Intercooler On a Stock 2.5 TI

[Vigo]

I dont think this guy is ready to talk about cals.

[tsiconquest88]

who's this?

[89spirites]

Thanks guys for all the info!!! I just got a TIII RAD/IC combo and i'm getting a BOV. I'm looking for around 170whp but I would love to get around 200whp.

[Sloride]

i know but i didnt know if the vans were setup with a different power output than the cars, thats all my point was. Cus from what i have read, the vans are 145 hp but i havent seen any of the cars t1 that low of hp? arent they all 165 or something? stock that is. As to stock the vans were 145?

I've seen the autos put down alot of tq, with the graphs looking like an X.
something to do with tq multiplication.

I Ran into a S60 shadow CSX one day with a 2.2,
we were even till about 4000 rpm then he ripped by tires ablaze.

It gets really difficult to control the mitsu with an open exaust. You kinda need to lean into the throttle. I found if i mashed the gas the boost would spike to cutout. I would set the controller at 10psi and it would creep up just under cutout by 5200 when leaning in.

for the 200whp club you will love the garrett turbo. It will spool quick and provide the air for about +240whp

[Vigo]

Well damn i thought i made a post in here yesterday but i guess it didnt post or something!! feck.

I was going to say some of the same things as Sloride.

You'll have a hard time getting 200whp out of the mitsu turbo on that car. Youd have to push it to its absolute limits and it would be blowing out such hot air that your small stock intercooler would heat soak shortly and after that the engine would be very unhappy. I'd say dont bother trying unless you got spare parts and time.

Here's what i think are the performance hold ups on an 89 2.5 spirit in the order that they matter:

1. exhaust
2. intercooler
3. turbo
4. stock computer/2 bar map
5. injectors

You've already got the first two but as mentioned you probably wont be able to easily go past 170whp with your setup, and some of the reason is boost control. The mitsu turbo has a tiny turbine section, so once its up to speed and making the required boost the wastegate has to bypass all the extra air around the turbine through a tiny wastegate opening. Basically, that wastegate orifice is too small to do the job properly after the engine is pushing more air than stock, so you usually have some boost spike on the mitsu turbo before it settles down to the actual/desired boost setting. The stock computer also makes the engine cutout if it sees over 14 psi, so you usually cant set a stock mitsu turbo any higher than about 12-13psi because anything over that it will just boost up and hit cutout over and over again. This COULD be fixed by porting the wastegate hole but by the time you're in there messing with that you might as well be replacing it with the larger Garrett T3 turbo that came on t1 cars up to 87 and all t2 cars 86-89. They're pretty dang cheap, dont lag much, and can flow enough air that the turbo doesnt become the limiting factor again until past 240 whp, as Sloride said. It could also be fixed by getting a computer calibration that moves the cutout point, but again if you're going to get a new computer/calibration you might as well get one that can read a 3 bar map sensor and get a 3 bar map sensor at the same time.

So once you've got a nice full exhaust and an intercooler on there, i would say dont do anything besides save your pennies for a bigger turbo and some monitoring gauges like a wideband o2.

And honestly, the t2 style radiator and intercooler is easy, but its not really a very good intercooler. If you EVER plan to make close to or more than 250whp, you should plan to upgrade to a nice front mount intercooler. However, the t2 rad/ic is kinda blue chip because you can always sell it again later for most of what you paid for it, or maybe more, so running it now and upgrading later is a perfectly good option.

[89spirites]

When installing a Garrett T3 turbo would I need to make any major mods to make it work? Or does it just bolt on?

[contraption22]

When installing a Garrett T3 turbo would I need to make any major mods to make it work? Or does it just bolt on?

Assuming you have the swingvalve to go with the Garrett, it's a bolt on. The only other differences are the coolant and oil lines to the turbo, which should really be replaced when installing an new turbo anyway.

[Vigo]

The lines from one CAN be modified to work with the other, but realistically if you get your turbo from a junkyard you can just grab the lines from the car it came off of. Ive seen some yards near me sell turbos for $39 and every once in a while you run across an obvious rebuild or one that feels pretty good. To some extent its a crapshoot to put a used one on because they can look fine and leak oil past the shaft seals (happened to me), but if you get a t2-style turbo and accompanying lines, it bolts right up.

Possible issues:

If you use a log style turbo, you will have to buy or make an adapter for the inlet to the compressor housing. The log style turbo has a flange and bolt holes, whereas the turbo that came on T2 cars has a compressor cover inlet that you can just slip an intake hose onto. You can buy the appropriate adapter from vendors here. The compressor cover is the only meaningful part difference between the t1 and t2 garrett turbos, the performance of either would be the same.

Also, an 89 mitsu turbo car has the wide wastegate flange bolt spacing, whereas ALL but 89 garrett turbos come with a swingvalve housing with the narrow flange bolt spacing. To make your stock downpipe fit on the narrower stock garrett swingvalve housing flange, you have to either cut or grind inward a bit on the bolt holes of the stock downpipe flange. Ive done this and its easy and works.