5MGE higher compression?

[MK2inCT]

A lot of folks on here are talking about getting lower comp pistons so they can run turbo...what about getting HIGHER comp pistons...say...10.5:1 or 11:1 to bump up the power in the 5mge?

If going from 8.8:1 to 9.2:1 improved power as much as it did when they switched ratios in 84, going up to 10.5:1 or 11:1 should make it a wicked powerful engine.

Thoughts on power gains? Necessary mods to supplement?

[SupraFiend]

mods to support? Really high octanane gas would be the major thing. Keep in mind not all engines handle compression jumps as well. Yes some hondas like the s2000 have something around 11:1 compression from the factory, but these engines are designed to safely run at that ratio on premium fuel. Things such as combustion chamber & intake\exhaust port design, and engine managment can greatly affect an engines abiltiy to live safely at that compression level. I'm no expert on the subject but if toyota recomends the usage of 91 octane gas for a stock 9.2 comp 5m then I'd be a little leary about pushing the compression up much beyond that. 9.4 is about the highest I'd want to go if you plan on feeding it 91\92 octane gas.

[jbrody44]

They also changed the intake runner size and shape in the higher powered 5mge not only bumping up the compression

[Black Dawg]

On an N/A 5M, I see no reason why you couldn't run 10.5 to 1 on premium without much issue. Now running that much comp. with a turbo is just a bad idea....that would have to built as a full race engine.

[Supra Bob]

Damon Saul has a beast of a car with compression like that.. He's not sure (either that or I just don't remember exactly) what it is, but its estimated in the 11:1 range... and the car is not very friendly as a Daily driver. It will definately put a hole shot on just about any turbo out there, but in so far as the finish line, the results are about the same... with less driveability.

If you do decide to go that route, a set of 210 injectors would not hurt... the extra fuel would certainly help keep you from detenating to a point...

[cruiser]

Someone said about running a 5mge on 92 oct fuel .....in NZ we run 98 oct in our supra's and it dont worry them ( comp 9.2 ) sometimes we run a mix of 10ltrs av gas to a tank full of 98 and they realy fly and still dosnt seem to worry. this is on a mtr with 200,00klms plus on it.

so you can imagine what 175hp on a av gas mix goes like, dam quick.

[Norbie]

Be aware that the US uses a different scale for measuring octane. The US uses AKI (anti-knock-index), while just about every other country uses RON (research octane number). It turns out that 92 AKI is pretty close to 98 RON.

[justcallmefrank]

Dammit, why can't they do something normal???

[Supra Bob]

Because we're Americans, and we don't do anything normal :wink: :lol:

[justcallmefrank]

I'll pay that :D

[cruiser]

So we noticed.....you even have the steering wheel on the wrong side.

:twisted: :twisted: :twisted:

[SupraFiend]

who's got the steering wheel on the wrong side? The uk, Japan and Oz and company, the rest of the world got it right :D I guess if your a lefty it makes sense but I like to shift with my dominant hand :wink:

[justcallmefrank]

Who gets all the cool cars imported from Japan? :D

I don't know about you, but I'm a right hander, and I've MUCH rather have my dominant hand in control of the wheel, you know the thing pointing my car :roll:

[cruiser]

Hang on what do you do with THE DOMINENT HAND in a auto..???.. :P

and yes even us kiwis get the best cars xx supra's 175hp std... 8)

mind you it is a bugger to find roads long enough without towns to play on

[justcallmefrank]

Come and have a play on the Nullabor, the most boring, long flat stretch of road you will ever see :)

[SupraFiend]

oh I wasen't contending that you guys get the best cars, and lets not forget the climate too. I'd love to move down to Australia sometime, but I would miss shifting with my right hand. We got a better mk4 supra though, ours make a full 320+hp stock and doesn't have the brittle ceramic compressors :D

[cruiser]

mk4's, stop swearing.......only good Supra is of course a MK2

:twisted: :twisted: :twisted:

[SupraFiend]

take one for a good drive then try telling me that :D

I love both mk2s and mk4s, but I feel the mk2s suit me better. I can actually afford them too.

[justcallmefrank]

I still don't get this fascination with shifting with your right hand? Its a much simpler concept than steering, why leave your less dominant hand to be doing the tougher thing?

As for the Mk4, I've got a little plan for what I wanna do with that :P Oh, but you also didn't get the vvti version :D

[SupraFiend]

we got the vvti NAs in 98, or at least the states did. True, but the vvti didn't really add all that much to the car and its only available on the OBD2 cars which is something I'd rather not have to deal with.

Steering is just a left and right movement, shifting is in all directions and takes coordination (missed shift bad!), and sometimes a bit of muscle. But like I said, I could give that all up for your climate and jdm imports :D

[BillyM]

Anyone who spends more time and effort into shifting at the autox usually does pretty poorly. They think that shifting down to first in tight corners will give them better accel, which it does, though cant seem to figure out why they are always scrambling to get lined up to the next gates. It is due to concentration. I personally launch in first and go straight to second, which is where I stay. I dont have wheel-spinning acceleration out of most corners, but I do get to concentrate on my lines and car-stature. There is an exception though, a straight-in, straight-out tight hairpin. I come in as fast as possible, and shift to first during my braking, then pop the clutch as soon as I start my turn-in. Without rev-matching, it allows my rear wheels to begin braking loose, and then I use wheel-spin to rotate the car. Anyone who has autox'd on a tight course knows how much of a bitch it is to get this beast around a hairpin, the only time I EVER understeer....

The moral of this story is, its not about your shifting so much, but rather concentration on the position of the car and the lines you take in it.

--BillyM
Viva La AutoX