Big T28 boost levels

[djsven]

Hi,

My car is a 95 eclipse GSX with the following modifications:
- FP big T28 with 17PSI actuator
- Greddy 24R FMIC + UICP + BOV
- Ported EVO III exhaust manifold + O2 housing
- Apex'I GT downpipe + catback + SAFC
- FIC 550cc injectors
- walbro 255 lph HP fuel pump
- AEM fuel rail + AFPR
- MSD 8.5mm spark plug wires
- MBC
- 6AN fuel lines
- ACT 2100 kit
- fidanza flywheel
- B&M short shifter
- OBD2 pocket logger

Still coming before the end of the month:
- AEM C2DI
- 1G head + intake manifold + throttle body

Questions:
What boost level would you recommend for street with 92 octane?
What boost level with 104+ octane booster?
What boost level with unleaded race gas?

How can you identify that your FP T28 is realy a T28?
The previous owner told me that there is a mark on the exhaust output side, but something like that you can fake!

What do I still need to do to get myself in the mid to low 12's?

Thanks for the help/info!

Sincerely,

Sven

 

[meh]

first off, your setup is really nice, and you should go with a bigger turbo if you have the money. second, if you have that much on the car you should know what that turbo is capable of, it is possible to get into the 12's with a T-28. since the t25/28 are cosmetically identical, it is nearly impossible to tell the difference just by looking at the two side by side. on the note of boost ranges, pump gas this turbo does best 14-18 psi, with race gas, i wouldnt go beyond 22psi simply because you are putting it past its efficiency range...good luck with the quest for 12's

 

[pboglio]

Sven,

My setup is very similar to yours. I have a FPT28/28 turbo, 1gen t-body, HKS 264/264 cams, 660 inj., turbo porting, 24"x10"x3" FMIC, etc. I'm running 19 psi of boost on 93 octane. This setup is good for 0-60 mph in 4.4 s and 0-100 mph in 10.38 s with quick shifting. On 100 octane unleaded I run 24 psi which drops down to 21 psi near redline with 0 knock counts.

I e-mailed Forced Performance and they said anything over 21 psi was just blowing hot air on the t28, but I've found there is still a lot more power with even higher boost levels. As long as you have the fuel support mods then you can run high boost with racing fuel with your front mount intercooler. Turbine backpressure will be huge but as long as your not knocking you should be ok. Just make sure your O2 volts are .88-.90 volts or higher and your knock counts are low.

What you would need to get mid to low 12s is cams, no doubt about it. My mass airflow numbers with cams @19 psi pump gas are the same as before cams with 24 psi on racegas. Your setup right now is already a high 12 second car with a good driver.

Forget the 104 octane boost, I wouldn't trust my engine on 24 psi with that crap. Use at least 100 octane unleaded ($3.75 gallon) and mix whatever ratio you need to keep your knock counts down, 100% would be preferable.

Your T28 should have 6 small and 6 large (12 total) impeller blades on the compressor
wheel with an inlet diameter of ~1.860" or slightly bigger for the BigT28. This is something you can easily measure by pulling off the MAF/turbo inlet pipe. The Big T28 compressor wheel is rated @ 37.5 lbs/min and the small T28 @ 35 lbs/min, according to Forced Performance's own literature. My guess is that the small T28 compressor wheel is the GT28R and the BigT28 is the GT28RS, compressor maps found at www.atpturbo.com. The Big T28 exhaust wheel has 9 blades and the small T28 has 10 blades, minor diameter measuring ~1.85". Good luck.

Gene

 

[IMMORTALSPYDER]

It's hard to tell the FP T28 from a stocker. My Big T28 Killer has a custom compressor housing so it looks stock to those who don't know what they're looking at, but a DSMer should be able to tell the difference.

 

[djsven]

Hi,

Thanks for all your replies. The reason why I ask about the difference between the big T28 and stock is that my performance hasn't realy changed. My quarter mile time went from 14.55 to 14.29, with the turbo upgrade and the supporting modifications, including the 3" exhaust, EVO III manifold, O2 housing and so on. This time difference should have been bigger! I just want to know that I wasn't screwed with the turbo, because it is hard to tell the difference! I am only going to race it 2 more times before the swap during the winter break. Also the reason why I asked about the 104+ is that it is hard to find unleaded race gas around here.

Thanks again!

Sincerely,

Sven

 

[Generation X]

I have been running 20psi daily for over 2 years now with 93 octane pump gas with supporting mods, including a set of HKS 264/272 cams with my FP ported Big28 with no problems what so ever. On a side note Dennis Grant made 348HP, and 376 lb ft of torque at the wheels with the FP Big28. He was running 24psi on race gas and using a stand alone.

 

[djsven]

Hi,

Nice reply!!! Brings a lot of confidence.
Thanks guys.

Sven

 

[Generation X]

Here is a link to Dennis Grants home page. farnorthracing.com