ecm/engine build question

[4.3fiero]

Hey guys, got a couple questions for you. Go easy on me, I am slowly learning all this sy/ty and turbo stuff.

I'm not a sy/ty owner, rather I am another Fiero guy. I have a '95 4.3L vortec with 96+ true vortec heads that I am swapping into the car, and I want to eventually turbo it (car weighs roughly 2700, goal is mid 11 sec car, about 450 rwhp according to online ET/HP calc). I will be building my own intake using weld on bungs and universal fuel rails and about 48-55lb injectors. I know the sy/ty ECM is a 1227749.

question one: can I go to the junkyard and get ANY 749 ECM, or does it HAVE to be from a sy/ty? can I swap the chip out? TBIchips.com sells a sy/ty chip, i think (have to double check).

question two: would it be better to try to figure out MegaSquirt for the whole thing, rather than try to retrofit a 749 syty ECM into a non-syty vehicle?

question three: the '412' cam i keep reading about is what part number at summit? will it go good with a stock TBI until i get the turbo setup built?

final question: what compression should I build the engine for, given my mid 11 sec goals? I want the car to remain streetable more than i want to break into the 11s, and not tear itself apart. i will do the 4 bolt splayed mains and cyro treat stock crank. my weak link will be the trans anyways.

sorry if this has been posted a million times, still trying to find my way around the forum here.

thanks!
~Chris

 

[dgoodhue]

Re: ecm/engine build question

I'm not a sy/ty owner, rather I am another Fiero guy. I have a '95 4.3L vortec with 96+ true vortec heads that I am swapping into the car, and I want to eventually turbo it (car weighs roughly 2700, goal is mid 11 sec car, about 450 rwhp according to online ET/HP calc). I will be building my own intake using weld on bungs and universal fuel rails and about 48-55lb injectors. I know the sy/ty ECM is a 1227749.

vortecfiero has done a syty turbo swap, he might have more insight for you. Traction might be an issue, are you try to do 11 on street tires or with some sticky tires? 450rwhp would have a 3500 # Syclone in the high 10's.

question one: can I go to the junkyard and get ANY 749 ECM, or does it HAVE to be from a sy/ty? can I swap the chip out? TBIchips.com sells a sy/ty chip, i think (have to double check).

question two: would it be better to try to figure out MegaSquirt for the whole thing, rather than try to retrofit a 749 syty ECM into a non-syty vehicle?

question three: the '412' cam i keep reading about is what part number at summit? will it go good with a stock TBI until i get the turbo setup built?

final question: what compression should I build the engine for, given my mid 11 sec goals? I want the car to remain streetable more than i want to break into the 11s, and not tear itself apart. i will do the 4 bolt splayed mains and cyro treat stock crank. my weak link will be the trans anyways.

ECM can be from any car, infact you can repin a 730 or 727 ECM. Megasquirt not sure if it would be easier or not, I have never convertered to a 749. The 749 does have a lot of DIY tuning support. 412 is a comp cams number. IF you were to look up Chevy 4.3 V6 cams, it would be pretty obvious. You might need a differnt cam if your 95 4.3 is a balance shaft motor. Typically the normal rebuild put compression around 8.5:1 The some talk about using higher compression pistons and pushing the compression up around 9-9.5:1

 

[vortecfiero]

Re: ecm/engine build question

Id do the 3800 swap if i had to do it again lol but i love my setup

question one: can I go to the junkyard and get ANY 749 ECM, or does it HAVE to be from a sy/ty? can I swap the chip out? TBIchips.com sells a sy/ty chip, i think (have to double check).

yes to the 7749 ecm
id use a stock chip to get things working

question two: would it be better to try to figure out MegaSquirt for the whole thing, rather than try to retrofit a 749 syty ECM into a non-syty vehicle?

stick with the 7749
I just made a new harness for it which took about 3 hrs using the plugs from a syty harness,
the fiero firewall plug and the syty ecm plugs

question three: the '412' cam i keep reading about is what part number at summit? will it go good with a stock TBI until i get the turbo setup built?

here is a excel spread sheet that outlines common builds
http://www.flipdrive.com/file/a3c9cd71dfa707c0989b4da6c487.xls

final question: what compression should I build the engine for, given my mid 11 sec goals? I want the car to remain streetable more than i want to break into the 11s, and not tear itself apart. i will do the 4 bolt splayed mains and cyro treat stock crank. my weak link will be the trans anyways.

id go for around 8:1 but someone else may chime in here

feel free to email or pm me if you have any questions

do you post on Pennocks ?
http://www.fiero.nl

 

[vortecfiero]

Re: ecm/engine build question

nudge for update ?

 

[4.3fiero]

Re: ecm/engine build question

been too cold to do much on the car. I wouldnt be posting updates here anyways, it's all over on pennocks and on my site.

 

[vortecfiero]

Re: ecm/engine build question

been too cold to do much on the car. I wouldnt be posting updates here anyways, it's all over on pennocks and on my site.

what is your screen name on pennocks ?

 

[stuartlittle]

Re: ecm/engine build question

I have a 95 4.3 block that I was building for boost. I started at $500 for the engine then tore down etc etc. Machinist stole my cam and didn't do some of the work I paid him for. Now I'm selling what I have because of life hardships getting in the way of finishing the engine.

I have a 95 Crank turned and polished 10/10
Rod and main bearings for the crank... Sealed power
ARP Main bolts & ARP Rod bolts.
K Rods with Zolner 030 Hyperuretic pistons for 8:1 CR
Sealed Power rings
Blocks been Cleaned, Bored & honed 030 with new cam bearings and freeze plugs.
Heads have been untouched
2000+ intake without injectors
I have everything that cam off the engine during tear down except the machinist kept my cam.
Yours $500

Can provide pics.