I lightly moded my Evo 6 while attempting to maintain optimal low end, turbo response since I use the car for AutoX. The engine is 100% stock, never been opened before, I replaced my GSR Turbo with a 60s series Evo 6.5 turbo to enhance response. I installed GSC S1 cams & a mid-sized HKS intercooler rated at 450hp & a Forge wastegate actuator, 15psi spring, Grimmspeed MBC. I kept the stock downpipe & IC piping, again with low end performance in mind.
But I seem to have failed as turbo spool seems slow considering my setup!
I don't have a map sensor to log boost, but load-wise, in 3rd gear wot my numbers are: 125load at 3000rpm, 165 at 3500, 200 at 3800, 260 at 4900.
I tested the following:
Turbo, it's in an excellent shape
Leaks, negative
Engine compression, all cylinders at 11
My suspects are:
IC stock upper pipe, the mid rubber section seems to be expanding under boost.
S1 cams, despite being a mild duration cams at 268, but their lift numbers are relatively high at 11in & 10.5ex

I'd appreciate your feedback

 

Would check wastegate pre-load and your WGDC in the tune.

 

I did check the actuator pre-load & it seems fine, I had just installed a new Forge actuator, so it was installed fine with the right pre-load. The stock boost solenoid is disconnected since I'm using an MBC.

 

did you buy a used turbo or new?

I have seen the flappers or housings bend and WG flapper starts leaking leading to slow spool..

retaring timing in the spool up area can get you some spool..

 

Good points kikiturbo & forskin fred, I'll reinspect the wastegate & housing.

 

Some timing tuning and afr tuning should be in order.

Depending on what fuel you use, leaning out the spool afr will spool faster.

 

unless you lean it too much,...

 

That's why the tyoe of fuel matters sir.

I spool 12.8 on e-85

 

Hi Foxbat.
I also suspect 2 things.

Cams and Wastegate flapper.

 

yeah.. I like to keep it in 12 - 13 afr during spool... I remember switching a car to SD and suddenly it started spooling 1000 RPM late, then I look at the log and see 15 AFR during spool..

 

Nothing you have done should have had that effect. The car needs to be tuned, if you want more low end you may want to advance the intake maybe 2 degrees and retard exhaust 1 which will build mid range/low end. You need to address the hotside and down pipe to relieve back pressure there. Leave everything else in place..SPool should be all in full boost by 2500-3k if everything else is done correctly. No reason the cams should be the problem unless they are retarded- a lot. I assume they are straight up? Sounds more like boost leak or wastegate issues to me--but hey.

 

The car was tuned with almost perfect AFR numbers, the tune is not the issue. I didn't install adjustable cam gears, so the cams are set at 0. I'll have to check the hotside & wastegate, but I'm 90% positive I've inspected the flapper when installing the new wastegate actuator.

 

I highly doubt it is the cams... to me it sounds like a bent flapper or a problem with the exhaust turbine housing.. nothing you can check with the turbo on as it takes verry little for the flapper to leak..

could be the tune but hard to say without the log.. but I doubt it if the car is still on MAF