What mods can be done to the VQ with out going FI to get better top end? i have a 04 5at g35 coupe with intake, TD exhaust, gutted cats, motordyne 5/16 spacer, and uprev tune (which didnt help my car much), and 3.53 pumpkin. After all these mods the car is fast 0-100 but after that it seems to die out once i hit 4th gear. What mods can i do to get better top end besides cams? would an x pipe instead of h pipe help any? any help would be appreciated.

thanks in advance!

 

put another VQ engine in the trunk.

 

I havn't tested it but I think switching out the gutted cats for real test pipes will help.

 

weight reduction, Cams, headowrk, rebuild, n20, fi your wallet is the limiting factor.

 

Nitrous would be your best bet.

 

would anybody have a comparison(isthataword) with a

spacer 5/16 or
1/2 or bigger maybe. because the 1/2 is better top end, but losses in the midrange.

or how bout coswork intake

 

On NA, probably less than 5whp.

TK

 

the gearing in your 5AT (maybe 3.9 or 4.08) would be the best help 100+. nitrous would be BAD, too much strain 100+ for nitrous, much better chance to wreck engine

 

??

 

so you think 3.9 would help after 100? how bad do you think i would be reving up at 80 mph? right now with the 3.53's im at about 3200rpm at 80mph.

 

thats up from about 3k at 80 right? probly as high as 3500, but i wouldnt think past that. obviously, the absolute best thing would be a turbo setup, but after that its cams and a good IM if you dont want higher cruising RPMs

 

4.08 gears ftw! lighter flywheel! headers & cams & UTEC at the same time! a 6 speed tranny!

 

I swapped a 3.9 onto my 5AT and acceleration past 100 has improved. At 80 I'm at 3400rpm.

 

shorter gears probably won't help top end... it helps acceleration though - I have 3.692 in my AT (3300rpm @ 80 mph)... Cams are probably the best bet for top end, but OP doesn't want that route... 1/2" spacer over 5/16" may help a little (that’s what I run - peak dyno is usually pretty good)... other than that, more Osiris tweaking?...

 

Depends on what he means by "top end" i guess. does he mean from like 6k to redline, or does he mean like over 100 miles per hour...my gears REALLY helped from 80-120. but yeah....

1/2 inch spacer, test pipes, and a UTEC with Z-tube and 3 inch mass air flow sensor and a good tune by a reputable Utec tuner will REALLY help the top end. whered you find 3.692 gears? never heard of em.

 

its Nissan OEM for a few trucks and the 07 G sedan (more commonly referred to as 3.7FD)

 

OOOOOOOOOOH! thought the 3.7 was actually in the 3.7's....not short of it. thanks for clarifying

 

would i benefit in going from uprev osiris tune to a utech? i dont understand how it is that i only got <4 hp out of a tune???? most people see atleast 12whp out of it.

 

I did Orisis and UTEC so that the factory tune would stop trying to 'adjust' around my UTEC MAF tune... Orisis pretty much locks the factory ecu to one internal map (but up to five manually selectable maps). So now my UTEC tune doesn't wander around as the factory ecu randomly flips from map to map. My logs (and performance) are much more consistent now.

 

Ttt