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VQ35DE swap progress (now with VIDEO)

Posted: 28 Oct 2007 09:33
by xlr8r
UPDATE:
Finally put together a quick video, enjoy:
Once I figure out how to embed it I will do so.

http://www.youtube.com/watch?v=kl75pIjbOL0


Well I was originally going to wait to post up my progress when I was further along, but I'm currently at a crossroad & need a little input on how to mount up this engine, so look for my questions at the end of this post & please provide your input.

So I'm currently swapping a VQ35DE from a 2006 G35 into my Dime along with performing several other mods: R200 conversion, better fuel system with a surge tank, modding the rear LCA's so I can hopefully fit some 225's w/out flaring, etc. I'm finally getting around to mounting up the engine & I have a decision to make. The tranny is the cause for most of my grief, because it's rather large, especially at the back just in front of the shifter it gets fatter & has at least 8" of tranny below the output (where the driveshaft fits in). This makes ground clearance an issue as well as output height in relation to the Differentials height. I'm fairly new to RWD's so some of my questions stem from my minimal research & dealing with driveshafts.

As I currently have it mounted, I have opened up the back portion of the trans tunnel so I can get it up so the tranny hangs out around 3" below the bottom of the floor boards, so the bottom of it will be about equal with the bottom of the exhaust pipes. This puts the trans output 2-3" higher than the differential flange. The distance between them is 44 3/4". This would make the driveshaft angle approx 3°. As it currently sits the engine has a slight slope backwards of 1-2°. I'm assuming this is acceptable, but if it is problematic someone let me know. I can get the engine lower & leveled out, but have to push it forward to do that. This would provide me with better clearances for the headers, & hood fitment/intake manifold design, but worse clearance for the radiator & my rack & pinion would have to mount underneath the crossmember (which means I would need to find a super narrow rack if I don't want bumpsteer).

The engine-
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A temporary engine mount-
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Current R&P clearance-
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So I'm trying to decide what approach to take. I'm hoping just getting all of my thoughts out will help me come to a conclusion but would like to see what you guys think. So here's my questions:

1. Driveshaft- is 3° of angle at both ends acceptable? The diff can be mounted at a slight angle to minimize the difference on the back end if needs be, correct? This might starve the already oil starved front pinion bearing though.

2. Would a 2 piece driveshaft be better? by making the front portion have a more extreme angle but minimize the angle on the back section?

3. Should I leave the engine where it's at (back & higher) with a slight slope, or drop it & go forward to level it out?

If an even more extreme angle at the driveshaft is ok, then I could potentially raise the back end of the trans even higher, leaving the engine at it's current location.

So hopefully you can make sense of my ramblings & provide me with some helpful input. Thanks

Posted: 28 Oct 2007 09:46
by benz-tech
I believe- and the best way to confirm this is to call a driveshaft rebuilder- that the angle of the trans output and differential flange need to be the same. even if the drive shaft has to angle up or down to reach either end. so if your engine angles downward 1-2* i think you would need to raise the snout of the diff to approach that angle. imagine a vehicle with a live axle moving up and down out back, the driveshaft tilts up and down as it moves, but the key is the angles of the diff flange and trans are the same.
pretty sure of this but its been 10-15years since i delt with this issue so my facts might be a little off.

Posted: 28 Oct 2007 10:33
by vgwagon
Here is a link to a guy that put one into a z31 300zx http://www.z31performance.com/forum/vie ... &sk=t&sd=a

Don't know if it'll help but you could ask him any questions I'm sure.

Posted: 28 Oct 2007 10:50
by xlr8r
Thanks, I may have to hit him up with some ?'s

One thing I just came to realize is that if I was to leave it as it currently sits, with the engine sloping back 1-2°, that means the angle at the trans-driveshaft will actually be closer to 1-2° not 3°, & then I could get the diff to match as well. It seems with either mounting option I'll have similar driveshaft angles which are both fairly minimal & hopefully doable.

Posted: 10 Dec 2007 10:51
by El_Nino
any updates

vq

Posted: 10 Dec 2007 11:15
by clean71
i was going to do this swap do to me getting a free motor,but decided not to because of to much fab work......good luck and i would like to see it when its done.

RE: vq

Posted: 10 Dec 2007 11:45
by xlr8r
I've been collecting some important parts (the BIG stuff better arrive this week, like the EMS, headers that better fit, shifter relocator, etc.) then I'll get busy again & probably make most of my headway over the Christmas break. Lately I've been chipping away at the the non-engine related items like my modified rear LCA's & the R200 diff.

The fab work as far as mounts are concerned is fairly minor. The trans tunnel is going to take a little massaging though, or should I say cutting & welding. The intake manifold is going to be a bit more involved & I still haven't decided what approach to take. I do luckily have a Bro-in-law with a CNC shop that will make me a few intake Mani flanges, per the CAD drawings I've already drawn up, that I will then weld my manifold to.

I'll hopefully have some update pics around the end of the year.

RE: vq

Posted: 10 Dec 2007 13:01
by iknowwhoyou_r
nice.

heard you talking bout this big project to me awhile back.
glad to see it happening so soon.

if you ever in need of another 2 hands let me know.

Posted: 10 Dec 2007 14:40
by El_Nino
I assume the int manifold will not clear the hood and thats why youre doing a custom one?

which R200 are you using?

Posted: 10 Dec 2007 14:56
by xlr8r
A stock intake mani actually would clear the hood (I think) it however will not clear the firewall/wiper motor because of the elbow on the back of a stock VQ manifold. I can't decide whether to do a single plenum intake mani, a dual plenum/dual t-body manifold, or try some Itb's (very pricy, $2000 min even if I diy). It will probably be one of the first two options because I want to keep the possibility of throwing some boost at if I determine the rear tires can handle it.

I have a 3.7 ratio diff from a 86 Z31 (has the 12mm ring gear bolts needed for the LSD) that I'm going to put an OBX helical LSD into. I've already replaced the weak links in the OBX diff & just need to put it in the rebuilt diff & line things up. I'm also using a finned diff cover from a Z32 since they are more plentiful & look better in my opinion. I originally was going to use a 4.11 ratio R200 but decided I want better highway cruising RPM's & feared the 4.11 would make getting traction even more difficult on 225 tires (I hope I can fit some 225's w/out flaring the fenders).

Posted: 10 Dec 2007 15:13
by 510-Trevor
If it was just the wiper motor in the way, you could relocate it: index.php?name=PNphpBB2&file=viewtopic& ... iper+motor

Posted: 11 Dec 2007 12:00
by xlr8r
Thanks, for the link.
If it was mainly a matter of just the wiper motor I'd just remove it entirely, but it's mainly the fire wall that's the issue. I may decide to modify the firewall in order to use a stock manifold, since that would be the easiest approach. I'd rather not cut up the firewall if I can avoid it though. We'll see when I get there, I'm leaving the manifold decision for last.

Posted: 11 Dec 2007 12:51
by hang_510
what about utilizing the empty cowl as part of the intake?
easy if doing the 'down under wiper'...

Posted: 11 Dec 2007 14:45
by mesojdm
reverse intake manifold? Ive seen it done numerous times on WRX's. If not...Id do a little chop in the firewall...you would only need like 5"X5" square knockout to clear the ELBOW on the manifold(if thats all thats hitting)

Posted: 11 Dec 2007 15:32
by xlr8r
Reversing it wouldn't work for a few reasons, but I think I'm beginning to warm up to the idea of cutting out some of the cowl &/or firewall if needed. I'll have to take a closer look at it when I put the engine back in & see if it's doable. Thanks for the input/thoughts guys.

If it seems like it will work w/out too much trouble I may have to save up for a Cosworth Intake Manifold. It's a similar shape as stock but is a beauty & takes care of all the problems a stock manifold has (like the air getting to cylinders 1 & 2 being restricted).