991 GT3/RS Headers and Lightweight Mufflers by Charles Dundon/RK Autowerks: Group Buy
10-27-2015, 05:41 PM
#46
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Just for reference. This dyno was done on a 248C like every other dyno I do. The PIWIS 2 tester was used to allow rolling road mode so it could be dyno ran on a 2wd dyno.
398-402whp, let's say 400whp peak. With a 15% loss that is 470 crank HP which these are SAE 468hp (475DIN) so this is right on target.
398-402whp, let's say 400whp peak. With a 15% loss that is 470 crank HP which these are SAE 468hp (475DIN) so this is right on target.
10-27-2015, 06:14 PM
#47
Three Wheelin'
Just for reference. This dyno was done on a 248C like every other dyno I do. The PIWIS 2 tester was used to allow rolling road mode so it could be dyno ran on a 2wd dyno.
398-402whp, let's say 400whp peak. With a 15% loss that is 470 crank HP which these are SAE 468hp (475DIN) so this is right on target.
398-402whp, let's say 400whp peak. With a 15% loss that is 470 crank HP which these are SAE 468hp (475DIN) so this is right on target.
10-27-2015, 06:27 PM
#49
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Honestly I do not think I had the exhaust button pressed.
The higher intake peak hp at the higher rpm is probably due to the cooler air temp as it was about 50deg out
The higher intake peak hp at the higher rpm is probably due to the cooler air temp as it was about 50deg out
10-27-2015, 07:10 PM
#50
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Runs 2-3 I turned off to compare.
There was one pull before run 1 but I forgot to hit record. I rolled into and went full throttle around 3000 and wot around 3500-3600 and somewhere around there I started recording.
On this car exhaust "off" the flaps open at WOT at 3400rpm as you can see the slight power rise from 3400-3600.
My exhaust setup with flaps open or closed makes the same power down low. No loss with them closed
10-30-2015, 12:22 AM
#51
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So just a quick update, we did go to the dyno, the current setup does make a solid 20whp and 25wtq. There is a few small issues I want to deal with to refine the exhaust to make it perfect. Dealing with the exhaust cam timing along with the decision by Porsche to delete the MAF, we have some adaption issues I believe we have to work though. I am modifying a few things and am going to go back to the dyno to test my theory and then will post up all of the data.
It is possible that my headers/exhaust is too efficient and it is beyond the adaption ability of the ECU
It is possible that my headers/exhaust is too efficient and it is beyond the adaption ability of the ECU
10-30-2015, 12:40 AM
#52
So just a quick update, we did go to the dyno, the current setup does make a solid 20whp and 25wtq. There is a few small issues I want to deal with to refine the exhaust to make it perfect. Dealing with the exhaust cam timing along with the decision by Porsche to delete the MAF, we have some adaption issues I believe we have to work though. I am modifying a few things and am going to go back to the dyno to test my theory and then will post up all of the data.
It is possible that my headers/exhaust is too efficient and it is beyond the adaption ability of the ECU
It is possible that my headers/exhaust is too efficient and it is beyond the adaption ability of the ECU
https://vimeo.com/144081655
Last edited by Jamie_GT3; 10-30-2015 at 12:57 AM.
10-30-2015, 08:15 AM
#53
Thanks for doing this Jaime! I'm super excited to see the results.
11-02-2015, 09:24 PM
#54
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*******I CANT GET THE VIDEOS TO WORK, NOT SURE WHY, LET ME KNOW WHAT I'M DOING WRONG AND I WILL FIX THEM SO THEY ARE EMBEDDED******
So I have been datalogging The 991 GT3 and testing several setups on the Dyno and am currently at this setup. I have one more revision to make that should make 6-10whp more from 6000+ over the current setup. The midrange loss could be tuned out if we had the ability to, but it is related to exhaust cam timing causing too much overlap for the longer runners. I will let jamie write this up in full detail.
I will say that these cars are a pain to fully adapt and take a lot of time, we have learned a lot in the last few weeks on these cars. These cars take many runs to adapt, so we decided to do a 2-3-4-5 gear run on the dyno to compare.
The power gains in our headers are available in the critical area of 6500-9000 rpm.**This is where the car will shift down to at the track at full throttle...**You can see this in the multi gear dyno graph. That loss in the middle is only there at WOT the car has more power at 50-70% than it does at WOT due to excessive cam overlap for emissions. With tuning, this whole dip can be tuned out, and in normal driving you dont feel it, and driving through it in 2-3rd gears you dont really notice it, if you are at 5000rpm in 3rd anyways, you can downshift to 2nd and so on.
as you can see in places we are making 30+whp over stock. my last revision I hope to have a 35whp gain at peak.
So I have been datalogging The 991 GT3 and testing several setups on the Dyno and am currently at this setup. I have one more revision to make that should make 6-10whp more from 6000+ over the current setup. The midrange loss could be tuned out if we had the ability to, but it is related to exhaust cam timing causing too much overlap for the longer runners. I will let jamie write this up in full detail.
I will say that these cars are a pain to fully adapt and take a lot of time, we have learned a lot in the last few weeks on these cars. These cars take many runs to adapt, so we decided to do a 2-3-4-5 gear run on the dyno to compare.
The power gains in our headers are available in the critical area of 6500-9000 rpm.**This is where the car will shift down to at the track at full throttle...**You can see this in the multi gear dyno graph. That loss in the middle is only there at WOT the car has more power at 50-70% than it does at WOT due to excessive cam overlap for emissions. With tuning, this whole dip can be tuned out, and in normal driving you dont feel it, and driving through it in 2-3rd gears you dont really notice it, if you are at 5000rpm in 3rd anyways, you can downshift to 2nd and so on.
as you can see in places we are making 30+whp over stock. my last revision I hope to have a 35whp gain at peak.
Last edited by Charles@dundonmotorsports; 11-04-2015 at 01:15 AM.
11-03-2015, 11:05 AM
#57
Three Wheelin'
11-03-2015, 11:26 PM
#59
I'm actively working on the tuning, a few weeks and it's fixed. The thing is the dip, you don't know it's there if we didn't tell you... When you get on the gas, car downshifts up the rev range and off you go!
Our latest and last rev has minimized the 5000rpm dip. Just keep an open mind and know that a car with bypass pipes, vs our setup. Let's just say all they'll see is tail lights...
Our latest and last rev has minimized the 5000rpm dip. Just keep an open mind and know that a car with bypass pipes, vs our setup. Let's just say all they'll see is tail lights...
11-04-2015, 10:28 AM
#60
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I'm actively working on the tuning, a few weeks and it's fixed. The thing is the dip, you don't know it's there if we didn't tell you... When you get on the gas, car downshifts up the rev range and off you go!
Our latest and last rev has minimized the 5000rpm dip. Just keep an open mind and know that a car with bypass pipes, vs our setup. Let's just say all they'll see is tail lights...
Our latest and last rev has minimized the 5000rpm dip. Just keep an open mind and know that a car with bypass pipes, vs our setup. Let's just say all they'll see is tail lights...