GT4 - Unlocking the Power Potential!
09-25-2020, 04:18 AM
#1111
I updated my 981 GT4 to a custom tune using Dundon intake runners, IPD plenum, and GT3 throttle body which resulted in ~377 HP to the wheels (baseline was about ~350 before mods).
This was with factory PSE and no other mods.
Makes it about 425HP using 12.5% driveline loss and a much smoother power curve from stock.
This was with factory PSE and no other mods.
Makes it about 425HP using 12.5% driveline loss and a much smoother power curve from stock.
09-26-2020, 04:00 PM
#1113
quite interesting ->
new hypothesis:
you can go the ipd plus intake runners + custom tune way OR
headers and custom tune way to eliminate midrange torque dip -> most driveability improvement.
it seems that when custom tune plus ipd plenum or custom tune with headers is there before adding the other one - there is limited gains?
power combo would be headers for 3.5k-6k more torque and sound
PLUS dundon intake runners with Plenum/TB for giving it more gt3 feeling from 7k to rev-limiter.
do you agree?
new hypothesis:
you can go the ipd plus intake runners + custom tune way OR
headers and custom tune way to eliminate midrange torque dip -> most driveability improvement.
it seems that when custom tune plus ipd plenum or custom tune with headers is there before adding the other one - there is limited gains?
power combo would be headers for 3.5k-6k more torque and sound
PLUS dundon intake runners with Plenum/TB for giving it more gt3 feeling from 7k to rev-limiter. do you agree?
09-26-2020, 08:22 PM
#1114
I updated my 981 GT4 to a custom tune using Dundon intake runners, IPD plenum, and GT3 throttle body which resulted in ~377 HP to the wheels (baseline was about ~350 before mods).
This was with factory PSE and no other mods.
Makes it about 425HP using 12.5% driveline loss and a much smoother power curve from stock.
This was with factory PSE and no other mods.
Makes it about 425HP using 12.5% driveline loss and a much smoother power curve from stock.
09-26-2020, 08:36 PM
#1115
Just used the math referenced in this post for driveline loss... 
The dyno shows the before and after actuals. Overall gain is okay but with much smoother curve and better top end. I was happy with that.
This configuration also being submitted by Dundon for CARB certification I heard which is good for us Cali folks.
The dyno shows the before and after actuals. Overall gain is okay but with much smoother curve and better top end. I was happy with that.
This configuration also being submitted by Dundon for CARB certification I heard which is good for us Cali folks.
09-26-2020, 10:08 PM
#1116
Agree it's a great power curve but your standard car would need to be making close to 400 bhp to end up where you have. I think the runners must remove the "double hump" that plagues these engines. I have done a lot of development, and dozens of dyno hours, on mine (see a previous thread I started) and I ended up with 440 bhp at the crank. I have standard runners and will probably fit a 718 Clubsport intake manifold as my last 3.8 mod. After that its 4.5L for me.
09-27-2020, 12:07 AM
#1117
Three Wheelin'
09-27-2020, 12:10 AM
#1118
Three Wheelin'
Agree it's a great power curve but your standard car would need to be making close to 400 bhp to end up where you have. I think the runners must remove the "double hump" that plagues these engines. I have done a lot of development, and dozens of dyno hours, on mine (see a previous thread I started) and I ended up with 440 bhp at the crank. I have standard runners and will probably fit a 718 Clubsport intake manifold as my last 3.8 mod. After that its 4.5L for me.
09-27-2020, 05:17 AM
#1119
Ajw - search Warwick’s post about his tuning journey reference above. Straight thru headers hi flow heads and a lot of bespoke and expensive tuning.
09-27-2020, 07:58 AM
#1120
Just a refresh of a previous recent post here. My car was busting noise limits at local tracks and I asked my shop to modify the standard muffler box like they did for my 996 GT3 many years ago. They cut he top open and found the internal pipe (in the loud tract) was a smaller diameter than the exhaust system over axel pipes. So cut that out, put in full size perforated stainless pipe, wrapped it in stainless wool and packed the boxes with that wool and welded it up. The car now just has wide open exhaust all the time but easily passes all track limits, is much easier and civilised to drive on the freeway, does not drone at all and makes a few more horsepower than when it was "noisy". A really good mod if anyone is having noise problems.
09-27-2020, 01:46 PM
#1122
Three Wheelin'
09-27-2020, 01:51 PM
#1123
Three Wheelin'
Just a refresh of a previous recent post here. My car was busting noise limits at local tracks and I asked my shop to modify the standard muffler box like they did for my 996 GT3 many years ago. They cut he top open and found the internal pipe (in the loud tract) was a smaller diameter than the exhaust system over axel pipes. So cut that out, put in full size perforated stainless pipe, wrapped it in stainless wool and packed the boxes with that wool and welded it up. The car now just has wide open exhaust all the time but easily passes all track limits, is much easier and civilised to drive on the freeway, does not drone at all and makes a few more horsepower than when it was "noisy". A really good mod if anyone is having noise problems.
09-27-2020, 03:36 PM
#1124
Thanks again for posting this! I'veI've been thinking about doing this ever since your first post. I sold my Dundon quiet exhaust I used for track sound limits and will look at modding the stock pse over the winter for next year's track events! Think the pse with turndowns should be perfect....