T28 and Hahn Big IC

[re-rx7]

Maybe someone can shine some light on this for me. I have a T28 Turbo that sor some reason likes to creep to 19 psi on a cool night and a Hahn Smic. Is it possible that this intercooler is not large enough for this turbo? Upon my initial research I concluded it was and found one to purchase. I only do Hwy pulls usually 4th gear and some of 5th. Im curious as to whether the timing or tune may be skewed since the dyno i only tune in third gear. Since judging by English racings writeup on tuning that SMIC are hard to tune for in the upper gears.

Any insight would be helpful. Thanks again.

S/n. max timing is 13 degrees with a 11.1-11.3 afr. Im thinkin it may be a lil lean? Tuning with ECU flash

 

[PieEyedPiper]

T25/T28's are less notorious for boost creep, but I think you're barking up the wrong tree. If you are experiencing boost creep, look at the hotside/exhaust instead. Search around for creep on 16g's and you'll find a bunch of ways to reduce or even eliminate creep.

People also experience 1-2 more psi sometimes on very cool evenings and such, is this more what you mean?

 

[re-rx7]

Yes, we tuned it on a war afternoon (80's). Last night it was probally in the 60's. I really dont understand why the T28 is creeping honestly.

 

[jtmcinder]

Is this a T28 with a T25-sized wastegate or the larger wastegate? If the former, port it, and try again.

 

[re-rx7]

Not the Fp28 so im assuming the latter. What would be the cause of the abnormal knock??

 

[jtmcinder]

The knock is more likely asking too much from a T28. I was focused on the creep. A T28 with a small wastegate can easily creep, especially with certain downpipes. A T25 can creep with the wrong (or right) downpipe.

 

[re-rx7]

Really? It creeps to 19 psi and stays put. I thought they were gd up to 23 or so?

 

[romeen]

Maybe someone can shine some light on this for me. I have a T28 Turbo that sor some reason likes to creep to 19 psi on a cool night and a Hahn Smic. Is it possible that this intercooler is not large enough for this turbo?

Are you using any type of air duct from the bumper cover to the SMIC? If not, then the intercooler definitely might not be sufficient for your setup. The size of the Hahn IC might be fine for that turbo but without the air duct (similar to stock) not enough air is going through the core of the IC to make it useful.

I'm using the Hahn SMIC with my EVO3 16G. Without ducting it heat soaks after only one hard pull. I've improvised some ducting by surgically altering the stock duct (it's ugly and temporary) for the purposes of testing. Haven't tested yet though because my car is awaiting an alignment and new tires before I drive it.

 

[re-rx7]

I have actually done what you did with stock duct. I trimmed so that it will fit it. I have some sheet metal that im gna wrk with as soon as i get some time off work. It is ugly as well. I trimmed the backside of the fender liner to fot the intercooler. Also i drove it today after the weather has warmed up and the issue has dissapeared. This leads me to believe that when it creeps on cool nights i may need to add more fuel at 19 psi ### right now i see right at 17-18 psi.

 

[romeen]

Do you have any comparisons before and after installing the duct? Or have you had the duct since first installing the IC?

 

[re-rx7]

Kinda. When i first got it i ran it w/o due to time constraints. The intercooler heated up quickly. Like hot to the touch. After trimming the stock duct it was amazing how much cooler it became. So there wud be some benefit to a custom scoop. How much improvement an is it worth the effort is the question.

 

[PieEyedPiper]

I just put this together - you're the guy from the ECU thread. http://www.dsmtuners.com/forums/tun...st-flashed-dsm-ecu-98-99-flashing-faq-31.html


Definitely put up a log.