Why does this feel like turbo lag???

[blackmax23]

Ok, my 99 max has awesome mid-range/top end, but absolutely no low-end torque. It'll jump off the line, pause from 2000-3000, then at 3100, puts you back in your seat. I have an auto, which doesn't help my cause at allll, but my car doesn't pull whatsoever until 3100 rpm. Does this have anything to do with my cams? It sounds like it bogs when i get on it before 3100 rpm's. I was thinking it's my transmission cuz the gears are just so damn long, but I don't know. It seriously feels like I have turbo lag! It unloads and pulls hard from 3100 on, but absolutely nothing before. Anything I can do to fix that?

[rxm6]

Anything I can do to fix that?

Put in a 5-spd

ok seriously though....not too much. Check to see that you timing is good/timing chain is in good working order. That is what killed me for a while. I really didn't know anything was wrong until I was driving up a mountain road and i was next to a sheer cliff and a slight tinkling echoed off the wall. A new tensioner later, I have slightly better acceleration. Other than that though...you are stuck with what you've got. The auto doesn't allow for too much performance unfortunately.

[Mike G]

To be honest with you, it sounds like a lack of low end torque possibly due to lack of big system exhaust back-pressure. Don't quote me though on this one, I'm still getting my feet wet on the performance attributes and upgrade pros vs. cons with the Nissan/Infintis.

--Mike

[DjNikos]

Eh, I got the same problem. Its the timing of the transmission. It is made to run like that. Dont forget, unless you do a valve body mod, your transmission is set on a luxury shift rather than that hard racing shift. That could be it. Speaking in terms of quarter mile, the valve body mod shaves anywhere from .5 to .75 of a second off your track time so im assuming that mod would help.

[coolhand]

I had the simular problem with my 95 Max 5spd. Lukewarm from idle to about 3k. I added my Warpspeed y-pipe and 2.5 cat and that improved my low end torque from idle to 2k greatly ( it hits the 3k sweet point faster I noticed ). Is you y-pipe stock? Lets say this, my first to second shifts are DEFINITELY stronger.

[maxhopper]

Adding the y-pipe will even out the low end power band.

[mtcookson]

due to lack of big system exhaust back-pressure.

Back pressure somehow got attributed to adding low end torque because people would put on larger exhaust systems and notice a loss of low end. What's actually happening is velocity is decreased causing the lack of low end (higher back pressure won't be seen till higher in the rev range). Back pressure is always bad and will always decrease power over a good flowing system.

Basically you want it small enough for velocity to be good but large enough for good top end flow. The problem is... you can never really have both unless you could make some sort of variable exhaust system, which can be done but would be complex and heavier overall. If one wanted to, I could see doing a "dual" exhaust system but one with a smaller pipe and one with a larger pipe. Smaller pipe for the low end then have an electric valve open the larger pipe for the top end likely using an rpm switch.

Really the best way to setup your exhaust system is to design it for the type of power you want. You can have a happy medium where you can something like good low end to mid range power or mid range to high end power but it would be pretty difficult to have a "perfect" exhaust system for all of the ranges. For a turbo setup though... you almost can't too big.

[blackmax23]

Yeah, you guys all make good points. I know the transmission limits the potential of my vq, and it's geared awfully, but I def. think that my y-pipe is the biggest reduction of my power. I have a dual exhaust which was done by my buddy who works at cole muffler and is a genius when it comes to getting the most power of your exhaust, so I don't think that's the cause, especially because it was like this before I put my dual exhaust on. The timing is fine, there's just an awful lag of power, but hopefully a new y-pipe will right this wrong, or at least make it better! I'm worried about trippin a CEL code with a new y-pipe though, should I worry about that or no?

[DjNikos]

Yeah, you guys all make good points. I know the transmission limits the potential of my vq, and it's geared awfully, but I def. think that my y-pipe is the biggest reduction of my power. I have a dual exhaust which was done by my buddy who works at cole muffler and is a genius when it comes to getting the most power of your exhaust, so I don't think that's the cause, especially because it was like this before I put my dual exhaust on. The timing is fine, there's just an awful lag of power, but hopefully a new y-pipe will right this wrong, or at least make it better! I'm worried about trippin a CEL code with a new y-pipe though, should I worry about that or no?

as long as your O2 sensors go on fine, you shouldn't throw codes. However, I think what you might want to do is a valve body mod for your transmission. I heard cuts roughly .5-->.75 seconds off your quarter mile. and it keeps your transmission cooler thus giving it longevity

[blackmax23]

Yeah, I was thinking about doing the VB mod, but there's a couple issues with that. One, you need a transmission cooler because the transmission will heat up much quicker and to increase the life of it and to keep it from overheating, the transmission cooler needs to be included. Two, is the fact that it's not my shifts that is the issue, it's the lack of power from 3100 rpm's and below. It surges forward at 3100 and keeps pullin hard til redline. I can hear it building up from idle to around 3k rpm, then the power (and sound) after 3100 is awesome, but I'm hoping a new y-pipe will help that low end, which one to get is a different story.

[mtcookson]

you need a transmission cooler because the transmission will heat up much quicker

A transmission cooler would definitely be good to get, however, the valve body mod does just the opposite. Slow shifts are what builds up heat. The valve body mod makes the shifts quicker actually causing a reduction in heat buildup due to less slipping of the clutch for a smooth, luxury type shift.

[blackmax23]

You def. need a transmission cooler with the aggressive shifts. Yes, with the VB recalibration, it will shift much quicker rather than focusing on the luxury aspect of the shift, but the harder/quicker shifts heats up the fluid faster. Maxima.org explains below (from their Max FAQ's page).

What does the valvebody recalibration do and why do I need a transmission cooler?

The Valvebody (VB) recalibration is a mod for your auto transmission that will give you quicker, firmer shifts (which eliminates the weak point in the auto transmission: switching between gears). Normally, the auto transmission is calibrated to give you nice, slow shifts so as to ephasize luxury over performance. With a recalibrated VB, your shifts will be quicker and harder thus giving you faster times on the track. In addition to the performance advantages, a recalibrated VB will exert less wear on the transmission. Slow shifts will put more wear on the transmission components. A recalibrated VB may allow your transmission to actually last longer. However, the recalibrated VB does require the use of a transmission cooler. This is because the faster, harder shifts will heat up the transmission fluid quicker. The VB mod is said to eliminate up to .4 seconds in the quarter mile. Check out Level 10 or MobileTek Racing for more information.

[rxm6]

Just as a follow up...on vqpower.com their is a how to on how to make a manumatic setup for our cars. Basically allows you to use the cruise control buttons to shift your automatic...like a paddle shifter sort of. I personally think this is great and to be honest, i'd love to have an automatic that i can control when i feel like it and just set it back to auto when i'm crusing. The problem is that their is only 4 gears...whats the point. Well, I did some searching and I found this place called bowler transmissions. They are a hot rod shop and so they won't mess with our cars...but they can take a transmission and, using the existing bell housing, convert it to have more gears. They could take a 4-spd and convert it to a 6-spd. How awesome would that be for our acceleration? Right now I'm trying to find a shop around here that will do that and see if they will do it on my car. I'm sure its probably really expensive to do..but think of the potential performance gains.