GS turbo project

So i just purchased my GS and looking at boosting it. From what i have gathered i need turbo mani., turbo, turbo injectors, intercooler (Srt4) and piping correct? I also see that you guys say that it will handle up to 10psi of boost reliably? I boosted a saturn i had a while back which was fun considering it was the only one here in Fort Worth Tx. at the time :wink: . I bought the wife a 89 Colt GT with the 4G61T which is a blast to drive. Only mods i did to hers was remove the aircan and dump the exhaust at the down pipe and eliminated the cat. :twisted:

has anyone boosted a GS block yet? keep in mind it has higher compression than your standard SOHC 4g64, it's not so boost friendly...

Which Model and year saturn DOHC or SOHC? and have any parts left from it? if so PM me 8)

It was a 92 SL2 loaded up. I actually sold everything. This was 4 years ago when i did it. I ran 5psi with just higher fuel pressure on stock injectors and it worked fine with no ping or detonation. They are really light and can be made quick. They just have weak diff pins that like to blow out the side of the tranny.

you can boost the GS motor.

peaople boost integra type r, and gsr motors and they ahve high compression too.

its just that you have to be careful.

and take no shortcuts.

but on pump gas you will not be able to run as much boost until you get new pistons.

i'd say you will be fine with 8 psi.
which on that motor will make a lot fo power and a shit ton of toprque

probably want to run a big 16g on it.


tuning is key here though.

<div class='quotetop'>QUOTE(DOHCstunr)</div><div class='quotemain'>tuning is key here though.</div>

as always

Tuning? If i slap the injectors(1g turbo), turbo (14b), intercooler (srt-4), and piping on what other tuning would it need to run such low boost? You think an AFC would be needed to run 7-8 psi?

an afc2 will do nothing but give you trouble.

Werd! Im trying to get the Emanage Ultimate for my carpc to hook up to.

you guys seriously have that many problems with the s-afc?

It does its job for a base tune. But if you have a nice setup with some big injectors, its pretty useless. Plus it only does fuel, cant tune for timing at all.

<div class='quotetop'>QUOTE(icu_runnin)</div><div class='quotemain'>Tuning? If i slap the injectors(1g turbo), turbo (14b), intercooler (srt-4), and piping on what other tuning would it need to run such low boost? You think an AFC would be needed to run 7-8 psi?</div>

A SAFC will work fine...just set it correctly and you are good to go. For the amount of boost you are planning it will do the job. IF anything..get the setup on and get it professionally tuned at a local dyno, I am sure they have messed with SAFC's more times you can count and at the same time you get the car better fined tuned.

the afc2 is a piece of shit.

first of all, it doesn't lie to the ECU about how much air is coming in, it lies to the ECU about the temperature of the air coming in, thus fucking with your timing ONLY. there's a glitch in our ECU that prevents the afc2 from actually adding fuel

<div class='quotetop'>QUOTE</div><div class='quotemain'>If you kept the stock Spyder ECU, It is very important that you keep a POSITIVE STFT and LTFT (Short Term Fuel Trim and Long Term Fuel Trim). The 4G64 Spyder ECU is somewhat unique in this matter. If you have a NEGATIVE fuel trim (even STFT of -5%, with LTFT at ZERO), the ECU will lean out your Air/Fuel mixture badly at WOT (wide open throttle). I'm sure the Mitsubishi engineers did this for emissions reasons, but it caused all kinds of problems when I first started tuning my car. No matter what I did to the SAFC (even added +50% air), I could not get my engine to run the proper rich A/F ratio. Thus, I leaned out the car furthur, so that in closed loop operation it was adding fuel to compensate (i.e. POSITIVE STFT AND LTFT), and all my tuning problems were fixed. This is why you MUST have an OBDII datalogger. It's the only way to see the STFT and LTFT readings.</div>

when i had my wideband in, i could play with the afc all day and add/subtract fuel. the problem was there wasn't any fuel actually be added or subtracted. i could have it at -10% across the board, and throw it up to +20% across the board, and the afr wouldn't change one bit.

it is nothing more than a toy that will cost you your motor eventually.

right before i got fed up with the afc and yanked it, i had it zeroed out across the board, and the car was running all fucked up. i hooked up a timing light and i was at 1* BTDC. shut off car. removed afc2. started car up. checked timing. 4* BTDC.

that's some scary shit. i'll never come near one again. considering that i never actually got my car to run RICH during a pull is a pretty big NO-NO for using this thing. i spent months and months trying to get an afr or 12.0 or lower. never happened.

your the first person i have ever heard not having success with the AFC. Not to question you electrical or mechanical skills but are you sure you had it hooked up right? I wonder if the ECU would compensate to run 5 psi and stock turbo injectors?? Guess i would have to buy a wideband and find out. :wink:

<div class='quotetop'>QUOTE(peanotation)</div><div class='quotemain'>the afc2 is a piece of shit. Â*

first of all, it doesn't lie to the ECU about how much air is coming in, it lies to the ECU about the temperature of the air coming in, thus fucking with your timing ONLY. there's a glitch in our ECU that prevents the afc2 from actually adding fuel</div>

if the s-afc is faking your intake temp, you wired it wrong. the wire on the ecu that you are supposed to cut so that you can intercept the signal is the airflow signal, not the intake temp signal.

about the fuel trim problem, i can't speak for the 4g64's ecu, as i haven't tried it on one, but the wire you are supposed to alter remains the same, the one for airflow signal, not intake temp.

no no no, jesus christ. i'm not the only person with this problem.

djplay....brandon.....

of course i had it wired right. to suggest something that rediculous offends me. i did have some success with minor adjustments with the afc2. i could add or subtract a few percent and would see a tiny difference in the wideband, but for actual tuning, it was nothing but dangerously lean conditions.

<div class='quotetop'>QUOTE</div><div class='quotemain'>if the s-afc is faking your intake temp, you wired it wrong. the wire on the ecu that you are supposed to cut so that you can intercept the signal is the airflow signal, not the intake temp signal. </div>

that's like asking "you sure you filled up your car with gasoline before you drove it?". c'mon people, it's not like i've been doing this for a week. it was wired fine, the airflow signal wire was the one i intercepted.

so how come it didn't work? i spent months troubleshooting every problem that anyone could throw at me. i could actually get an insanely rich condition on the wideband...but only at idle. i was idling at 10.0 afr, but during a run it refused to drop below 12.0. i even posted about it.

where was everyone then?

bottom line, it's a child's toy for the 64 user. if you want to add more than a few percent it's the wrong way to go.

show me one member or user that had perfect success with ONLY the afc2 as their tuning option on a 4g64.

no need for having a big ego, everyone makes mistakes. but you're telling me, that you spliced the airflow wire, and not the intake temp wire, and that the afc is altering your intake temps instead of your airflow, that's one amazing trick, why don't you tell me how that works?

by what you said, i'm assuming you logged the runs and changing the enrichment on the s-afc changed the value of the intake temps, not the karmen reading. if this is so, there is a problem in the wiring, you shouldn't see a change in your intake temps from the afc settings, in fact, it should be impossible for the afc to know, or change those readings.

as for where i was, sometimes i leave one hobby for another for some period of time, but i was still on aim quite a bit.

btw, i'm not claiming that it will work good for the 4g64 ecu, as i said before, my experience with the afc was on a 1g ecu with 750s, and it didn't work out for me in the end because those injectors were too big to compensate for without getting too much timing. i made good power, but i was getting unavoidable knock however, if the afc is wired correctly, it should not be able to change the intake temp seen by the ecu. if you would like me to post up the afc wiring instructions and circuit diagrams to show why, i can. i couldn't find a wiring diagram for the 7g that showed which wire goes to which sensor from the mas however, although i could figure out which pin coming from the mas is the airflow, and you could do a continuity check to see which one it is.

DOHCstunr any reason why you didnt boost the 4G64 DOHC your car came with? I seen your sig at DSM talk and it shows you are running the 4G63 :? Should i not be boosting this motor? I know the compression is a little high but for 7-8 psi and 93 octane i think it will be good.

<div class='quotetop'>QUOTE(icu_runnin)</div><div class='quotemain'>DOHCstunr any reason why you didnt boost the 4G64 DOHC your car came with? I seen your sig at DSM talk and it shows you are running the 4G63 Â*:? Â* Â*Should i not be boosting this motor? I know the compression is a little high but for 7-8 psi and 93 octane i think it will be good.</div>
well if i knew then what i knew now, i woudl ahve just swapped the ecu, and installed some forged pistons and been done.
with forged pistons, stock rods and bottom end i would have been good for 350whp with that setup. with a thick headgasket and some arp's to keep the seal.

but to get started if i did it over i would have just boosted the stock motor keeping a solid and not so aggressive tune. then jsut tuned it for as much boost as i could handle w/o knock. then after that bored me i would probably get a water injection setup and upped the boost until my headgasket popped.

then i would proceed with the forged goodness.

but i didn't know then what i know now.

back when i did my setup i didn't have anybody to help me. i had to do all the reasearch myself. would have been nice to have know sabzi back then cause he woudl ahve been able to thow feedback my way, seeing as how he was finished with his swap well before mine ever was.

towards the very end of the swap i joined these forums and met seth. me and him worked together to help solve each others problems and trade parts.

It cost me a lot initially to switch to this setup. but it was worth it.
but when i go awd i'm definatly going to wish i had stayed with the 2.4 :wink:

<div class='quotetop'>QUOTE(icu_runnin)</div><div class='quotemain'>Tuning? If i slap the injectors(1g turbo), turbo (14b), intercooler (srt-4), and piping on what other tuning would it need to run such low boost? You think an AFC would be needed to run 7-8 psi?</div>

if you "slap" these things on and expect it to run well, you're in for a big surprise. There are many different fuel/ignition management systems out there. The afc2 being the cheapest, but not the best way out there. I had the afc2 with my 660cc injectors on the 4G63t and had the same issue as mentioned with the 750's. Impossible to maintain a good tune and idle with that large of injectors. There are lots of guys on this thread and elsewhere that have experience with these. I only had mine for a couple months before taking it out for something more advanced. Listen to what they have to say, they know from experience.

so it comes down to bolt it up and watch the wideband. I am going tomorrow to look at a 1st gen turbo mani w/no cracks, turbo (14B), and 02 housing for $75. The turbo has no shaft play so we will see how it goes. I then need to work on oil lines, injectors, and intercooler.