I am currently running a old stage 3 hypertech chip in my 85Z with an automatic. I am using all my original intake and injectors. Just wodering if anybody knows what kind of mods were recomended for this chip? I am running a ZZ4 crate motor, Is this chip going to give me problems because of my larger displacement than it was meant for? Any help or recomendations are appreciated.

 

As I recall the stage 3 was a strip chip for off road use only. Something with removing/blocking/disconnecting the egr, as well as the 160 stat from stage 2. Might be something else, don't recall.

As far as running a 305 prom with a 350, I thought the pulse widths were different. You did not say what injectors or pressure your running, or what the block learn value is.

I am going to guess that the 305 version is going to limit you, and perhaps exhibt a lean condition. I know the fellow I bought my TPI setup off, had a 1986 305 stage 2 chip and a stock 87 350 chip. He said the 350 chip made more power. I never did use the 305 chip and traded it off, so I can't say.

I have a similar combination as you, 305 TPI setup with a 350 and ZZ3 cam.

Mark.
1985 S15 Jimmy 2WD, 350 TPI, 52mm TB, airfoil, ported upper and lower plenum, edelbrock 6089 heads, ZZ2 cam (1.6 rockers on intake), AFPR, no EGR, 1LE LT1 elbow, k&n cone, 700R4, 3.73 posi.

 

Mark, I am running all my stock 305 injection, Using around 50psi (I havent gotten to the track to dial in my F.P.?) Wouldnt my 02 sensor make up for a lean condition? Can I run a 350 chip in my 305 computer? Thanks

 

well yes the ECM will try to use the O2 to make it work, but it only has so much room to work with. Past that point it will go lean. I too have a 305 setup, but I put a 350 prom in it, and then adjusted the fuel pressure to make it "look" like the 350 injectors.

I would almost bet you that a stock 350 prom would give you more power and drivability than the hypertech chip.

There is no 305 or 350 ECM. Only the prom/chip was different, so yes you can run a 350 prom in your ECM.

Mark.

 

So I can get a chip for a 85 corvette, They only put 350s In vettes in 85.

 

I have looked at about 10 different 85(879ecm) chips, well probrably more. Everyone of them have the same fuel parameters. The only changes are mainly the timing maps. Hypertech espically runs a high number timing map. I think relying on teh knocker to compensate. I'll send along a few 85 bins if someone wants to try. I was running them but then upgraded to the 7730 for the baud rate. One thing bad with the 85 scanning tools espiaclly diacom. Its adds a ffew degrees of timing when linked so be CAREFUL!!
Every 85 bin I have is set to 15lb injectors. mainly the 85 vettes came with 24lb from the factory. I actually read myself different company commerical chips( big companys) and they all are the same for the fuel that is.
Does somebody have somthing different??
Dennis
P.s dont knock the 85 ecm. I ran a 14.4 with a off the self 99.00 performance resource chip. With even my current modded setup I ran a 12.03 with that same chip!!!! still running my 24lb injectors. Since my 7730 upgrade I did change my injectors to 30lb . But the 870 ecm is a decent ecm just the buad rate sucks.

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85 vette,383,miniram,ZF6,4.10's..best ET 11.81@117.00 60' 1.65
http://geocities.com/bowtie8

[This message has been edited by BOWTYE8 (edited September 23, 2000).]

 

Thanks for all the replys, I have very little knowledge about the functions of the chip, So im not quit following all of this. Basically I am wondering if my chip is hindering my performance or my engines internals? It is all stock 305 intake except for A.F.P.R running at about 49 psi. The chip is a hypertech stage 3 for a 85 305 camaro automatic. All ontop of my new ZZ4 long block. Any other coments or suggestions? Thanks again

 

85ZZ4-

From everything that I have seen of 305 vs 350 chip images (GM based) my answer to your question would be YES. First of all the spark curve for the 305 is completely different. The 350 chip image has less spark advance across the board. This is because of the the 305 combustion chambers. The 305 combustion chambers are inefficient at flame propogation and therefore more advance has to be ruled into the chip. The fuel curves are different too, as well as the Torque converter lock and unlock curves. I would definitely recommend beginning with a stock 350 bin and working from there.

Now - how much of a difference does this really make in terms of SOTP? Depends. Could be a lot depending on how your engine is tuned to this point. Then again - If you've played with your initial timing and adjusted the AFPR then you might not be loosing too much.

Tim

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TRAXION's 1990 IROC-Z
Best Time = 12.587 @ 107.97mph (1.710 60ftr) on the long runner setup.
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels. Stock Wheels. No Weight Reduction.
Gunning for NA 11's with the MiniRam II and Hooker LT Headers.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org