Digsy

I have a book somewhere called "The scientific design of intake and exhaust manifolds". Its very old and takes everything from first principles. You could do a search for it, or if I can find it in the loft I'll give you the ISBN number. I had a look on the SAE bookshop website and was surprised to find...nothing!

I don't remember seeing one of those. Anyone else got one?

You didn't weld it, did you?

Yep. And overboosting.

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I think this is the same stuff my local Toyota dealers use.

It needs a power supply so I reckon it should go to +12V. I believe they earth through the aerial lead. Some of them also have an on/off switch too.

Max Power clearly states that Recaro seats are only good for an extra 50bhp.

Not trying to pee on your parade but I think that's a bit of an over simplification. Firstly, you have no idea how long those Saxos and Corsas actually last after being NOSed-up. Second, the fact that the Supra is a big 3.0 litre car doesn't really have anything to do with it. If the internals are engineered to handle X horsepower then that is what they will handle. If you want to go to X+75 horsepower then you have to either assume that the engine was designed to handle the extra, or determine what the mods are and make them yourself which I guess was your line of thinking when you started this thread off. That's why I said that if the NA Supra uses the same internals as the TT, you should be OK because we know what the TT engine can handle. In my experience, modern engines are very very seldom designed to handle anything more than the stock power output, unless there is a more powreful sister engine in the same range. Even then, manufacturers may shave a few pence off the parts price by substituting lesser components into the lower powered engine. There are enough modded J2Zs out there to confirm that the GTE is build like the proverbial outhouse, but there's always something waiting to bite you in the ass. Don't take it the wrong way - Hope it works out for you!

If you make the broad assumption that internally the J2Z-GE uses the same parts as the J2Z-GTE then the answer could well be "nothing" as plenty of BPU'd TT's seem to be turning out that kind of horsepower. I think its a big assumption though. It might be worth cross checking part numbers on parts like head gasket, main bearing shells, conn rod shells, oil pump, water pump, pistons (which probably won't be the same anyway because of the different compression ratios), exhaust valves, etc.

Current model year Celica clear sides will fit a Supra so you should be OK.

For a given level of performance out the engine will be under the same mechanical stress no matter how you go about it. What a cooler intake charge does is increase the mass flowing into the engine so you can run lower boost and reduce the risk of detonation but still get the same power. Or you can run more spark advance get more power with the same risk, or you could up the boost and the fuel and get more power that way. A colder intake charge is better any way you look at it.

Well, like I said, det can be caused by running to much spark advance, too lean a mixture or generally to hot a combustion process. Still sounds like fuelling to me. I have an AFR curve for my car at home. I'll have to look at it to see if I go rich at the top too.

Sounds like you need a bit more fuel. Why have you leaned off the fuel regulator? With the cats out you'll need more fuel if anything.

Not a bog standard NA then? Or is it an SZ-R?

WhyIoughta....

You need to run cooler, richer, or more retarded. Just like me!

Does a turbo work like a volume displacement device or is the boost pressure dependant upon the density of the air? If you replace the turbo with a supercharger with no internal compression (so it is just moving x cm3 of air from one place to another) then you have a fixed volume V of air going into the engine at a fixed pressure P, at a fixed temperature T. This gives you a mass or air M for use in the combution process. From the gas laws, PV = nRT, but nR sort or equates to mass, so you might say PV = MT (probably not strictly true but, hey). So if your intake volume is limited, V will be constant. We know you have lowered T through the imporved ducting. So to maintain the balance, either M needs to increase, or P needs to decrease. I'm not sure but I would hazard a guess that the volume of exhaust gas produced in both cases will be the same if the mass of the intake air remains the same in both cases, so if the turbo should be spinning at the same rate and M will be constant. Therefore P has to decrease, which is what you are seeing. Not sure why your boost controller isn't making up the difference though. MAYBE if you change the density of the air going through the turbo you get a different pressure out than the controller was seeing when it was set up?

Knock sensors are usually mounted in a rigid location on the block or on the head. They work by sensing the shock created by the detonation, so the key to their positioning is a solid path for that shock to travel along, from any sensor to the cylinder. If you wanted to listen for it, try the side of the block near a cylinder head bolt, or the side of the head on the intake side (to save burning your fingers!) Steer clear of the cam cover as its probably isolated from the head with a rubber mount. You should be able to hear it with the naked ear but I gues you want to be more sensitive than that.

I thikn you have to think of it in terms of mass rather than volume and pressure. Its a mass of air going in and it is mixed with a mass of fuel, then burnt to make a mass of exhaust gas. I'm pretty sure the only way to destroy mass is in a nuclear reactor so if you ignore leaks then same mass comes out as goes in. If you cool the air more in the second scenario, you could have the same exhaust mass flow with the less volume of intake air under the same manifold pressure, because the density has increased.

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All engines with closed breather systems (i.e. all modern engines) are designed to have a certain amount of oil recirculated into the intake. As undesirable as this sounds it is perfectly normal and nothing to worry about. It does sound like you had a tad more than the average (a coating on the inside of the manifold / intake tube) but now you have fitted your filters, where is the smoke coming out of, exactly? Where do the filters fit. IMHO an external oil catch can is something to be avoided unless you know you are having oil surge / carry over problems (a puff of blue smoke from the exhaust on lift off, hard cornering, braking or accelerating. Just playing advocate.

According to my EPC, prior to MAy 1996 the part number for the centre section (cats back) was the same for NA and TT. After that there are seperate part numbers for each. I have no idea what the change was or whether it means that parts made after May 1996 are not compatible across both cars. Prior to looking into it myself, I thought they would not fit, but now I'm hoping they will because I want to buy Neil Sandham's TT exhaust!

Good point. Hmmm. And it'll be pressurised air, too, on a turbo engine. Double hmmm. I know that the worst case for pulling oil over into the intake system is high engine speed with no load: i.e. max revs then lift off, this robs the piston rings of the majority of the gas loads which help them to seal on the power stroke, so some combustion gases leak past and pressurize the crankcase. Simultaneously, you pull a big vacuum in the intake manifold which will help pull entrained oil in the breather system. However, fuel cut isn't quite like lifting off because you wil still have the throttle wide open, and there will be no "bang". Also I was thinking in terms of oil getting pulled up into the cylinder rather than being pushed up into the breather system by gas leaking past the rings. I still reckon the rings wouldn't be sealing too well under these conditions though... ...or I could be barking up the wrong tree altogether.

What does the rev limiter do? Cut fuelling? If so, you'll be pulling a tremendous vacuum in the cylinder instead of having a power stroke. Both valves closed, piston expecting to be driven down by an explosion, but instead getting pulled down by the crank with no gas expanding behind it. This may draw oil laden air up from the crankcase past the rings.