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Do you have any datalogs? Seeing RPM, boost pressure, and TPS down a 1/4-mile run would be helpful. A 3rd-gear rolling pull with tip-in at 5K RPM would help show the transient response.
The dyno looks great, but as many have mentioned it looks like there is an issue on the top end. Either a boost leak or some kind of restriction, or temperature raise (intercooler heat soak or similar)
I would sort that out as a priority. At least make sure it isn't a boost leak because that can damage a turbo running off the edge like that several times, overspeed condition is potential, plus the engine backpressure goes up significantly if the leak is large and that can facilitate detonation especially with poor fuels.
There are methods which help maintain impeller wheel speed during a shift which it sounds like you are having trouble with.
To do this properly a recirculation style bypass that returns boost pressure from the compressor outlet, recirculates back into the inlet. Make sure the bypass functions as close to the compressor as possible, and well before any heat exchangers. This raises inlet pressure and maintains some of the kinetic energy investment imparted to air molecules originally by the compressor from the first time around. Also make sure there is no water-hammer (pressure wave) during throttle valve closure by making sure the bypass is adequate for the compressor flow rate. Any delay (often due to small vacuum line or T-vacuum line or wrong style of bypass valve used, or poor positioning) will exacerbate impeller wheel speed changes.
Last edited by KingTal0n; Jul 3, 2019 at 07:50 AM.
The Red on full tilt should trap around/over 130+ on a full weight car at the drag strip with evo 8 gearing. Its not a "big turbo" by any means . It shouldn't feel laggy. I think its a great match for a street Evo. I wouldn't consider any smaller personally unless it was for Auto X.
What did you run in the 1/4?
Maybe the car was turned down after that run, or has some other issue.
It looks like its tapering more then usual after 6500. Its about 50-100whp down from most after that point. I would check the WG preload (at least 2 turns from being able to put it on the flapper arm) , Do you have a 22-25lb wastegate spring? I presume its on an EBC. The MHI red should make around 600whp + almost to 8000rpm. God bless Cam control. And larger cranks. Really wakes things up early.
If all the results were posted in SAE it would be a better comparison but they are in STD. It still shows the difference cam control, strokers and boost control out the top can make.
OP results 2.0 non mivec STD on smoothing 5
My car on stock Mivec Cam 2.0 engine smoothing 0 on STD and built 2.2 on smoothing 0 . Sidenote, The mivec with stock cams spools up about 300rpm + faster then the OP non mivec results
OP never really came back, Its either as u said a W/G issue or its poor cam matched to the turbo and its falling off up top. either that or its getting too hot on the intake temps and needs a bigger intercooler or sumin. its all guesswork till we see some proper logs
Jul 1, 2019, 05:35 PM
