Fast spooling turbo with xtra power is it possible?
08-19-2010, 09:44 AM
#16
08-19-2010, 10:03 AM
#17
I liked very much my chipped 2.5 with K26/8 turbo and never considered I could increase power without losing any of the good compromise it offers between response and power (torque curve is relatively wide), this is why I directly built a 3.0 with a "correctly-sized" dual ball bearing turbo that makes it feel like my chipped 2.5, say mid range performance, but with scaled-up power & torque curves. Off boost it's also much faster, and you would probably need to increase the CR on a 2.5 to hope get close, at the price of being limited to a relatively low peak boost - it's always the same old story, there is no replacement for cubic inches.
I don't want to sound pessimistic $-wise but it sounds like you will get satisfied only if you increase engine size!
I don't want to sound pessimistic $-wise but it sounds like you will get satisfied only if you increase engine size!
08-19-2010, 10:06 AM
#18
Chris,
I hear what you are saying about the "feel" vs "faster" but the black car pulled away with ease and it is stock. As for the dyno numbers I think the only real thing we can conclude is the boost level of the 89 which was at peak 15.6 roughly( as the hp/trq numbers seem like they may have been inflated). As for the stopwatch "test" to me and I own several cars it is about the feel and most evaluate any car new old sports luxury by the driving impression, so I think what you are saying is if the car is faster but does not feel it, it will be marginally faster not much more torque.
As for the stock turbo dropping off, when I drive highway say 70-80mph drop it down to 4th the stock set up has a lot of kick still at high speeds the car accelerates well. I know this is all common knowledge.
As for the improvements that should make power or improve the response and acceleration besides the turbo. The head, the cam, no cat, larger exhaust, slightly more displacement, software, lighter internals.
I thought these things combined with a more modern better turbo, would help the car in all areas of the rpm range. But even if I was misinformed and only the "top" end can be improved on a 2.5 which I think is what you are saying. Must it be at the sacrifice of the "low" end?
As it stands now I have not had a real good evaluation of the car for the obvious reasons. But have the option to change out turbo's to John's cheater "smaller" turbo or back to stock.
Thanks,
Bob
I hear what you are saying about the "feel" vs "faster" but the black car pulled away with ease and it is stock. As for the dyno numbers I think the only real thing we can conclude is the boost level of the 89 which was at peak 15.6 roughly( as the hp/trq numbers seem like they may have been inflated). As for the stopwatch "test" to me and I own several cars it is about the feel and most evaluate any car new old sports luxury by the driving impression, so I think what you are saying is if the car is faster but does not feel it, it will be marginally faster not much more torque.
As for the stock turbo dropping off, when I drive highway say 70-80mph drop it down to 4th the stock set up has a lot of kick still at high speeds the car accelerates well. I know this is all common knowledge.
As for the improvements that should make power or improve the response and acceleration besides the turbo. The head, the cam, no cat, larger exhaust, slightly more displacement, software, lighter internals.
I thought these things combined with a more modern better turbo, would help the car in all areas of the rpm range. But even if I was misinformed and only the "top" end can be improved on a 2.5 which I think is what you are saying. Must it be at the sacrifice of the "low" end?
As it stands now I have not had a real good evaluation of the car for the obvious reasons. But have the option to change out turbo's to John's cheater "smaller" turbo or back to stock.
Thanks,
Bob
A couple of thoughts –
Once you get to really tuning the car with the stage 2 turbo you will need a stop watch to confirm what it really going on. The stage 2 turbo on my old street car did not ‘feel’ as powerful as the previous turbo – but that was because it was much smoother in building boost. Once I measured the acceleration times and more importantly (to me anyway!) the increased RPM at the end of the straights at the track the additional power was much more evident.
Your 89 engine maybe stock internally but it was putting out some pretty decent power and running fairly high boost when we dynode it early this year. At lower PRM and at equal boost levels do not expect a huge difference in power. The K26/8 is at a nice point in its efficiency range at lower RPM and 15-20 lbs of boost. The big difference is when the RPMs come up - then the K26/8 will fall off quite a bit.
Keep in mind that the internals of the engine (for the most part) do not make more power – they need to be able to support the additional power being made by the changes to the induction (turbo, cam and head work) and engine management systems (tuning).
I know you might hate to hear this since you have spent quite a bit on the project – but a 2.5 engine running at the same boost will have a similar torque output (+/- 10%) as long as the system is within its efficiency range. The old K26/8 is right in its sweet spot at lower rpms – it will be hard to make a huge improvement. Above 4500 rpm the stage 2 will show a huge improvement – but that will not be evident in the initial ‘feel’ of power.
Once you get to really tuning the car with the stage 2 turbo you will need a stop watch to confirm what it really going on. The stage 2 turbo on my old street car did not ‘feel’ as powerful as the previous turbo – but that was because it was much smoother in building boost. Once I measured the acceleration times and more importantly (to me anyway!) the increased RPM at the end of the straights at the track the additional power was much more evident.
Your 89 engine maybe stock internally but it was putting out some pretty decent power and running fairly high boost when we dynode it early this year. At lower PRM and at equal boost levels do not expect a huge difference in power. The K26/8 is at a nice point in its efficiency range at lower RPM and 15-20 lbs of boost. The big difference is when the RPMs come up - then the K26/8 will fall off quite a bit.
Keep in mind that the internals of the engine (for the most part) do not make more power – they need to be able to support the additional power being made by the changes to the induction (turbo, cam and head work) and engine management systems (tuning).
I know you might hate to hear this since you have spent quite a bit on the project – but a 2.5 engine running at the same boost will have a similar torque output (+/- 10%) as long as the system is within its efficiency range. The old K26/8 is right in its sweet spot at lower rpms – it will be hard to make a huge improvement. Above 4500 rpm the stage 2 will show a huge improvement – but that will not be evident in the initial ‘feel’ of power.
08-19-2010, 10:12 AM
#19
Yes or go back to stock, I really wish this would have been explained from the very beginning by the shop.
I liked very much my chipped 2.5 with K26/8 turbo and never considered I could increase power without losing any of the good compromise it offers between response and power (torque curve is relatively wide), this is why I directly built a 3.0 with a "correctly-sized" dual ball bearing turbo that makes it feel like my chipped 2.5, say mid range performance, but with scaled-up power & torque curves. Off boost it's also much faster, and you would probably need to increase the CR on a 2.5 to hope get close, at the price of being limited to a relatively low peak boost - it's always the same old story, there is no replacement for cubic inches.
I don't want to sound pessimistic $-wise but it sounds like you will get satisfied only if you increase engine size!
I don't want to sound pessimistic $-wise but it sounds like you will get satisfied only if you increase engine size!
08-19-2010, 10:50 AM
#20
As others said, make sure you have everything set up correctly before deciding going back to the stock turbo.
FWIW a friend of mine runs a S3 on his '86 and though he usually is very critical with any of his car-related purchases I haven't heard a single complaint from him on his S3 kit.
FWIW a friend of mine runs a S3 on his '86 and though he usually is very critical with any of his car-related purchases I haven't heard a single complaint from him on his S3 kit.
08-19-2010, 10:55 AM
#21
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* Run #1:
Both cars in 2nd gear. Slow them down to 2000rpm. Bob driving black MY89 car says "GO" and get on it. Black car jumps ahead. Test #1 done by 3000RPM.
* Run #2:
Both cars in 2nd gear at 2500RPM. They both go WOT. White car S2R walks away.
* Run #3:
Back to the first test. starting at 2000rpm. Same results as test #1.
Things to consider:
- White car S2R was made to run rich on purpose as the boost was getting set. At 2000RPM, when you go to WOT and the AFR is rich the car will bog for a split second. Simple solution, pull back the fuel that was added once the boost control is set.
- White car S2R does not have the boost control configured yet. Boost fluctuates from 14psi down a few psi, back up... Solution, set the boost properly.
- S2R is sucking air through factory air box. Solution, open the air box to 3".
- At 2000RPM whoever says "GO" will get a jump, I don't care which car it is..
- Black car is running APE chips, ~16psi boost.
In my opinion, if anyone wants a powerband in the 2000-3000RPM range in 2nd gear. The followings are some of the options:
- Either a VERY small turbo (smaller than the K26/8) with aggressive timing and a stock cam. But forget about the 350-400hp.
- A positive displacement supercharger
- A high compression engine
- A big displacement engine (a V8?).
08-19-2010, 12:24 PM
#23
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I think that air box is realy letting the team down don't know of any other car with all those mods and a standard afm /airbox...its genrally the first thing to go ... far far B4 head work etc
08-19-2010, 01:33 PM
#24
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Help me get this straight. The car isn't close to being dialed in, and you're already frustrated by its performance in a "you say go" drag. Hell, I can drag the brake, get my boost to 15lbs, then say go and kill almost anything from 2K to 3K rpm, especially in 2d gear.
Tuning. Wastegate.
Tuning. Wastegate.
08-19-2010, 04:09 PM
#25
Three Wheelin'
Help me get this straight. The car isn't close to being dialed in, and you're already frustrated by its performance in a "you say go" drag. Hell, I can drag the brake, get my boost to 15lbs, then say go and kill almost anything from 2K to 3K rpm, especially in 2d gear.
Tuning. Wastegate.
Tuning. Wastegate.
08-19-2010, 05:05 PM
#26
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This is all being done with stock airbox and wg?????
The airbox alone is WAYYYYY restrictive to spool up. Almost as much as the cat.
Then add in a bad wg.
Problem solved. lol
The airbox alone is WAYYYYY restrictive to spool up. Almost as much as the cat.
Then add in a bad wg.
Problem solved. lol
08-19-2010, 06:00 PM
#27
Rennlist Member
All your answers are above. The project isn't finished yet, that's all.
08-19-2010, 06:26 PM
#28
Really where I am at is 3 months after purchase, an untuned car etc. and a lot of money spent.
John I sincerly hope you don't think I am talking down your products here as I am not. I have explained that I have not had the opportunity to evaluate them yet!
On the other hand I by no means am I looking for the best perfomance from 2-3k. That would be a narrow shortsigted request at best. Fact bieng I dont want to give up perfromance there. If it can not be improved than so be it.
This car is a street car and will be driven as such, so the low end to early mid range is important. Reading between the lines a few people have said this can not be improved on these cars. Maybe that is true I don't know.
If the top end is the only area that can be improved that is fine, but not at the sacrifice of the other range I am reffering to. I am hoping this can be proven wrong, I am also hoping that my shop can get the car tuned and all will be good. Not looking for a challange just want t get it right.
But in speaking with you and the shop Chris White's comments I am kind of getting the feel that this may be the case. I would be happier if I am proven differnt.
As for the airbox the shop did run it with a cone filter and did not see a dramatic difference.
As for 0-60 times Porsche always tries to improve on these numbers never seldom do I see a car running higher top speeds with lower 0-60.
As for the runs they were not scientific by any means, but agin the 89 car has no adj boost control, 21 year old motor, simple chip, stock exhaust and cat 40 track days on it and some mileage.
The fact that it pulls away with ease, I hope it is all tuning.
John I sincerly hope you don't think I am talking down your products here as I am not. I have explained that I have not had the opportunity to evaluate them yet!
On the other hand I by no means am I looking for the best perfomance from 2-3k. That would be a narrow shortsigted request at best. Fact bieng I dont want to give up perfromance there. If it can not be improved than so be it.
This car is a street car and will be driven as such, so the low end to early mid range is important. Reading between the lines a few people have said this can not be improved on these cars. Maybe that is true I don't know.
If the top end is the only area that can be improved that is fine, but not at the sacrifice of the other range I am reffering to. I am hoping this can be proven wrong, I am also hoping that my shop can get the car tuned and all will be good. Not looking for a challange just want t get it right.
But in speaking with you and the shop Chris White's comments I am kind of getting the feel that this may be the case. I would be happier if I am proven differnt.
As for the airbox the shop did run it with a cone filter and did not see a dramatic difference.
As for 0-60 times Porsche always tries to improve on these numbers never seldom do I see a car running higher top speeds with lower 0-60.
As for the runs they were not scientific by any means, but agin the 89 car has no adj boost control, 21 year old motor, simple chip, stock exhaust and cat 40 track days on it and some mileage.
The fact that it pulls away with ease, I hope it is all tuning.
Let's describe the test as I was told by the guy that was driving the cab with the S2R, while you were doing the run. It will give the viewers a better idea of what is taking place.
* Run #1:
Both cars in 2nd gear. Slow them down to 2000rpm. Bob driving black MY89 car says "GO" and get on it. Black car jumps ahead. Test #1 done by 3000RPM.
* Run #2:
Both cars in 2nd gear at 2500RPM. They both go WOT. White car S2R walks away.
* Run #3:
Back to the first test. starting at 2000rpm. Same results as test #1.
Things to consider:
- White car S2R was made to run rich on purpose as the boost was getting set. At 2000RPM, when you go to WOT and the AFR is rich the car will bog for a split second. Simple solution, pull back the fuel that was added once the boost control is set.
- White car S2R does not have the boost control configured yet. Boost fluctuates from 14psi down a few psi, back up... Solution, set the boost properly.
- S2R is sucking air through factory air box. Solution, open the air box to 3".
- At 2000RPM whoever says "GO" will get a jump, I don't care which car it is..
- Black car is running APE chips, ~16psi boost.
In my opinion, if anyone wants a powerband in the 2000-3000RPM range in 2nd gear. The followings are some of the options:
- Either a VERY small turbo (smaller than the K26/8) with aggressive timing and a stock cam. But forget about the 350-400hp.
- A positive displacement supercharger
- A high compression engine
- A big displacement engine (a V8?).
* Run #1:
Both cars in 2nd gear. Slow them down to 2000rpm. Bob driving black MY89 car says "GO" and get on it. Black car jumps ahead. Test #1 done by 3000RPM.
* Run #2:
Both cars in 2nd gear at 2500RPM. They both go WOT. White car S2R walks away.
* Run #3:
Back to the first test. starting at 2000rpm. Same results as test #1.
Things to consider:
- White car S2R was made to run rich on purpose as the boost was getting set. At 2000RPM, when you go to WOT and the AFR is rich the car will bog for a split second. Simple solution, pull back the fuel that was added once the boost control is set.
- White car S2R does not have the boost control configured yet. Boost fluctuates from 14psi down a few psi, back up... Solution, set the boost properly.
- S2R is sucking air through factory air box. Solution, open the air box to 3".
- At 2000RPM whoever says "GO" will get a jump, I don't care which car it is..
- Black car is running APE chips, ~16psi boost.
In my opinion, if anyone wants a powerband in the 2000-3000RPM range in 2nd gear. The followings are some of the options:
- Either a VERY small turbo (smaller than the K26/8) with aggressive timing and a stock cam. But forget about the 350-400hp.
- A positive displacement supercharger
- A high compression engine
- A big displacement engine (a V8?).
08-19-2010, 06:29 PM
#30