Whats up fellas.I'm going to be running a de sleeved block with 90mm 8.3:1 compression pistons and a sr20ve head with N1 cams and I have a couple of question I hope that some body with knowledge will chime in.My first question is. How deep should the valve reliefs be?My second question is.What head gasket is available?And my final question is about the N1 cams.I read in this forum that N1 cams have to much overlap for turbo but it havent been explained theraly.Ive read of b18 running 296 duration cams on turbo and I will like to know how can I make N1 cams work on my set up because is the only cams I have available now.

1st off 90mm bore is too big for turbo, hello HG failure over and over and over.

I guess there is no 2nd of all, so I am done.

Good Luck man

I disagree. Especially at 8.3:1

Supposedly, Cosworth is making a 90mm HG and I forgot if Cometic made one or not. One thing I would recommend while going 90mm Sleeved would be the Meziere Electric Water pump setup...

I plan on running a similar build in the semi-near future. 90mm DE block w/ GTir main and piston squirter machining and som tricks, VE head, N1 cams, etc 12.5:1 CR on custom slugs. should be a nice NA build...

n1 cams for 8:5:1 compression= PISS.

just run stock sr20ve or vet cams.

I disagree. Especially at 8.3:1

Supposedly, Cosworth is making a 90mm HG and I forgot if Cometic made one or not. One thing I would recommend while going 90mm Sleeved would be the Meziere Electric Water pump setup...

I plan on running a similar build in the semi-near future. 90mm DE block w/ GTir main and piston squirter machining and som tricks, VE head, N1 cams, etc 12.5:1 CR on custom slugs. should be a nice NA build...


That is nice that you disagree, but just go ask Mazworx the issues they have had with 90mm bore, and the Falken drift team and anyother pro who has dabbled in boosted 90mm. ERL builds Falkens blocks and they only do 87 and 88mm for them. They will do whatever you want but advise against it.

Like I said good luck, the Cometic HG sucks for 90mm, esp when boosted, their HG suck anyway, no firering, WTF? SCE makes a copper 90mm HG, but you need to o-ring the block/head for that, and change oil and coolant alot since they like to mix. This issue has been beaten to death on FA. People that know know that 90mm is just too big on a boosted sr. Not enough room for proper seaing between cylinders.

Good luck

High desert......... I used to be in 29 Palms.

n1 cams for 8:5:1 compression= PISS.

just run stock sr20ve or vet cams.

8.3:1 compression pistons in a de block with a sr20ve head = 8.8:1 compression and since my block got decked a bit is going to be around 9.0:1.Why is it b18 run cams with almost 300 duration and N1 cams that are 288 duration are no good?I know sr20turbofreak used sr16 cams and made some crazy whp and they are just 8 duration lest.

Try it and see, stop having people guess for you, im sure 99% of the pople on here have not done such a thing thats why they dont know.

^^ ditto

1st off 90mm bore is too big for turbo, hello HG failure over and over and over.

I guess there is no 2nd of all, so I am done.

Good Luck man


what brought u to this conclusion?


just asking because i totally disagree but im curious to know why you think it is too big

what brought u to this conclusion?


just asking because i totally disagree but im curious to know why you think it is too big

Because it has been tried multiple times by pro teams, just read my earlier post in the thread. Don't believe me, that is fine. But you should believe shops like Mazworx, one of the leading sr20 innovaters in the states. And Falken drift teams and ERL performance. We have gone over this on FA so many times with people that want to do it.

I am by no means against people doing new things to advance our engine development, but when you got a shop like Mazworx that has there own cnc, pioneered the z32 tranny to sr20 in s chassis and races and builds sr's for a living doing the R&D to build a 90mm bore is constantly blowing gaskets and looking for a solution, then it seems that the 70th Joe Shmo to try it will have the same probs the 69 before him and the pro teams have had.

I say onward and upward, but with sensibility and prudence, not gung ho, oh my bank account is empty and car doesn't run right.

90mm will be doable next year most probably when THE h/g comes out.. I would stick with 87/88mm bore since it has been proven to handle a high amount of boost/horsepower. I have been waiting for a stable 90mm h/g for boost but none yet so 87 it is.

90mm will be doable next year most probably when THE h/g comes out.. I would stick with 87/88mm bore since it has been proven to handle a high amount of boost/horsepower. I have been waiting for a stable 90mm h/g for boost but none yet so 87 it is.

Is that the cosworth HG I heard rumors of. I know Mark at Mazworx has been working on the issue coming up with a HG just like the Apexi which is pretty much the best HG out there.

Also, just to throw this out there, 2 of the fastest and most powerful sr cars in the US are running 86 and 87mm bores IIRC, maybe it was 86.5mm.

I called Mazworx today and they recomeneded me to go no bigger than a 88mm bore on a high boost aplication.Any thing bigger I will have HG failure.They said they are trying to have some available by the biggining of next year.So I think I going with a custom 87.5 - 88mm piston.

Apexi H/G ftw, great design and would only use a big bore gasket like it. I am waiting to see what Mark comes up with.

yeah I just did 87mm bore and down the road maybe a 90mm bore. If going N/A I would do a 90mm bore with a cometic h/g at this moment in time.

So to the OP doing a 90mm bore would be awesome. If you are a able to wait and experiment with 90mm gaskets available nowand in the future then go for it. But let me say what fro said 2 of the fastest sr20s use 86/87mm bore at crazy boost levels without a problem.

Cool, again I just wanna sya not trying to rain on any parades, just dont want hard money to be wasted on what is proven not to work, for the time being with the avail materials. Once Mazworx says they are good on R&D for 90mm and they have a reliable solution, I hope you do it, because your car will be badass.

Back from the dead ......it sounds like the head gaskets are ready for this aplication now !!!

Through what company?? Apex or mazworx?

Mazworks ...and cosworth