Bill Chase

Anyone have a totally stock axcn bin,and the right definition file to read it using tunerpro?

The 90-91 vettes used different pistons, and were rated at 250 HP, so no doubt their sa tables are different than earlier years. Thanks guys.

Tuned Performance

iTrader: (92)

http://www.gearhead-efi.com/Fuel-Inj...Information-8D

BHR

pistons are the same the heads are different vette has aluminum and much smaller chambers

vette SA is the first pic

ULTM8Z

I think the OP was referring to earlier year Corvettes (85-59) vs the 90-91.... not Vettes vs Camaros.

BHR

I have to double check but I remember the 87-89 vettes had more timing in alot of areas compared to the speed density table I posted above

ULTM8Z

Holy smoke... the 89's had a TON of spark timing...

???

iTrader: (5)

I always read the worse the head is the more timing it needs to make power. as the efficiency goes up the sensitivity to timing goes down. wot power wise

ULTM8Z

I understood the same thing. Efficient chambers dont need as much timing.

Bill Chase

Nope, guaranteed the 90-91 y body used different pistons than the previous years. This is documented, they are a true flat top with four valve reliefs, similar to later lt1 pistons, but still had thicker rings. Can be confusing because I'm part numbers that supercede the early stuff. Like if you looked today it would show the same part number for 87-89 y body as the 90-91 cars had.

Bill Chase

Yep, because they had less compression. The 90-91 l98 was a true 10.28:1 scr. They were rated higher power too.

Bill Chase

double post, deleted.

Bill Chase

Those are either auto bins, or have been modified the axcn bin is for the 1991 mn6 cars, and is the one I need. No way in hell they left the factory with that much timing at low rpm high kpa. Thanks for the response though. I need a completely stock, unaltered axcn bin bro, not just a screen shot, the complete bin.
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Bill Chase

Basing my assertions that they are different on this. From back when gm still had parts available for these engines. The rings got thinner, less dish, different valve relief sizes, ring pack moved up or down, all came into play as the c4 got older. The crevice volume, and other things combined to give the 90-91 significant more cranking compression (when new) so the unadulterated axcn bin is important for me to find. Hope I didn't come off as being a smart *** or know it all guys, thanks for the responses, I do appreciate it very much. But the pistons for a 1986-1988 y body l98 are definitely different than the 90-91 y body pistons.

ULTM8Z

Did you check the link in post #2?

Bill Chase

Yeah, for some reason it has me as banned there. Weird too, because I registered there to do some research in 2019, don't think I ever made a post.ended up doing Holley efi, and never went back. Who knows

ULTM8Z

Lol... that is weird. PM me your email and ill dig it up an send to you in a little bit.

Tuned Performance

iTrader: (92)

here is the xdf and bin

Bill Chase

Apparently i registered and never made a post. Their forum is set to autoprune bots & it assumed I was a bot. got it sorted out with an email to the admins. Thanks guys.

BHR

No worries thought you were comparing to F body yes all L98s got flat pistons in 90 compression went from around 9.7 to 10.25 for the vette, I thought you were able to get the bin from the first linked post and that there was no need to post the whole bin but yeah the last post with linked bin has the same timing table as I posted earlier from looking at other bins the manual cars do get low timing in the table at low rpm in the higher kpa range its also like this for the LT1 cars aswell