http://www.350zfrenzy.com/forum/show...&threadid=3029

 

The VQ 35 in the Z is a very tempermental motor regarding timing and fuel as you can see by looking around this sight. It's gonna take more than low compression pistons and squirting more fuel into it to make that thing last for any appreciable amount of time at 25 psi. Heard at the first dyno pull of this car" Hey what's that noise above 6000 RPM, the one that sounds like someone shaking a can of marbles. Detonation, the sound of you buying a new motor."

 

damn!! i hoped they forged everything.

 

its going to take alot to get 18G's to be happy at 25 psi too

 

Bad move on the 268s and the turbos...

Isn't going to run nearly as strong as she could.

BIG NA cams and boost don't mix - can actually loose power.

No offense to whoever is doing it... sounds like they are having a blast. Though honestly they look like they grabbed every part they could find, and asked for it to be installed - without thought-out research.

 

Aren't those 18g's only efficient up to 22psi? Also, the wastegate that comes with the kit is only designed for 1.0bar and will need a bigger spring. True?

 

usualy this is the case ..... mainly because of overlap ..turbos forcing the air in but pushing it right out the exaust valve.. do those cams have alot of overlap???? if not then hell .... might work out nicely

 

I think the 268s are fine for FI.

 

In Atlanta huh? Unless they did a bang up job I'm sure I'll see it smoking on the side of the freeway one day.

 

What makes you think that?

 

Those 18G's should hopefully be able to keep 25psi to redline. The gotta be making like 6-700 rwhp. Gonna be interesting to see how the block likes 25 psi w/ only connecting rods & pistons.

 

i give it no more than 1000 miles at 25psi

 

There aren't any cams out for the Z that are too big for FI that I know of. The Tomeis are made for either. My understanding is that they have a mid size duration (268) and a mid to small overlap. No, I don't know the exact number of the overlap but I suspect it is 112 for some reason. If you want to go by duration, the EVO guys have 272s that go good with their turbo cars. However, we know that only one aspect of the specs are not enough. Also, several people have confirmed my belief iincluding Kyle at SGPRacing. I have been doing a lot of looking around to plan my project motor as well.

 

Well I guess if you can afford to do all that, you can afford a new VQ35.

 

 

I'm not saying what they are doing is right or wrong, I really don't know the details of it (didn't read it all honestly) and don't truly know enough about it.

But one thing I've found kind of suprising is that none of the FI kits for the Z are using head shims to lower compression (or some other method; pistons, etc) which seems to be pretty standard in a lot of other applications.

Anyone know why? Just curious.

 

Show me a kit that includes pistons or any other way of lowering compression. This is news to me.

 

Well I've never seen a kit that includes pistons or head shims (per se) but it's *standard fare* for a lot of'em.

Just do some reading on the net for some of the high PSI stuff out there; like Supra's running high 20's boost; most of them shimmed the head or ran lower comp pistons.

I just thought it was fairly standard practice.

BTW: I didn't mean "kit" like pistons in a box with your tubo, lol.

Don't be so literal.

 

Well I Googled "turbo kit head shim" just for the hell of it to see what would come up, and this is more or less what I was talking about.

These guys apparently do turbo kits on MR2's, do lower compression pistons and a head shim as part of the "kit" (oh god, there's that word again!).

Anyway, sorry to confuse!

http://www.racetep.com/mr2tpart.htm

 

Top End ownz. Those were the guys I was looking to when I was planning a project 3sgte. A-one engine work.