Going from a 14B to a 16G, my car is SLOW

NEO95GST · Sep 27, 2002

Okay first i did an intake leak test and found several leaks. One at BOV flapper, one at the RRE J Pipe, and at the throttle body. I fixed all of them and the throttle body one was a PITA... Well i also rewired my denso pump, and put it some RC550's. I set the AFC settings by the RRE settings to start. Well i drove the car around datalogging with the Alex Pepper Logger and the car felt fast, but the most i could tune was 14psi because my EGT would shoot up high. What i dont understand the car felt immediately faster after i did all the things mentioned and pulled hard, but as the days went by it got Slower...

Yesterday i put my 14B back in took the rewire of the fuel pump off and its Faster..I don't understand why

My mods are below.

P.S. Please don't tell me to do a search,becuase i have read for the last 2 months day and night, and i still can't figure it out.

vpogv · Sep 27, 2002

You need to tune the car correctly. If your EGT's just shoot up you are running way too lean, richen it up and turn the boost to 15-16psi. Watch your knock while you log as well as timing. Your EGT's should gradually increase not jump during a certain RPM range.

Blackboost · Sep 27, 2002

vpogv said:
You need to tune the car correctly. If your EGT's just shoot up you are running way too lean, richen it up and turn the boost to 15-16psi. Watch your knock while you log as well as timing. Your EGT's should gradually increase not jump during a certain RPM range.

Agree....

joereitman · Sep 28, 2002

What were your O2's, timing, knock, and pulse width with the 16G and rewired fuel pump? Check vfaq\TMO and be sure you were within normal parameters, especially O2 in the low to mid .90's.

joereitman · Sep 28, 2002

Here's some info from an older Advanced Tech discussion-

"The point I was trying to make is that everybody gets stuck thinking that you always need to keep adding fuel and that it's a safe thing to do. You don't always need to and it's not necessarily safe. The most dangerous thing to do is to add too much fuel and support detonation circumstances. Detonation will occur more easily in a rich cylinder than a lean cylinder. In a lean cylinder the fuel will atomize more fully and there will be very few "drops" of fuel that can/will detonate b4 the ignition spark. Detonation won't occur if the timing is correct and the combustion temps don't increase too high or too quickly. BUT, the problem we have is the d----- knock sensor. Our ECUs will advance timing as far as they can (on the table) until they hear knock from the knock sensor. This is not necessarily a bad thing, but it can make timing a real bear. If you're tuning in for 17deg of timing and get it close, then the ECU may try to advance to 18deg and "hear" knock and then retard it back to 15deg. Argggg! You just took one step forward and two steps back.

So, EGTs can go lower by either adding or subtracting fuel. It just depends on what fuel/air mixture you're running. Typically, we run rich of peak under WOT. Typically, as in ALWAYS. The problem is that when you run rich your cylinder heads run hotter. There's a limit to the amount of heat they can withstand. 600F and Aluminum will melt. If you keep dumping more and more fuel into the cylinders to compensate for the hot air you're pumping in from the turbo, you can end up melting your cylinder head.

NEO95GST · Sep 29, 2002

I am going to put the 16G back in and see if i can tune it better. Thanks for your help..

P.S. Will a 6cm2 housing be better than the 7cm2 housing..

I just got done putting a RSR catback on my friends 95gst ...his mods are a small 16g, walbro, stock downpipe, gutted cat, and rsr catback. We took it for a spin and it was Faster

than my car. I was datalogging his car and his timing at WOT was 3 degrees only at 14lbs of boost. I told him that is unsafe, but it was pulling HARD. Also he bypassed the stock FPR and i asked him why, he told me it ran better iwth it bypassed. I didn't believe him but he proved it to me and it was a big difference...

ChicagoGSX · Sep 29, 2002

NEO95GST said:
I am going to put the 16G back in and see if i can tune it better. Thanks for your help..

P.S. Will a 6cm2 housing be better than the 7cm2 housing..

I just got done putting a RSR catback on my friends 95gst ...his mods are a small 16g, walbro, stock downpipe, gutted cat, and rsr catback. We took it for a spin and it was Faster than my car. I was datalogging his car and his timing at WOT was 3 degrees only at 14lbs of boost. I told him that is unsafe, but it was pulling HARD. Also he bypassed the stock FPR and i asked him why, he told me it ran better iwth it bypassed. I didn't believe him but he proved it to me and it was a big difference...

His car must have been pulling timing like crazy.

NEO95GST · Sep 29, 2002

Thats correct thats what i saw in the datalogger.

kxc36g · Sep 30, 2002

Since you have a GST, please spend the $100 or so required to DYNO tune your car with your datalogger and a WIDEBAND 02. It will be the best $100 you ever spent. It took me 2 years to figure this out... don't make my mistake.

Also, before you go, make sure your plugs are gapped correctly, you do not have any boost/ exhaust leaks, your timing is correct (about 5 deg) and everything else on the car is working correctly.

Good luck,
Chris

Blackboost · Sep 30, 2002

NEO95GST said:
P.S. Will a 6cm2 housing be better than the 7cm2 housing..

A 16g with a 6cm2 housing will give you faster spool time, but less top end. The 7cm2 housing will not spool as fast as a 6cm2 housing, but will give you a lot more on the "top end" department...

joereitman · Sep 30, 2002

Blackboost said:
A 16g with a 6cm2 housing will give you faster spool time, but less top end. The 7cm2 housing will not spool as fast as a 6cm2 housing, but will give you a lot more on the "top end" department...

I went with the original 6 cm2, ported it as much as possible, and agree with James. In other words, the 6 is very "streetable".

TURBO623 · Sep 30, 2002

T-2 to a 14B turbo........what mods, if any do i need to do to make the trasision. ???? the car is basically stock i just started to fix it up. Another question has any one see a 2 intercooler set-up???? got me ..

dsm1995gst · Sep 30, 2002

TURBO623 said:
T-2 to a 14B turbo........what mods, if any do i need to do to make the trasision. ???? the car is basically stock i just started to fix it up. Another question has any one see a 2 intercooler set-up???? got me ..

Let's stay on topic.

TURBO623 · Sep 30, 2002

SORRY!!

Going from a 14B to a 16G, my car is SLOW

NEO95GST

vpogv

Blackboost

joereitman

joereitman

NEO95GST

ChicagoGSX

NEO95GST

kxc36g

Blackboost

joereitman

TURBO623

dsm1995gst

TURBO623

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