So we have gotten hold of a 350 Z engine and have done some preliminary flow bench work to see what restrictions if any the new engine has. First thing that’s been found is the intake ports on the new 3.5 motor flow a whole lot more then the ports on the old 3.0 engine. The exhaust ports basically flow about the same. The biggest problem we have seen so far is that when you assemble the intake and plenum together with the head the first 2 cylinders have there flow cut way back as compared to the rear cylinders. As we see it the first thing that needs to be done is a new plenum made that will not restrict the front cylinders and we are working on that [would be easy bolt on] the other thing that has to be done is to move the front strut bar so we can raise the plenum and we are working on that also. Will probably be a couple of months till all this is mocked up and tested I will post up more as we find out.

 

Thanks for the info. What would Nissan's reason be for this particular design, cost savings? Any idea on what type of gains to expect from this mod? Less than 10rwhp?

 

Hey Doug,

That sounds a little similar to the problem w/ the VG30DETT in the 300ZX, except it's fuel instead. At high boost levels, cylinders 5 & 6 seem to not get enough fuel so they tend to run lean and detonate. Also having 5 & 6 waaay back in the engine compartment where it retains much heat doesn't help any at all.

Anyway, good info, but does the strut bar *have* to modified? Is there any way out of that?

Thanks.

Michael.

 

We think it was done this way just to fit the engine under the hood with the strut bar and so it would fit other platforms

 

Don't mean to correct you on this one but the VG30DETT was coolent starved in the back cylinders if you ever seen the coolent passage in that block threw the center you would go I can't believe it didn't blow up before I did any modes. This engine is getting air starved in the front cylinders and the dyno runs we did showed the engine going rich at the high rpm level.

 

Michael-Dallas


Correct myself you were absoletley right when you said the rear cylinders were getting to hot

 

The rich condition would be something an ECU would take care of, correct? Would you assume they were running it rich to reduce the potential for detonation with lower quality fuel?

Keep us posted.

 

Early pre-production models had same intake, but no front strut-bar, so that particular item didn't factor in.

 

ZISBACK,

Do you have a web page? Where will you post updates about the new plenum? Do you have a shop? Do you plan on selling the new plenum?

Thanks.

 

We think the reason it is going rich is because the front cylinders are gitting air starved the rear cylinders are gitting more air and you run the risk of detonation if you leaned it any more. The ECU has several fuel maps in it but can't make adjustments at wot because it dosn't take into account the o/2 sensors .

 

Yes crawfordzcar@comcast.net needs updating haven't had time

Yes I will post in here with results as soon as we can

Yes we will be selling these, of course the results need to be good, but as I said we are still a couple months off from getting a prototype made and getting all the test done.

Guys thanks for all the intrest and good questions

 

Have you cc'd the combustion chambers yet?

 

Not yet will try to make time next week

 

Oh man, you had me thinkin for a while. The blown VG's that owners have posted about on twinturbo.net seem to indicate that the #5/6 cratered from detonation while the other cylinders were perfectly ok.

Anyway, this may be too soon to ask, but is there an estimated price on the new manifold?

Thanks.

Michael.

 

Thanks! By the way, http://crawfordzcar@comcast.net/ is NOT a valid web address. It's an email address.

 

Try this:

http://www.crawfordzcar.com

Regards,

iboost

 

Thanks.

 

Not yet but Iam hoping they could be made for under $200

 

Now, That's What I am Talking About!

 

Although it is nice to be recognized as an authority of many things (even on a persons credibility) based on my posts here I sometimes get some I don’t care to privately address.

I have a got 2 emails asking if this "Dougrace Zs" guy is for real. Yes he is! Those of us in the Middle Tennessee Z Club all know Doug. If anyone has any doubts I know his Z car knowledge and his Z car connections will alleviate those doubts. If you want any background go to his web site or the club's web site.

http://www.crawfordzcar.com
http://www.middletennesseezclub.com

I proudly display my Crawford Z Car Service sticker on my front windshield. (Plus, those of us in the club know it adds between 5-10 hp)