Can you use a VQ35DE exhaust manifold on a VQ30DE?
Are the ports the same size?

any idea what the gains are?

 

ports are the same, gains dunno

 

hmm...
i'm not sure about this because i don't know every thing, but in order for it to flow better wouldn't it need to be a larger diamiter?

You would thik the later model maniflods would flow better since they have more displacement ant hp. Any ideas?

It just seemed like a good place t get headers since no one else makes them for a fwd. I wonder how hard it would be to use 350zx or I35 headers.

 

Since 350Zs are RWD and the engine is oriented north south rather than east west it would be impossible to use 350Z headers. You said I35 but you mean G35, the I35 and Maxima are the same car underneath.

 

well 350z are for RWD, I don't know if it will work on a FWD car. I35 has the same engine as the maxima, vq35de

 

The ports matched the VQ30 head...

Does it bolt up the same?

 

sorry i ment G35 but i guess that sout of the question

I guess what i am really wondering is that since we can't use the 350zx or any other VQ rwd's headers, can we get gains from the VQ35 heads wich you would think would flow better since they have more exaust to move in the larger and higher hp 3.5L.

It seems like an important thing to do since the power drops after 5.5k which usualy would mean it breathes poorly. This brings me to aother qustion: Would we be able to use the VQ 35's head, intake, or varailbe valve timing?

i guess that leads back to the whole "why not swap the whole VQ35"

Just an idea

 

well the problem with the vq30de, is the non variable intake. the G35 is also a RWD car. I think that the principle is sound, better breathing better high end power. The MEVI improves high end power, with a better flowing exhaust I would imagine the only thing slowing you down is the aerodynamics of the car.

 

I wonder how much it would cost me for a 3.5L's exhaust manifold.

MIVI is a must but my prob is i have a 99' and you can't get an ecu for it w/ the higher rev limiter so it makes it next to worthless.(then again there is the same prob w/ all of these other mods i have mentioned) Any one know a way to get around this problem?

BTW i read on the nissian magazine site that the VQ can safely rev to 7.5k and our 3.0's have a sorter stroke so we should be able to go higher than that.

this one too:if i tried the vvt then i would probably need the newer ecu, that might take care of my ecu problem- in a more difficult way.

thanx for the help

 

any one?

 

Originally posted by n2o_matt
I wonder how much it would cost me for a 3.5L's exhaust manifold.

MIVI is a must but my prob is i have a 99' and you can't get an ecu for it w/ the higher rev limiter so it makes it next to worthless.(then again there is the same prob w/ all of these other mods i have mentioned) Any one know a way to get around this problem?
Well it seems that we have a similar issue with the newer ECU, although I disagree with your assesment of the "next to worthless" value of the MEVI on the current Rev Limiter, which CAN be bypassed with a S-AFC from Apexi. I guess if thats all you are looking for and were in the market to do it, you could also buy an adjustable rev limiter from Summitracing.com and set if for whatever you want too. On my Dyno, my car peaked at around 4600 RPMS (I think) with out the MEVI and with my car revlimiting at 6752 RPMS I have about 2000 rpms of use of my new toy.

BTW i read on the nissian magazine site that the VQ can safely rev to 7.5k and our 3.0's have a sorter stroke so we should be able to go higher than that
to the contrary, I've read about people begining to float their valves at 7500rpms. I think that you will have to do some internal work to run that high (I don't recall what mods they had) so maybe not

this one too:

if i tried the vvt then i would probably need the newer ecu, that might take care of my ecu problem- in a more difficult way.

thanx for the help
I would almost think that if you have a FSM you could always cut and splice the wire harnesses to fit the 3.5/3.0vq's, I believe that Mardigrasmax is already working on an engine swap for his 4th gen maxima

 

thanx for the help, i'll start looking into those rev limiter adjusters.

I'll let you guys know if I try the VQ35 exaust manifold

 

I looked in Summitracing last night they are about 120 bucks for an adjustable, but I dont know about their compatability with direct ignition. There were more expensive ones that also had digital ignition enhancers and other goodies.

 

to the contrary, I've read about people begining to float their valves at 7500rpms. I think that you will have to do some internal work to run that high (I don't recall what mods they had) so maybe not

it prob wouldn't be too hard to fix that, "just" titianium valves and spings - maybe

I would almost think that if you have a FSM you could ...

what is a FSM?

I looked in Summitracing last night they are about 120 bucks for an adjustable, but I dont know about their compatability with direct ignition. There were more expensive ones that also had digital ignition enhancers and other goodies.

How would I find out if its compatible with the direct ingnition? What is direct ingnition any way?

the current Rev Limiter, which CAN be bypassed with a S-AFC from Apexi.

I was looking at this but it says that it -

* http://www.apexi-usa.com/electronics_safc.asp

I didn't see anything about a rev limiter change.
Price $439 - a little expensive for me, expessialy when i don't know the gains. It sounds cool though.

Last one:

On my Dyno, my car peaked at around 4600 RPMS (I think) with out the MEVI and with my car revlimiting at 6752 RPMS I have about 2000 rpms of use of my new toy.

That peak is pretty low in the rpm range compared to stock which is like 5.5k. How did you get it so low? Where was it w/ the MIVI?
I know MardiGrasMax has a MEVI and his peak isn't too high in the rpm range either (but he's SCed are you?)

Thanx - i know thats alot of questions

 

As I read moore about the sumitracing pruducts, it seems like the don't by pass your current limiter - just set one if you don't have one. Maybe i'm reading it wrong, any one else know?

any other solutions to the rev limiter?

 

Only way to go past the factory rev limiter that I know of is with a JWT ECU. The speed limiter can be bypassed with apexi RSM, fields AFC, or bens mod.

 

I would think that part of the reason that the 3.5 VQ is more powerful is not only because it can flow more, but because it can force more, too. It has 500cc more displacement to create a bigger vacuum and push out greater exhaust force, so to speak. I think that the different head and exhaust is only part of it's power gain.

Food for thought

DW

 

I didn't think JWT had an ecu for a 99'

Don't you have a 99'?

 

I'm not saying that the reason it has more power is the exhaust manifold but that it should flow better than our stock one since it was designed for an engine with a larger displacement. And the same with the head - I do know that the valves are bigger and the cams are more agresive. But once you start adding these things to the 3.0 its easier to just drop in a 3.5 and just worry about getting the ecu to work.

 

Understood. But what I was trying to suggest is that the gains by putting a 3.5 intake manifold and/or exhaust manifold on a 3.0 may not be worth it simply because the 3.0 can only suck in so much, and push out so much, so to speak. The VQ as is seems to be an extremely well designed motor. Given the car's cam profile, the stock head may be optimal. Look at the fact the putting a VI on a 4th gen improves top end quite a bit, and usually the exhaust has not been tampered with in the course of that improvement. To make the VQ significantly better, that aftermarket turns to boost, be it turbo, SC, or NOS. JWT has cams which radically change the cylinder head, and even makes the VQ's idle un-stable somewhat, but the top end is said to be whole lot better, too. I also look at when the VQ30DE in the 4th gen evolved to the DE-K in the 5th gen. Nissan decided to re-work the cam profile, put on a VIAS, and that dual capacity muffler. All that pushed the car from 190 hp to 222 (or 227).

Basically, if you want to put the 3.5 exhaust manifold on a 3.0, to get the most out of it, you should really put the entire head. Of course, if you're going that far, you may as well just put the 3.5 motor. The magic is in those cams, baby

But then again, I just may be a cynic

DW

 

Thanx - I think i understand now. I guess i'm just slow sometimes. JWT cams sounds like a good idea. I wonder if you can use the 3.5 cams from the later max or even the 350z. I'm kinda getting off the subject of 3.5 headers so i'll probably just start a new thread.

 

So you have a 99, eh? Me too (99.5) Our ECU wiring harness is supposedly different than the other 4th gens but very similar to the 3.0 5th gens. This makes me think that a 5th gen 222hp motor could be swapped in to a 99 or 99.5 with relative ease.

I'm too dumb and too scared to try it, but I think it has a decent chance of working. You might have to add a hood scoop/bubble and push some of the firewall back a little, but were talking about a 32hp gain here

 

All that work for 32 hp?

Buy a turbo.

 

Oh yeah, why didn't I think of that? Let just pull that $5,000 out of my pocket and go for it.

Really though, even if you did go with a turbo, which is totally unpractical for me, the gains would still be there.

 

How much do you think you would spend trying to get the 5th gen to work in there? Just to get you 32hp.

Just seems more cost effective to mod what you have.

 

The hood wouldn't be too dificult. I can do bodywork. I don't know about the firewall though. If it had to be done, that might get tricky. But assuming I could get a 5th gen ECU and and motor for $800 (does that sound right?), I think it could be pulled off for $1,000. Cost effective? People spend $600 dollars on VI's that have a negligible effect on 1/4 mile times, so it seems like it might be cost effective.

 

Where r u gonna get a ecu and motor for $800? No way.

 

That's the part I'm not sure about, hence the (does that sound right?). I ASSume that it might be possible at a junkyard. That stuff goes pretty cheap around here.

Anybody know actual costs on one?

 

Ok, well you can get the top half of a vq30dek for 800 or less from a junk yard, its documented thats the only difference between 4th and 5th gen VQ's. the intake runner {VI} is pretty much the difference. I would much sooner put that on the car than a turbo.

I don't think any firewall work needs to be done, and the engine mounts are the same since both engines share the same lower half. New hood... not bad...32hp...sweet.

 

SLC I30t: Thank you for seeing the light.

I don't know what the first step would be in doing this. Probably seeing if a 5G ECU would plug in. If that goes smooothly and doesn't throw some crazy CEL's, it's all downhill form there.

 

try 3.5 dont waste time with 30DEK, bigger gains.
i was thinking may be you could use a 3.5 short block with 3.0 plenum?

 

While the VI may not be cost effective in the 1/4, it's definitely more suited to those who want supreme highway prowess whilst keeping the motor NA and very reliable

And, by the way, it may be $600, but it's a whole less lot labor installation than an engine swap and possible firewall work.

DW

 

If I was going to do any kind of swap I would go all the way to a 3.5 too. The hardestpart would be electronics- different sensors, plugs, ect... I don't think any kind of body work would be needed since it is the same block - just bored and stroked. The variable valve timing stuff might be a biger though. There is nothing near the firewall though.

Does any one know the real difference between the 99's and the 2000's w/ the VQ30DEK? If all it is is the head, valve train, and ecu (that is close to the same plug up as a 99) than this would prob be the best way for me to do it, since I can have a lot of down time or spent tons of money. I think we should start again at BlueBird's poast:

I don't know what the first step would be in doing this. Probably seeing if a 5G ECU would plug in. If that goes smooothly and doesn't throw some crazy CEL's, it's all downhill form there.

Good luck.