Look like that poor little Rotrex has to work it as* off trying to push air through a small pipe at the out let to fill the air to air cooler and then to big intake pipe to a motor with valve overlap. But then 390 wheel horses is a lot of horses already.

 

lol how many times have we gone over this...

 

I'm guessing Staples missed Tony's long post about this issue

 

I don't see the VVEL being that dynamic. It would have to be doing adjustments while opening the intake valve every cycle. The VVEL can't adjust that fast.


Link?

 

I did, where's the post?

 

Fast Intentions Long Tube Headers are here! - Nissan 370Z Forum

Scroll to bottom of first post.

 

I just read Tonys post.

Shumby, if there really was an exhaust leak or pressure leak like Tony wrote, why didn't GTM try to reinstall the FI long tube headers and see what happens? How long do you think the stock cats will hold up with the added pressure of the supercharger feeding air through them?

 

That's the post I was waiting for! Looks like I'm four days behind on the forums now. Nice to see someone spell it out.

 

We were able to maintain 8 psi of boost on our 370Z with stock exhaust and our 2.5'' cat back exhaust as well, the car did better with the cat back on it . as for the test pipes the will effect the torque results more then boost .

Sam

 

^What I'm saying is with shumbys car, after the exhaust leak/boost leak was discovered and fixed, would the FI LTH and CBE result in added gains over the stock cats and catback?

Are those stock parts capable of handling so much exhaust pressure in the longterm?

 

This. I'm curious as well...

 

you guys mis under stand the boost leak was not a leak at all. it was a small amout around the maf sensors and only seaped out at 20 psi when tested. this was really a non issue. BUt again showes how much attention to detail the installers at GTM have

 

Just goes back to my VQ37VHR bottom end/VQ35HR top end pipe dream

 

Thanks Shumby, and trust me I'm not smashing on GTM by any means because I plan on going with their supercharger one day. And Sam, I'm sorry and do not mean any offense.

I'm just curious as to why the LTH had such a negitive effect on the boost and supercharger... And Tony is saying that it was not the problem. Also Shumby, what exhaust did you have on before you went to GTM? It's just strange that you have to run OEM cats and exhaust with the supercharger. But them again, what do I know, because I'm not professional. I only ask because it's curious to me.

GTM does great work and definately know their stuff, and hopefully continue to push the limits even further.

Shumby, I hope you are enjoying your new beast.

 

Conventional thought would say that the exhaust valve closes before the intake valve opens. That would be (relatively) true on a low-rpm engine. However, with the RPMS that the VQ37 runs, the exhaust valve actually is still open when the intake valve opens (referred to as "overlap" since the window they are open overlap with each other). When NA, this isn't an issue, as the head is generally designed so that the intake air isn't lost to the exhaust valve because there is negative pressure in the cylinder. However, when FI becomes involved, the pressure in the cylinder is positive, so the air will look for a place to escape. There is air coming from the intake valve, so the exhaust valve is where it goes (along with a pressure loss).

Less air = less fuel (or too rich) = less power.

Unfortunately, there's no way to adjust the valve timing with VVEL here (yet), so GTM compensates by adding a restriction to reduce loss, which ultimately nets more power.