Getting more for the MKIII- stock

[Grandavi]

This is stupid question time... but my 88 is a 7MGTE and bone stock except the rad (got it while I had coolant changed, is the KOYO aluminum one). No 3" exhaust yet, although I have 2 available on my donors. Boost is stock, the only addon related to the engine is a turbo timer (just using it for cool down).

So.. I have questions. First, I own a 87 that has a really nice 3" exhaust and Megan DP on it, boost controller and the waste gate is shimmed I believe. I get a whistle when I start out which I thought was initially the fan belt, but now I think its a vacuum leak. Did the previous owner shim the waste gate for faster spool? (all the cars I own btw are 7MGTE)

Second, to begin with, all I think I need is a boost controller (would be nice to have a boost gauge to put inside the car as well) to up the boost from stock to 10-12 psi. Correct? The 3" exhaust is a given so I wont discuss that yet, unless there is something relevant that I should know other than it lets the car breathe better...

I dont need to focus on the FCO (adding Lexus AFM, 550 cc low imp injectors, or fuel pump) unless I go with a larger turbo. Correct?

The stock BOV is fine, or should I upgrade that? (not sure if its needed for performance, looks or sound ..)

Finally.. I have a JDM Supra JZA70 rear-end (LSD), does anyone know the gearing on this? Just wondered what it is compared to the stock one in my 88 to decide if I am going to swap this in or not...

Found this...
Other features of the JZA70 Supra was the replacement of the mechanical clutch LSD with a Torsen unit. The final ratio was also changed to 4.11 compared to the 3.73 of the MA70..
so now I have to go look and see what mine is on the 88... probably the 3.73. Not sure which is more desirable.. (going to read now.. )

Thanks in advance!

[Sonyps307]

On the turbo it comes stock with a LSD with 3.73 gears

[bioskyline]

the turbo cars came with 3.90 gears for the 88 year, regardless of auto or 5spd. the non turbos came with 3.73 (4spd) and 4.10 (auto).

http://www.willdabeast.net/Supra.html at the bottom is a chart that will decypher you axle code. this code will be on the engine bay tag

on my red 88 i had when i was in calgary i was running 10-11 psi on the stock fuel system and it handled fine. once i past the 12 psi mark i hit fuel cut. that was with stock exaust installed, with the 3 inch it did ran at 15psi till i layed off the gas and blew the intake hose from turbo to i/c, hose split right in half. the stock bov is super small, and doesnt vent fast enough for more than stock. so id go with the bosch upgrade one from 935motorsports, or if your lucky at pick a part down glenmore, search turbo cars for a bigger one. i found a wrecked 911 turbo and grabbed the bov off it, but you might find some turbo'd cars with n ice aftermarket parts you can mod to fit.

for boost controller what i used was a vacuum tee fitting. just find one that fits your wastegate hose, and cut hose in half and stick the tee in. and boom, 10-11 psi with a less than 50 cent part. and it cant fail!

if you can wait a month ill be in calgary end of november and i can give you hand modding your car

[Grandavi]

That sounds wicked simple.. lol. All this time I have been putting around in my Supra thinking.. man.. this is a quick little unit. Then I buy this 87 that is running at 12 psi.. and its like night and day. The exhaust is nice, but I dont want it as loud as what it is on the 87. Nice idle rumble, but it roars so much while driving I feel like I am racing even though I am just keeping up with the cars beside me (no speedo.. so is best way to avoid tickets.. lol)

[bioskyline]

no speedo? did the spedo cable break or what? i used a gps nav unit as my speedo when the cable broke, never did replace it till my car got stolen and shreaded

and yes, i worked in a junk yard for 10 years, so i built my car with parts laying around work.

[Grandavi]

Havent had the car long enough to tell if the cable is broke or just not put on. Most of the car is a bit of a hack job although done pretty decent. Like.. now I have a problem where the door ajar light is stuck on.. but I think that may be moisture related somewhere in the electronics. I will fix the speedo cable if I start working on the car, currently it is slated to be a donor car, but my kids are very adverse to my taking it apart after I took them for a spin in it.

I dont quite understand the wastegate though. I have to research where it is on my car, and if its something I should look at upgrading (current plans are to put a 57 trim CT26 upgrade on it after its painted). I understand its purpose (mostly) but when i went to look for it, I got confused.. (I am an old fart.. so thats easy to do).

researched the boost controllers and a cheap T-type seems to be all I need to open up the turbo more.

Have been researching BOV's but some are purdy and some may have a nice sound, but I want a bit of noise when it kicks. Not sure which one is a good option really (just a simple bolt on that looks good and does the job.

The stock exhaust has issues (small ones like the turbo elbow restriction) and I have 2 cars running 3" exhausts on them now.. the 90 is the quietest so I may just swap exhausts and that problem will be solved providing it is from the turbo back. Not sure if I have a custom DP on the 90 yet as its under a car cover and I haven't seen it in a couple months. Im stuck on buying a new stainless steel 3" with DDP or using one off of my other 2 cars.

All in all though, if I drop the 3" exhaust on it with a DP (not divorced if I see it correctly on my 87), push the turbo to 12 psi, what is the HP estimate that I will be getting at the wheels? 250-265?
(with the stock fuel system and AFM)

[bioskyline]

the wastegate is what controlls boost levels. it opens and let exaust gas bypass the turbo and out, keeping it from spinning the turbo faster making more boost.

most internal wastegates using pressure from the compressor side to move the rod that activated the dump of exaust. inside the other end is a spring set to you stock boost level (useually 5-6 pounds) by putting the tee fitting in the line, it vents pressure, so it now takes 10-12 psi to move a 5 lb spring. the spring is what closes the wastegate when boost drops for shifting. pretty simple. shimming the wastegate with washers behind the spring to make the spring stiffer also works

problem is that stock our cars have the airflow meter on the intake of the turbo. meaning all the air is metered from the turbo to intake. hence why it has the recirc system so the pressure drops but air volume stays the same. with it vented to air like the hks ssq the eninge will stall as the air/fuel mix changes since all that metered air is now gone, and you run super rich. if you get the map or maft you can vent fine since air is measused after its compressed, not before.

as for exaust i had no problems running 10-11 psi on the stock exaust. it worked better with the 3 inch but you can leave the elbow in. the elbow outlet is 2 and a 1/4 and i use the megan racing dp that goes from 2.25 to 3 inch. i dont have the rest of the exasut so all i run is the dp. and it is LOUD!!!. all the ricer hondas with the bee-in-a-tin-can mufflers got nothing on me. i sound like i got a jet engine under the hood as all you hear is fan blades spinning.

as for hp gains. id think it would be around the 300 range, maybe higher. i raced a 427hp skyline and only lost by a fender length, so hard to say what i was running, but i also ran a hubless clutch.

and i want to see pics of you cars!!

[Grandavi]

If you click on my name and check out my public profile I have a gallery set up for my 90 and my 88 (they should be viewable by all...)

I dont have pics yet of the 87 because I just bought it but this link will show you its "specs" and has pictures of it
http://www.supraclub.ca/forums/showthread.php?t=4256

The 87 is very loud as well and iirc it has the Megan DP on it and the wastegate is shimmed (it screeches at take off though, not sure if thats the washers shimming the wastegate or a vac leak. It will also stutter at high revs as its stock AFM but is running (supposed to be) at 12 psi.

[bioskyline]

yeah i saw them last night, i swear ive drove past your house before casue the red one with its damage looks verry familiar.

and that is one sweet 87! i love the rims, much more sexier than mine

[Grandavi]

well.. the red one I have only owned for about 2 months (maybe 3 now). The guy had it in Saskatchewan before Alberta... and his uncle was a Toyota Mechanic (although you couldn't tell by looking at what was done to the car.. lol.

I know it was hit once in the pass rear quarter, so that quarter panel if 95% solid.. the driver side is just starting to do the typical Supra bubble shuffle with rust. Overall its a good car and I have a replacement hood and fender for it, but will have to either replace the engine or just do the head gasket (although I am leaning towards replacing because in the end it may be cheaper..)