compression, how high is too high on 98fuel.

[DenZel]

This question is such a dreamers question.
Firstly whats you engine build budget.
and what is the engine build for?
Who is building it and where.
Who is tuning it and where.

The difference between a Good realiable top HP engine and and hand grenade has very little to do with ports, compression, cams whos pistons you use or which rods you use.

a engine is 40% hardware 30% knowledge and 30% skill.

you need to have a set goal. and a budget which allows you to obtain it.
what i cant see is why you need to push the compression so high just to take ignition out of it..

safe compresion isnt about a number its about combustion chamber and crown design abit of correct port flow. good valve seats and a proper ignition,

A engine is a package and you need to balance all things involved.
On all our historic engines we dont run more than 12:1 really even on ELF purely becasue we cannot get a good combustion chamber design to allow higher. while the same fuel in a built up Duratec would alow a much higher compression.

Answer my questions.


P.S are you the same 13B in a MZ10 guy?

bit of an old thread...but anyway.

13b in mz10 guy???? i think i recall this person, though comparing hes posts to mine without knowing anything about me or build is a bit pre-mature.

well my dreamer engine is now at this point....

1uzfe
custom headers
8 throttle bodies
adaptronic ecu, custom fuel rail, fuel reg and bigger injectors.
w58 speed crs conversion.

and its in a 1984 supra.

still havent got my hands on pistons though....have taken the advice to wait till the engine is apart too see what bore size to go, as apparently there isnt much leg room on the 1uz?

and also i wasnt decided on my cams at that point, but now i am....i think.

i still want to go 11.5.1 , and either run 290 Duration, 10.70mm Lift cams. - what you guys reckon - good combo? and yes im aware that you must use the shim under bucket conversion (still trying to wrap my head around this - can someone explain more detail about this mod), or 294 Duration, 10.10mm lift - will this require the conversion aswell? and ofcourse ill upgrade the valve springs too. - this wont be for some time, but its good to plan ahead.

and i wont need to bother touching the stock rods...they will be fine for my application. (unless i plan to rev to 9k)

many thanks to those who kept on topic, gave advice, and told me your experiences.

[abently]

Hi denzel,

Have a look at this > http://www.trdparts.jp/english/parts_engine-3s-ge.html

That tuned Engine dyno plot, I assume, is using the 296 deg camshafts. You can see how Power & Torque isn't better till after 6500Rpm.

So with that in mind, unless you have had the Cylinder Head ported to suit a 9000Rpm limit (25m/s piston speed), I strongly recommend you keep to a 272 degree camshaft with as much lift as possible and max ramp rate (i.e. shim under bucket conversion).

[DenZel]

yeah, not too sure about the shim under bucket conversion, doesnt look like its been done too many times before, been told 3sgte and 2uz/3uz parts can be used, just not sure how much work is involved.

[ed]

have taken the advice to wait till the engine is apart too see what bore size to go, as apparently there isnt much leg room on the 1uz?

i still want to go 11.5.1 , and either run 290 Duration, 10.70mm Lift cams. - what you guys reckon - good combo? and yes im aware that you must use the shim under bucket conversion (still trying to wrap my head around this - can someone explain more detail about this mod), or 294 Duration, 10.10mm lift - will this require the conversion aswell? and ofcourse ill upgrade the valve springs too. - this wont be for some time, but its good to plan ahead.

and i wont need to bother touching the stock rods...they will be fine for my application. (unless i plan to rev to 9k)

ANY of the above combinations is going to go to 9k rpm. you will NEED different rods.

pistons - can take 40thou over only, limited mainly by gasket. you can get 60thou on the bores but whats the point if gaskets dont exist

anything over about 10.2 (or so) mm lift will require machining of the valve guides. springs are best with performance springs.

shim under bucket is mandatory

[DenZel]

so 294 Duration, 10.10mm lift would sneak in ok without using the shim under bucket?

i still will look into the shim under bucket conversion, though finding little info/conversions on the net makes me think finding a workshop in perth to do the work would be very hard.

and the early rods wont cope? based on the rev range rather than power i take it, as i know the early rods are good for a fair amount of hp.

all of this is months away (want to get the supra engineered before working the engine) but any info is great.

[abently]

Send an email of to Kelford Cams, by the sounds of it, 294 and 10.10mm of lift won't need a shim under bucket conversion, but thats beside the point. The value in shim under bucket conversion is same power with less overlap which equals better drivability.

The rods and/or rod bolts won't cope with the Rpm. But depends on their design. If they are factory forged, then upgraded bolts should be enough.

Again, I'll stress, you need to have the Cylinder Head ported to increase your RPM range and therefore take advantage of the gains to be had with the extremly large cams otherwise you won't gain any top-end and actually ruin low end power and drivability.

[mr2mark]

yeah, not too sure about the shim under bucket conversion, doesnt look like its been done too many times before, been told 3sgte and 2uz/3uz parts can be used, just not sure how much work is involved.

If 3sgte parts can be used perhaps you could do shimless buckets conversion from the 1zz/2zz like my 3sgte has. Just an idea.

[rms]

Send an email of to Kelford Cams, by the sounds of it, 294 and 10.10mm of lift won't need a shim under bucket conversion, but thats beside the point. The value in shim under bucket conversion is same power with less overlap which equals better drivability.

If you are going to run any more than the factory rev limit (6200), and have upgraded the valve springs, and have modified cams, YOU NEED SHIM UNDER buckets.

The aluminium bucket collapses underneath the shim. We have found this out the hard way !!!!!

With a decent intake system, std untouched heads and std cams and springs, the 1UZ will have around 310 bhp at 6500/7000 and run to 8000 rpm +.

294 deg cams give max power around 7800/8000 and will run in excess of 9000rpm given the right intake and valve sizes.

Our N/A engine gives max power of 534bhp at 8800 and 338 lb/ft at 7800.
BTW Torque at 4800 (where stock max torque is) is the same as stock 1UZ (270 lb/ft)

[KARNAGE]

when i had my 20 valve black top i was running 11.8:1 comp and it was fine on 98ron no detonation

[DenZel]

this 534bhp na 1uzfe you talking about, was this ever sold as an engine package, think iv seen this somewhere before?

i guess ill have to re-think the whole cams situation and power band.

cheers.

[jeffro ra28]

Custom built engines of this caliber arent usually sold as "packages".

Pretty much the only thing that remains close to stock with that particular engine is head and block castings correct rms?

[ed]

ANY of the above combinations is going to go to 9k rpm. you will NEED different rods.

shim under bucket is mandatory

perhaps i wasnt clear?

[rms]

That's pretty right Jeffro,

and Ed, I think you are clear enough - but to some people, clarity is what you drink !

[Celica RA45]

not trying to be rude ABENTLeY but you type a lot of s_it and tell people wrong ideas .you need to listen to others .and also what you can do to a 4 cyl motor is different than what you will do to a v8

[ed]

to some people, clarity is what you drink !

dont remind me of clarity! im on a booze free month!