestive anti lag system so i dont think ill be worried about when the boost comes in, but what happens when it is in.
i will be using the latest in garret bar and plate intercooler cores so charge temps will be under control.
heat shouldnt be an issue with ceramic coated system and the downpipe size is as used on the dyno then into a more than capable 2 x 2.5" system.
The ecu will look after my water injection system should my intercooler not cope if it was very hot! (note water injection not water spray..)
my only losses should be alternator and power steering which we in testing find to loose 2-4bhp.
12-13-2013, 01:59 PM
#162
Rainman
Rennlist Member
Rennlist Member
yes we measured egt and it was between 750 and 800 degree C on WOT
It is an air-water cooler on the dyno and air charge temps are controlled to 40 degrees C to replicate in car figures for optimum accuracy.
The air temp on the dyno sheet is not air charge but cell air temp.
As i said earlier in the thread, the differences in baro and air temp was because the screamer pipe exhaust system blew slightly so i had to repair it and pull the engine the next day.
The dyno runs a correction system to correct any discrepencies in baro, air temp etc etc so i have no worries in the engine repeating itself any pull on any day.
The engine has been on the dyno for a number of days and is well and truely run in.
The block has also been linered and knock systems are used at all times.
I run knock control in my pectel ecu and also have a electronic knock detection earphones on myself.
We were more than happy to run this boost, we map engines from 32-42 psi on a daily basis on the cosworth yb, so using our knowledge from those into a very similar design 944 16v we know we are still on the safe side.
This is correct, we generally loose 2-300 rpm of spool from a static load test to a run through test.
i plan to run my car on the rolling road when its complete so will post my findings.
i also have a very agrestive anti lag system so i dont think ill be worried about when the boost comes in, but what happens when it is in.
I expect to loose very minmal amounts.
i will be using the latest in garret bar and plate intercooler cores so charge temps will be under control.
heat shouldnt be an issue with ceramic coated system and the downpipe size is as used on the dyno then into a more than capable 2 x 2.5" system.
The ecu will look after my water injection system should my intercooler not cope if it was very hot! (note water injection not water spray..)
my only losses should be alternator and power steering which we in testing find to loose 2-4bhp.
It is an air-water cooler on the dyno and air charge temps are controlled to 40 degrees C to replicate in car figures for optimum accuracy.
The air temp on the dyno sheet is not air charge but cell air temp.
As i said earlier in the thread, the differences in baro and air temp was because the screamer pipe exhaust system blew slightly so i had to repair it and pull the engine the next day.
The dyno runs a correction system to correct any discrepencies in baro, air temp etc etc so i have no worries in the engine repeating itself any pull on any day.
The engine has been on the dyno for a number of days and is well and truely run in.
The block has also been linered and knock systems are used at all times.
I run knock control in my pectel ecu and also have a electronic knock detection earphones on myself.
We were more than happy to run this boost, we map engines from 32-42 psi on a daily basis on the cosworth yb, so using our knowledge from those into a very similar design 944 16v we know we are still on the safe side.
This is correct, we generally loose 2-300 rpm of spool from a static load test to a run through test.
i plan to run my car on the rolling road when its complete so will post my findings.
i also have a very agrestive anti lag system so i dont think ill be worried about when the boost comes in, but what happens when it is in.
I expect to loose very minmal amounts.
i will be using the latest in garret bar and plate intercooler cores so charge temps will be under control.
heat shouldnt be an issue with ceramic coated system and the downpipe size is as used on the dyno then into a more than capable 2 x 2.5" system.
The ecu will look after my water injection system should my intercooler not cope if it was very hot! (note water injection not water spray..)
my only losses should be alternator and power steering which we in testing find to loose 2-4bhp.
...so how much for a duplicate?
12-16-2013, 04:21 AM
#163
Three Wheelin'
12-22-2013, 01:58 PM
#165
Instructor
Thread Starter
Over the weekend, I have cleaned under the bonnet, touch up any paintwork and then sat the engine. I've got one or two alterations to make, but nothing to tricky.
