Well I put my JWT ecu in and went for a drive, I just drove around the block. Im kind of disapointed I thought I'd feel more power. Mayby It has to brake in?


Well I took it between the 7500-8000rpm , from what people said was that at that range there would be harshness and lack of power. dont flame but it seems in first, if i had the nads the car would pull to 8000rpm. The pull in first does not seem to drop off until around 7500rpm 7700 still feels good. I did not shift into 2nd when i did this just pushed the clutch in and slowed down.

 

Oh man, that would be great if u made a video of you revving all the way to 8k. Are you gonna install the mevi or u gonna put in the 2000 vi?

 

The 2000 VI will be on very soon ( this month).

If anybody wants to video come to my location and they can video away

 

Wow congrats..... 1+ on the video...

 

I hope you have upgraded valve springs and retainers. Are your going to get valve float.

 

can;t that kinda mess some things up revving that high?

 

i'd like to see a dyno.

 

8k huh. sounds like its pretty high

 

LOL WOW!!!!! id like to see that as well. i kinda get nervous revving to my stock rev limiter. i have this feeling something is gonna go wrong. is it safe to go that high on stock internals. id like to know whats safe or not when i get my ecu programed

 

sweet keep us posted man!!

 

Congrats! Keep us posted as to how it goes and update the sig

Also to the dyno, whenever you get the new manifold installed.

Any mechanically inclined folks want to comment on the potential ill-effects of revving the VQ to 8000 RPM?

 

I would really like to see this video before you float a valve. j/k
I'm rooting for you. Just don't do it too many times, it's not good for your car.

 

A stock 01 makes 222hp at 6400
So, to me, I would only want my redline to go to 7400 or less.


Anyways GREAT JOB on going weith the 5th gen VI
I would be scared to rev past 7000

 

The stock Tachs are not accurate at all on the top. You may want to get a second opinion in the form of a digital tach. (S-AFC etc.)

 

weeeeee ... valve float here were come.... weeee... heh.. j/k. I would love to see this video though. What did you do? have the ECU reprogrammed to no rev limiter?

 

7700RPM?!?

sounds like your motor took the rev to 7.7K well, good job, but as ManualMaxima said you may have damaged something internally


my reaction if I got my Max to 7.7K RPM

personally I wouldn't rev my VQ sky-high like that, if I was driving any of my dad's cars ('89 BMW 535i 3.5L I-6 and/or '89 Cadillac Allante 4.5L V8), damn right I'd be hitting redline all the time on those cars ... but from time to time I'll unwind my VQ

but, to each his own

 

If you're still running the stock manifold, I can guarantee you that your power is plummenting after ~5500rpms. I remember that my dynos with the stock manifold showed peak power at 5400rpms (182fwhp) and 135fwhp@6500rpms. There's no getting around the fact that the stock intake manifold cannot flow well above 6000rpms.

Please, please be careful with this extremely high rev limiter. Have you researched what really can happen? Valve float is not something you want to deal with. It can be catastrophic. You probably won't notice much in 1st and maybe most of 2nd, but when you start revving out the higher gears, it takes longer to accelerate through the rpms which means the valve train labors on longer. Also keep in mind that people who have misshifted and had the rpms go up to an estimated 7800-8000rpms had their clutches come a part. Keep that in mind too. You're walking on egg shells right now.


Dave

 

It won't be useless once he gets the 2000VI installed. The 2000VI likes high rpms even more than the MEVI does, I bet the power is still rising or on a plateau at 7700rpm with a 2000VI.

Some tachs are more accurate than others, dave said his car indicates 7200 when he hits the 7000 fuel cut I believe, mine has a 7200 fuel cut verified on a dyno using the signal from the coil, and my tach bounces off about 7250. So his tach may be accurate or it may not.

 

I agree with Nealoc on this one, the TQ numbers seem to fall off on the 2k/2k1 VIMS after 4500rpms, but the HP numbers keep climbing quite strongly. I still wouldn't justify taking the car to 8000rpm's though, i'd stick with the 7200rpm limit, unless i wasn't concerned about reliability at all. It's all about determining whether the tradeoff, extra power vs. reliability lies with you though, so best of luck.

LEMAR

 

Well Ive' ran the car up to 7500-7800 about 30 times yesterday still sounds smooth and feels the same.

My peak hp is at 5700rpm 197fwhp and at 6318rpm 175fwhp . My car weighs between 2680-2710 maybe this is one of the reasons why it pulls good up to about 7400-7500rpm (in first)

I have a pocket logger where i can check my digital speed ,haven't used it since ECU.

But with the 2000 vi and engine (lighter internals) Cams, titanium springs and retainers. Maybe lighter flywheel and Power steering and AC gone . Also Think that I'll get a crankshaft off carpart and have it balanced and knifedged. This is my master plan for the next 1-2 years and maybe another 150lbs more taken out.
With all of this I think the 8000rpm limit will get bumped sometimes

I will be doing a dyno at XX-tuning in CONN in a week or two. Two get numbers before the VI.

 

how long did your ECU take to arrive back from JWT?

 

I wasn't going to post this but here it goes. I waited about 8-9 weeks finally called on friday told the woman on the phone about how long it was taking . She was horrified she said the guys where at lunch and they would call when they got back. Well they did and the guy kept saying how sorry he was and that to make it up to me he would do the fastest shipping they could for free. And they did and it arrived on mon.

 

1. It doesnt give you feel me hp it maps a better air to fuel ratio
once you start to modd or go FI then you will see the difference.
2.my jwt only revs to 7200rpm, they really put your's that high.
3. thats very dangerous going 8000rpm our cars go flat after 7200
so its senseless to even try.
4. congrats on your new toy, now play safe.

 

There is no such thing as titanium valve springs. Springs are still made from spring steel.

Also, you may not need to use ti retainers. You can get VQ35 aluminum alloy retainers which are half the weight of ti and only cost about $3 each from the dealer.

 

I thought anything over 7300 rpms was seriously dangerous for the VQ?

 

VQ gurus help me out here.

1) The reciprocating weight of the VQ is quite light already therefore there's little need to add "lighter internals" plus many of the components are already covered in a drag/wear reducing compound.

2) The crank shaft is already a forged, balanced, and mostly knife-edged.

My concern about revving a VQ so high is valve float, rods weakening, spun crank bearings, and possibly a snapped crank. Granted the VQ's shortblock is very overengineered, but there has to be a limit to what it can take. I can only think of one other V6 on the market that lives it's life above 7000rpms and that's the NSX motor. I know that the 2000 VI will probably help keep power strong till the 7000rpm range, but wouldn't have Nissan extended the limiter to 7200-7500rpms if they thought it was okay? Even the 350Z/G35 is limited to ~6600rpms even though it could use a 7000rpm limiter. I don't think revving to 7000-7200rpms every once in a while is bad, but pushing that number another 800-1000rpms sounds pretty risky because that means the engine will be spending a lot more time higher in the rpms on every WOT shift. With my 7000rpm limiter, my 2-3 shift lands at ~5000-5100rpms. Kris' will land at 6000-6100rpms!!! Disregarding reliability issues, it is possible to overshoot the powerbands and I think he'll be doing it with the 8000rpm limiter. The 2000 VI offers better midrange power and slightly higher rpm performance, I don't see a need to rev out to 8000rpms.

I am curious to see the results, but I sure would hate to hear about this motor popping.


Dave

 

You don't know what "pulls" hard and/or sounds smooth to the rev limiter sounds like until you get a variable intake on there

I think we discussed this a while back, your runs where with a Dynopak, correct? That would explain the ultra high dyno numbers and why they hang on a little longer. If it wasn't on a Dynopak then I don't know what to think because 197fwhp is extremely high and power holding on that long with the stock manifold is unheard off


Dave

 

where's Steve with the cartech simulation on the optimal shift points given a 8000 RPM redline?

 

Correct,

Nissan builds all of their engines now with lightweight forged internals except for the pistons. They use cast pistons for longevity because they don't expand as much.
The VQ does have two Achilles heels, one is the valvetrain which you mentioned. The VQ30s have a heavier valvetrain and are more prone to float once you go past 7k. The VQ35 valvetrain can withstand more since it's valvetrain is lighter but it still runs out of breath before 7k in stock form.
The second issue is the strength of the rods. They are forged but are quite small and won't take very high power levels. And the rod bolts on the VQ35 can't sustain 7500rpm for much time before they stretch. The VQ30 might handle more because of it's lower piston speeds. The VQ30 also has rod studs comapred to the VQ35s rod bolts.
Anyone who wants to build a 8k engine will have to address the rod and valvetrain issue to avoid painting the track with VQ parts.

 

The racing 350z I posted in another forum with a VQ30 revs to 9000 rpm and makes peak power at 8500 rpm.

 

Doesn't the newer M3 use a I6 that revs to 9000 or 8500 rpm.

 

the 1989-1995 Ford Taurus SHO with a 3.0/3.2 V6 revs to 7200

 

Nealoc is right, when compared with my vafc my tach is only off 100rpm at most. My last dyno also confirmed this.

I just rebuilt my engine and had it balanced. I installed JWT valve springs and have an MEVI. Even with these precautions I don't want anything more than the 7200 rpm limiter. Dyno's confirm that even with the MEVI power starts to drop off past 6800 rpm. With how flat my power is from 5500 to redline I can't see needing a higher rev limiter unless you get cams. After looking at my rods and fasteners I don't want to have to rebuild it again.

With this said, I hope you won't let people like me or others stop you from trying new things. We can all hypothesize but until someone tries it we can't be sure. This was the driving force in me paying $750 for headers everyone said showed no gain. With my MEVI the headers do breathe better up top and the vafc everyone told me wouldn't work is working great.

I wish you the best of luck and keep us posted.

 

I found this for the Ti valve springs http://www.honda-performance.com/pro...nd%20Retainers Just for proof bottom of page. Iv'e heard the vq35 retainers wont last past 7200 rpm.

Well with the dyno Iv'e said it many times the day I dynoed there was a z meet there and they were putting down 228rwhp to about 235rwhp stock is this too much for a z?

 

I don't think it's so much the peak power that you got that gets me, it's the power above 6K rpms that baffles me. It just does not make logical sense that a stock 4th gen intake manifold is letting you do that.

 

I think this project is great, and as long as you build it properly there is no reason why the car shouldn't live a long, happy life at 8000rpm. I don't think it will survive 8000rpm without proper preparation however. You can always go lighter and stronger, it's just a matter of how much you are willing to pay.

 

They rev to about 8k. If you rev them much past that they WILL come apart. A VQ35 can be over reved past 9k for short bursts.

 

http://www.coilspring.com/dragvalve.html

I stand corrected. They obviously found a way to make it work. It must be some kind of Ti alloy because TI to my knowledge doesn't have natural spring properties.