Considering modification - Toyota Nation Forum : Toyota Car and Truck Forums

Shatonapples · 12-11-2006, 12:53 PM

My 1987 Supra Turbo with 36k original miles is in pristine condition, very few things are wrong with it and it's all factory stock (with the exception of tires I guess, though that hardly qualifies as modding). I'm considering modifying the intake, exhaust, and adding an electric boost controller, but I can't decide if I should mod it or leave it unmolested.

I'm just looking for some feedback, what would YOU do?

***bgrieger*** · 12-11-2006, 01:53 PM

I say mod away. Given the history of the vehicle, I'd keep all original parts removed in case you want to go back to stock. I'd also look only to bolt on components using original bolt holes to avoid damaging what must be a very clean car. You can easily return it to stock this way.

There are a few exhausts out there that retain the stock look, while giving the performance. As a shameless plug, one of our toyotanation sponsors, Raptorracing, has a very nice dual tip cat back, and coupled with a 3 inch car cat and downpipe you'll get the performance you want and keep the unmolested look. A little rumble is the tradeoff, but one most people don't mind taking. A K&N FIPK intake is again a tried and true intake that uses factory mounting bolts, and the boost controller can sit in the glovebox to keep the control unit out of sight, while the solenoid pack will fit in the front corner under the new intake.

The components you are looking at will give you a peppy 250-275 horse at the wheels. You might also consider a recirculating type blow off valve upgrade to take a little more pressure reliably, while still keeping the . The factory ones are a little flaky when the pressure rises. I like the new greddy ones myself, as they can be used with adapters to attach to the stock intake system ports, eliminating the need for set of pipes.

My suggestion, tighten the headgasket down a little (search here or on any supra site for the known head gasket issues and the resolution), fix the few things you note are wrong, and enjoy 10-12 psi. Many people are quite happy taking it to that level and leaving it there, but it really depends on what you decide you want out of it.

Jeeves · 12-11-2006, 03:49 PM

As far as I'd always known, Bob correct me if I'm wrong, Stock bolts were not to be retightened due to their 'elasticity' and inability to keep from stretching.

***bgrieger*** · 12-12-2006, 08:50 AM

Not designed to and whether you can get away with it are 2 different things. Most people wouldn't do it the way I would. I'd personally pull the head and replace the gasket and use new bolts over just a retorque, but every time I suggest it someone bitches about me being too anal and how their brother's, dog's, best friend's mother did it and it held up fine. The retorque is a catch 22 at best...tighten it down and the gasket fails maybe 20% of the time from the stress, or don't retorque and probably kiss it goodbye before too long as well.

Now for the bolts, you're right on. Though, according to Reg Reimer's experiments back in the day, the factory torque really doesn't get them in the elastic range anyhow, so it may be that at stock torque, they haven't been stretched in the first place and may be fine for a retorque. I don't like to take the chance, but if you're experimenting with a retorque rather than a replacement, I wouldn't spend the money given the chance to have to spend it again.

Shatonapples · 12-12-2006, 09:38 AM

I appreciate the input. I'm thinking I'll start with a couple of the ideas mentioned here in a couple of weeks. I would like to admit, I'm not very knowledgeable about cars. I know a few things here and there, but, in general, I'm fairly clueless. I'm going to look into replacing the head gasket because I've heard a lot about them in relation to these mark III supras.

Thanks again for all the help!

***bgrieger*** · 12-12-2006, 12:40 PM

Depending on your finances, if you are considering a replacement gasket, you might consider replacing it with a metal gasket, though the engine basically has to come out to prep it and guarantee it will perform properly. It would be overkill if you never cross the 12 PSI mark and stay with the CT-26, but gives you flexibility in case the modification bug gets hold and you want to take it to another level after that.

The upside is that done correctly, and torqued to 70ft/lbs, it goes from being the achiles heel to being pretty much the most bullet proof part. If you are sure you won't go beyond the upgrades listed here, a new composite Toyota gasket with the 70ft/lb torque spec will likely do quite nicely for you, and generally only needs the head to visit a machinist.

Shatonapples · 12-12-2006, 02:33 PM

I see. I am considering buying an additional car so that I don't have to be in a time crunch during the time that it takes to replace the head gasket. It sounds to me like you're suggesting I take the engine apart myself (which would be excellent, I would like to be less dependent on mechanics for things like that, and I know some people who could help me out with it).

How long would you expect the car to be down if it was being taken apart by a novice and some of his less than novice friends? I'd guess somewhere between a week and a month. I appreciate you humoring me, and even moreso, the help!

***bgrieger*** · 12-12-2006, 07:42 PM

In a rush, I can pull the engine in about 4 hours with a friend...but I've done it a few times. You could in theory have it done in a weekend if need be, but if you want to go slow, clean everything and reassemble very carefully, it might require a week or 2 depending on your schedule. Just removing the head will take nearly as long as the whole engine will, and is more of a pain to do on the car (believe it or not). You would also require an engine hoist.

Jeeves · 12-12-2006, 09:59 PM

I've pulled the engine in 1 hour, 40 mins. That was my top time so far.

My first ever time, I did it with people who had done it before. And it took us two weekends to fully replace the engine. That didn't deal with any mechanical work, just a JDM swap.

Shatonapples · 12-13-2006, 06:27 AM

That sounds cool. I was thinking, replace the head gasket, put a new exhaust (got any recommendations?), new intake, and then a boost controller, in that order. Also, I'm going to have to put the car on a lift to put a new exhaust in, won't I?

I'm just trying to figure out exactly what the plausability of the mods are.

***bgrieger*** · 12-13-2006, 10:57 AM

check the vendor section or the supra area for a user named raptorracing. A sponsor, he has a new line of exhaust parts. If you search the supra area here, you might even find a picture of it. You can install an exhaust with the car on stands only. No lift required. If you prefer big name exhausts, there are plenty of shops that carry them as well, from HKS and Blitz. There are also some other shop branded systems available from other retailers

Jeeves · 12-13-2006, 06:14 PM

Quote:

Originally Posted by Shatonapples

That sounds cool. I was thinking, replace the head gasket, put a new exhaust (got any recommendations?), new intake, and then a boost controller, in that order. Also, I'm going to have to put the car on a lift to put a new exhaust in, won't I?

I'm just trying to figure out exactly what the plausability of the mods are.

That's your problem right there. Head gasket you can't just pull and replace. To do it 'properly' you idealy want to machine both the head and block surfaces to a near mirror finish (30RA's or so). It's not something you can just do with a razor blade and brake parts cleaner.

I'd also suggest something more along these lines:
Intake
Exhaust
Boost Controller
S-AFC
Wideband

It's been said, but it bears reiteration. 12PSI is the fuel cutoff for the stock injectors. Without an FCD (BADBADBAD) or a proper setup, you can't duck this limitation.

As for exhausts, there are LOTS of them, depends on what you're looking for. 3" Full pipe, cat-less, 3" pipe, stock look, etc...