1.9mm Headgasket Vs Standard For reliability/Boost levels

[The Toffinator]

Is there any reliability benefits to fitting a 1.9mm headgasket during a gasket change if im planning on running more boost and a bigger turbo? Ie lower temps and less danger of detonation killing the engine etc etc if i fit a 1.9mm one?

And also what mm is the standard toyota gaskets?

Thanks

[Weyro]

I think the standard is 1mm.

Speaking from no experience lol, but 1.2 or 1.4 would be as high as i would go.

I remember speaking to a guy who said you can run 1.4bar on standard internals if you use a 1.4mm gasket.

[PaulStarletSR]

I've got a 1.9mm head gasket in my SR conversion so will be interestin to know the answer to this! id have said itd alloow u to run a little more boost if u think about it

[AdamB]

You can run more boost/ignition advance. But really there is no need to run such a large gasket. It will run like a sack of shit off boost because it would be such low compression. You'll probably be looking around the low 7:1's.

My personal opinion is the stock engine is too low compression anyway (4EFTE), you can easily get away with running 9:1 on 99 RON fuel, although the boost- compression ratio relationship depends what turbo your running, how efficient it is and what boost you want to run it at. You could run a td04 at 1 bar with a CR of 9:1 happily, it will be massively responsive and make 240whp.

A Higher CR gives an increase in HP & Torque across the whole rev range, and increases fuel consumption

[Bean]

i would just get a 1.2mm athena gasket

[Addymk2]

You can run more boost/ignition advance. But really there is no need to run such a large gasket. It will run like a sack of shit off boost because it would be such low compression. You'll probably be looking around the low 7:1's.

My personal opinion is the stock engine is too low compression anyway (4EFTE), you can easily get away with running 9:1 on 99 RON fuel, although the boost- compression ratio relationship depends what turbo your running, how efficient it is and what boost you want to run it at. You could run a td04 at 1 bar with a CR of 9:1 happily, it will be massively responsive and make 240whp.

A Higher CR gives an increase in HP & Torque across the whole rev range, and increases fuel consumption

And improves your spool time ;)

[Weyro]

how do you get a 9:1 ratio, 0.6mm gasket? standard compression is 8.2:1, on a 1mm gasket isnt it?

[Azz]

I've got a cruise 2mm hg on my 4e but haven't started it as yet

[AdamB]

how do you get a 9:1 ratio, 0.6mm gasket? standard compression is 8.2:1, on a 1mm gasket isnt it?

TRD gasket, or skim the head excessively. Make sure to check the valve - piston clearence though.

If I was to build a track motor it would be a high comp 4e with cams and a td04

[Weyro]

im guessing you would need forged internals, or would 99octane fuel keep the temps down enough?

[jayc-glanza17]

I run a trd HG on my forged engine, but run lower compression then most due to dished pistons, yet since being on the omex, I can drive very well off boost.

stock compression is very good, if raising it, 99ron or higher and a standalone is most important to help gain best tune and power..

99ron fuel has a higher threshold before det then 95, that's what the ron means.

higher octane rating less change of det.

Edited May 7, 2013 by jayc-glanza17

[Addymk2]

Although tescos 99 Ron is mixed with a lil bit of methanol, which will lower temps slightly

[AdamB]

im guessing you would need forged internals, or would 99octane fuel keep the temps down enough?

Wouldn't necessarily need forged internals, but a standalone ecu is a must.

Tbh the RON rating is pretty much useless, its the MON rating that is more important, yet this isn't published. Plus you need to know the British thermal unit (energy of fuel) to get the most of the setup. Normal pump fuel is like 13,000 BTU, yet Methanol is somewhere around 4000 BTU, hence you have to burn Meth at rich mixtures like 5:1 AFR.

Edited May 7, 2013 by AdamB

[The Toffinator]

So your saying a 1.9mm headgasket would make it very low compression and it would be very lazy off boost? I dont want to lower it a crazy amount if the standard gasket is 1.0mm, Would 1.4mm be a better compromise?

And also how do you work out the compression ratio?

Ie whats standard, what would it be on 1.2mm, 1.4mm and 1.9mm Gaskets?

Thanks:)

[AdamB]

What kinda boost you looking to run? 1.4mm will be fine, but 1.2mm will probably be more than enough.

CR = (Swpet volume + Clearence volume) / Clearence volume

If using dished pistons they are +ve, dome pistons are -ve because they deduct volume from the total volume.

You need to know the volume of the combustion chamber in the cylinder head as it varies, I believe stock is 38cc. Also 1mm = 1cc, 1ml = 1cc.

Edited May 7, 2013 by AdamB

[wickedep]

adam is right..way too thick mate. we use 1mm on our race car. compression is a little higher than adam mentioned hehe..but certainly you dont need to go as high as 1.9mm's. 1.2-1.4 would be about the max.

[H_D]

I have been running a 1.9mm headgasket on my 4e for over 1 year now.

It runs spot on.

[PaulStarletSR]

I have been running a 1.9mm headgasket on my 4e for over 1 year now. It runs spot on.

cheers bud! thats all a wanted to know instead of all this fuckin about

[AdamB]

cheers bud! thats all a wanted to know instead of all this fuckin about

It's hardly fucking about mate, it's called Physics and the Truth.

Yes it will work, and yes it will take more boost/ignition advance, but you won't get the same drive, same mpg, same HP or torque. You can't have everything there is ALWAYS a sacrifice.

[H_D]

since going forged over 1 year ago i have definatley noticed better MPG when not boosting and it drives spot on.

My compression is 170PSI across all 4 cylinders and I am also using 75mm 10cc dished pistons