I don't notice any change in the upper rpms. It still feels the same to me above 4000rpms. Strong power from 4000-5800rpms and then the HP doesn't climb as rapidly then a noticeable drop in power occuring in the 6400-6600rpm range.

 

I'll have to see if I experience the same. What gear? Let's say 2nd gear? If I do this in 3rd gear, I'd be going close to 90+ at 6600 rpm!

Because I know you have the spacer, HR Y and revup box, I can slightly compare with me having a modded Borla. I'll call the 5/16" spacer and Crawford a "wash" for this comparision.

I do know that after my X install with the Crawford, the power is very, very linear. I used to experience a pretty big dead spot right off idle to 3k, where it would take off. The plenum eliminated 70% of that. The X took another 10-15% of that out. The V-stack took out another 10% or so. Just my estimates here. There is still a tiny bit of lag but it's worlds away from what it was before. Pretty good considering I'm on a dual exhaust and stock ecu.

 

From a full on launch, I really don't get much of that bog anymore. From a roll in 1st, there is a slight lag and then there's very strong acceleration. It only happens in MM1. In automatic mode, the lag is hardly there. I think it's the ECU questioning your intentions for a split second. It feels very much like a turbo ramping up.

Every day I get on my car a bit while merging on to the highway. However, it's rare that I ever exceed 6000rpms and usually it's just 5000-5500rpms. With my old Maxima and it's decently modded VQ30, I had to wrap it out to 6500rpms+ which wasn't a bad thing because the motor was so smooth. With the G, the power band is different and there's quite a bit more acceleration in the lower rpms. It's far easier to speed in this car.

 

So you feel this in 1st or 2nd gear? You mention automatic mode but it's hard to control the gear shifting that way. So if I hold 2nd gear, I'm supposed to feel this in the rpm ranges you describe above?

 

I can feel it in 2nd and 3rd. It's just the nature of the VQ35DE. With or without the Revup airbox, the power peaks at around 6200-6300rpms and starts to drop off. It's not like it hits a wall or something, but you can definitely feel power tailing off before you hit the limiter. I've felt this since day one of owning the car.

 

Okay, it dried out today and I had a chance to do a bunch of low to high rev runs in 1st, 2nd and 3rd gears. In MM mode so I can hold the gear.

From each gear, from low to redline, it's a steady(strong) power pull all the way until it hits the rev limiter. No drop off at all. I was careful to watch it pass the low 6,000 rpm range too. No dip or drop off. Could actually use a few more 100s of rpm from what I feel. Holding a gear at about 4,000 and then punching it is reeallly nice after the last two mods (X + RU stack).

 

My memory may be faulty on this, but I thought I read that the stock ECU programming had the engine power start to drop off just before redline in anticipation of the bigger cutoff at redline. Plus, peak HP is right at 6200 RPMs. I don't have a dyno chart handy, and I don't know how DaveB's mods look on a dyno chart, but maybe its a combination of these two that are causing DaveB's dropoff just above 6200. Jeff, based on your sig, it looks like your ECU is not stock, so maybe that wiped out the pre-redline dropoff.

 

with OEM cams it drops of about 6300 almost exclusively - regardless of ECU tune... bumping the rev limiter is beneficial for ancillary things, but not power.

This mod would not help/change the 6300 drop off.

 

Bingo. Though you can gain some additional peak rpm by using a different intake manifold.

Don't get me wrong me people, the drop in power is not really significant, but it's there. Every VQ35DE with a stock intake manifold has the same general peak HP rpm. In gears 1 and 2, the power drop off it's not near as obvious. When you're at the strip and you're holding 3rd the whole run, you'll hear and feel what I'm talking about. Nissan did a great job with the intake manifold on this car. Power might peak in the 6300rpm range, but it sustains over 90% of the power right to fuel cut. It's not like my 96 Maxima (VQ30) was with it's stock manifold which made peak power at 5800rpms and power plummented 35% by 6600rpms. My G35 still pulls hard and cleanly to fuel cut and it performs best at the strip taking it to fuel cut in every gear.

 

I dunno. I just reported what I felt. I'll certainly try it again. I know what a power fall off feels like because even my modded maxima VE30DE had it.

I wish Dave, Mike and I could get together and drive. I'm sure Mike's ride would kill all but Dave and I's mods are pretty close. Except for my crawford and my modded borla.

 

Can anyone that did the RU airbox mod ONLY chime in on their mpg asap? ie.. before they reformulate the gas?

 

Mine's unchanged. What are you seeing?

 

The Air Box had no impact on MPG's for me... i noticed a small gain when changing to a high-flow drop in, in combination with all the intake mods in my sig... the AMSOIL dry paper filter... it seemed to go from 16-17 to 18-19, 20 on a good day of the weekly day to day stuff.. did just shy of 23 on a 400 mile road trip a few weeks ago... nothing great.. just more than before with the OEM filter.

 

I'm seeing 19.5 mpg with my last few tanks. But I've done other changes (ie.. 19s w/ michelins). It's slightly better than before (19s on re050s) so I wanted to try to pin down the area of difference. Looks like the lighter tires might be the reason for the slight change.


Thanks. Looks like I need to track down the Amsoil!

 

Any coupe drivers here with this mod?