[blupastu 408w]

Hello All - sorry if this is too long.


I'm seriously looking into getting a 1987-1992 MKIII turbo. A little back ground - I've been racing (street and drag) my 1989 Mustang GT for 9 years now. Its current combo is a 408ci windsor (351w stroker) making [email protected] and 580ft/[email protected] that runs 11.0'[email protected] naturally aspirated/pump gas and [email protected] with a 125 shot. I've been using DSM's as my daily driver for almost as long. They (DSM's) used to make good sleepers, but now, every kid has one and is making decent power, thus they're no longer a sleeper. My last setup was a 1995TSi with large FMIC and ported 16G turbo which made 290fwhp. In a 2800lb car, 290hp makes for a fairly quick car. Being FWD, it didnt make a drag car, but I took it several times anyways to watch MPH. Best MPH was 108.

I would like a MKIII with about the same performance. I'm NOT looking to build a car suited for the strip, rather one for street duty that would trap 106-110mph. I assume (ass-u-me) this will require about 330-340hp and a little weight reduction. First performance mod's I'll do will be to remove the A/C and all components and remove the front and rear bumper support. This should help it drop about 50-75lbs (or more?), no? The second "mod" will be to get a set of ARP head bolts/studs and metal head gasket. I still have my SAFC/egt gauge and large FMIC from the DSM - and seeing how there's plenty of room in the front bumper (in comparison to the 2G DSM) of the MKIII, I think the FMIC will fit. I make my own exhausts (have for my last 3 DSM's), so that'll come next - a 3" turbo back exh. What else is needed to get to the 330-340hp mark?

After reading this board for the last 6mos, I kind of get the sense that a lot of people consider the 7MGTE MKIII to be fragile?!?! Is the 7MGTE something thats going to stay together for the HP level I want? I consider myself to be a pretty good mechanic (all though my profession is Quality Manager) - so all work will be done by myself.


Any and all comments/suggestions would be greatly appreciated !!! I cant wait to join team supra!

Jason

 

[outofstep]

After reading this board for the last 6mos, I kind of get the sense that a lot of people consider the 7MGTE MKIII to be fragile?!?!

Only when compaired to a 2JZ that will hit 1000 rwhp on a stock block. You can hit 500 rwhp on a stock 7M and still be safe for years and years.

350 rwhp range is NOTHING to a 7M.

I realy have no idea how you came to the conclusion that a 7M is fragile...

 

[mdr40z]

http://www.supraforums.com/forum/showthread.php?threadid=152334

 

[Rajunz]

Sounds like you're right on track with your plans. No these cars aren't fragile, they are actually pretty stout. The problem is alot of young guys with little experience buy them with 150,000+ miles on them, add a MBC and crank up the boost and then wonder why they blow a headgasket.

It sounds like you've definitely got your act together. If you do the headgasket properly, and change all of the cooling hoses (another big problem on these older cars) you should easily have a dependable platform to mod on. From there, an intake, 3" exhaust and turn up some boost and you should be close to your HP goals. An upgraded CT turbo can be had for $450.00 and that'll get you over your goals. Welcome and Good Luck!

 

[drjonez]

7M fragile? yeah right. note that my bottom end is STOCK and i road race my car 6 mo out of the year....

 

[[email protected]]

I made 520rwhp on a bone stock motor with headgasket about one year ago. The car is STOUT. Build a motor and you can see 600-700rwhp.

 

[Johnny Dangerously]

most problems you read or hear about is due from poor/neglected maintinence and high milage. of course other people from other parts of the forum (i wont give out any names) take the bad and then exaggerrate it to a great extent that would make any newcomer believe these engines are fragile.


just keep the basics handy..dont run low on oil--- if youre running higher hp, do a head gasket job---and tune it properly. Im sure you know that, however.

the 7m is a very strong capable motor..it just depends on how well you treat her

 

[Mk3_300]

The above thread is great. Here are just a couple of other details. From all that I have learned, the stock turbo is only in it efficiency range up to 14psi. You can't get to that level due to the 12psi fuel cut. The Lexus AFM/ 550 cc injectors upgrade is the most common way to get around fuel cut but for those wanting to boost at or above 12psi and don't want to go out for 550's and LEX AFM just yet...a $125(est.) HKS FDC (fuel cut defencer) will get the job done. DO NOT get the LEXUS AFM upgrade WITHOUT getting the 550's as well....if not YOU WILL RUN VERY LEAN!! (detonation)

 

[blupastu 408w]

WOW! I cant believe all the responses already. I'm glad to hear they're not as fragile as some suggest... and I think you're right - its ignorant (by definition, not name calling) people who are exaggerating things.

 

[blupastu 408w]

The above thread is great. Here are just a couple of other details. From all that I have learned, the stock turbo is only in it efficiency range up to 14psi. You can't get to that level due to the 12psi fuel cut. The Lexus AFM/ 550 cc injectors upgrade is the most common way to get around fuel cut but for those wanting to boost at or above 12psi and don't want to go out for 550's and LEX AFM just yet...a $125(est.) HKS FDC (fuel cut defencer) will get the job done. DO NOT get the LEXUS AFM upgrade WITHOUT getting the 550's as well....if not YOU WILL RUN VERY LEAN!! (detonation)

I've heard the stock fuel maps have the car running extremely rich... is it possible to lean it out with the SAFC (of course keeping a close eye on A/F and EGT's) and obtain 14psi ? I understand there are lots of variables involved - i'm just asking in terms of defeating fuel cut (with out buying more stuff).

 

[Johnny Dangerously]

if you want to slightly raise fuel cut from stock 12psi...get an upgraded fuel pump..like a walbro or somethin.

i think that can raise it to 14psi....if im wrong, someone chime in.

 

[Guest]

i dont know if i would run 14 psia on a stock fuel pump that is 10 years old

 

[drjonez]

a fuel pump CANNOT raise FCO.

 

[Johnny Dangerously]

k, thanks Jonez...I needed some good source confirmation on that one.

 

[drjonez]

FCO is based on massflow (i.e. AFM reading), NOT boost pressure, NOT fuel flow, etc. its also not fuel cut, its actually spark being cut....

 

[blupastu 408w]

right, a fuel pump is just going to supply more fuel.

If the Supra MAS and ECU works anything like the DSM, you can fight off fuel cut by leaning out the mixture - basically tricking the ECU into thinking there is less airflow going through the MAS.


Does the FCO come on due to the ECU reading a certain amout of airflow through the MAS or is it measured by the ECU in terms of PSI? If in fact its masured by the airflow readings of the MAS, then I should be able to use the SAFC to lean things out and raise the point where fuel cut is realized, no? Of course more fuel is an obvious upgrade at this point. With the DSM's the VERY first mod I've ALWAYS made was a fuel pump upgrade. Learning EFI and Boost pressure with a supercharger on my mustang several years ago, I learned the hard way about adding more boost w/o adequate fuel availability.

 

[blupastu 408w]

oops - Thanks! You answered my question before I asked it!

 

[blupastu 408w]

next question - which excuse me if its posted all over the place - I havent seen it yet -

DOES THE MKIII SUPRA USE A KNOCK SENSOR to pull timing ??? If not, I suppose an EGT gauge would be one of the first mods along with fuel and wastegate shimming?

 

[derK]

^ yes it does. Be sure to rewire those because they give people a lot of headaches.

 

[bjacques]

Yes, the stock ecu has very aggressive knock compensation.

You should be aware that the MK3 uses a Karmann Vortex MAF, similar to the DSMs to which you're accustomed.

I'd also like to say, that if you _are_ going to run a MHG, make sure to properly prep the head and block mating surfaces. If you don't feel like doing this, I'd suggest just a new stock HG with ARP head bolts. I used a MHG without prepping the mating surfaces, and it leaked as bad as a blown HG (my block's deck is a little tired). A new stock gasket handles it just fine.

You're getting involved with these cars at a very good time. This model is experiencing an excellent revival. There are new parts being released all the time. There are new fuel parts, piggyback computers, AEM ECU, turbo upgrades, exhausts, suspension pieces, you name it...

HTH,
Brendan