Some may have seen the thread I started in the FI subforum. Click here. While the search for the perfect turbo fires up I'd like to also begin the search for the perfect motor. In the other thread I explained that I'm building the car to be SM legal which means it needs to be a 3.0 or smaller to be FI. Plus I like the simplicity of the 30 timing equipment. So, what I'm thinking for a fairly temporary motor is:

Buy a 30K miles DE-K for ~$500+- Sell the DE-K manifold(and heads if I can find a buyer.) Then by a 35 with a blown bottom end if I can find one. Put the heads from the 35 onto the DE-K bottom with the proper cam spacers and such. Strap it all together and run a Z33 full IM except with an adapter for a cable driven Pathy TB. Sound like an idea? Since the combustion chambers are larger on the 35 heads how terribly would compression drop? I'd like to remain as high as possible even with boost on the horrizon. I'd much rather build a low boost high response motor with good compression than a laggy high boost motor with 8.5:1 compression.

 

You should buy my rods........

 

I will someday when I build a motor. Right now I'm building a temporary setup to be in the car so I can get it running on boost with all bugs worked out. Then its time for a really nicely built setup. I'm talking forged internals, headwork, knife edged crank, crazy oil pump, etc.

As a second option if I don't really want to build an SM motor at this point could I not run a full 3.5 longblock with 3.0 timing equipment? Basically the only difference would be lack of VTC and lack of the ugly timing cover. Would that work?

 

You stated you wanted boost response rather than ultimate power in your other thread - as you already stated lowering compression (especially when it doesn't need to be lowered) does not equal good boost response. It equals more sluggish off boost and then a big surge coming onto boost - not exactly ideal for an autoX car. Infact about the farthest from ideal that you can get. Why would you do that when you want responsiveness... there's no benefit in your intended application. It'd be worse than a completely stock motor in my opinion.

 

That would be basically like a 4th gen 3.5 swap, which you can get away with for like 1000-1100$.

Have you considered going the NA route instead? The 3.5 with headers increased my trap speeds from low 90's to low to mid 100's. Is boost really worth it at 2300-2400 lbs with driver and gas? Healthy, bolt on 350z's are trapping 105-107 mph at 3300-3400 lbs raceweight. You do the math.

To me that was the big reason behind this swap. You can reach a much higher ceiling (trap speeds) with the reliablity of a stock motor and ease on the drivetrain. Not to mention the ability to put the power down. With boost I think you're looking at excessive highway speed traction issues. If you want to build a bike killer that's fine though.

I dunno, it just seems like an hardcore NA monster would be more suitable for road racing than boost. Think ITB's.

BTW you still planning on putting the motor in the dash? I might have access to a garage this winter and I'm itching for a custom tube crossmember and something not too far off from 40/60 weight distribution. The firewall would be "molded" for the V6. I think I can back it up 10 inches and still make it look professional. And that coolant line behind the motor has to be fully hidden. That would be nuts for traction and handling.

 

Whoa. Hold up Neal. I said, "I'd much rather build a low boost high response motor with good compression than a laggy high boost motor with 8.5:1 compression."

First, its my understanding that the 35 heads have much better flow rates. This would be good in all situations including boost. The problem that I'm worried about is that the larger CC's of the 35 heads will lower the compression. Is this true? If I'm wrong in thinking that then cool.

Now let me add in the fact that I like the 35 heads because it will give me the opportunity to run the complete Z33 IM. This also flows much better than the USIM and places my TB in a location that is definitely more ideal for reducing boost piping length and for the N/A time being the intake tract length.

Finally, I'm not building an autocross car. Auto-x is definitely not what I'm about. Road racing is the main purpose of the car with 1/4 mile being second.

Sorry about the confusion.

Can I ask a final question? If I decide to break my 3.0 rule will the timing chain covers and everything else associated fit onto a complete 3.5 longblock?

 

The 3.5 heads I believe have a 60 cc combustion chamber vs 46 cc for the 3.0 heads. In fact Nismo sells 12:1 compression 3.5 heads with 3.0 combustion chamber. I've heard in the past that the 3.5 heads on a 3.0 block will result in 8.94:1 compression but I could be wrong. It should logically fall in that range though.

You can go the Jime way and reinstall VQ30 Aluminum valve covers on the full VQ35, complete with the "Nissan V6 3000" plastic stuff. Those valve covers with the VQ30 timing chain should pretty much fool anybody.

You could also get a Pathfinder 3.5 so you can reinstall the 00 VI and have a complete 3.0 look. Plus it has flat top pistons (I think 10:1 instead of 10.3:1 for the normal domed 3.5 pistons).

 

When I read what you said about building an SM class car I thought that meant "Street Mod" the autoX class.

It's my understanding that the 3.5 heads flow better than the 3.0 heads too based on all I've read which is better obviously. But then that is offset by the fact that the 3.5 heads will lower the compression ratio pretty significantly. Which is better? What will the net effect on response be? I don't know enough about headwork and motor building to answer that unfortunatly. Might want to ask some professional engine builders and/or headwork guys. Might try phunk on my350z - he's built a number of Z engines and has had both stock and built engines in his turbo Z.

 

TSK TSK wish you had told me. I had acess to a set of heads from a 04 maxima 3.5 with blown buttom end that i let them scrapped. I have a set of pathfiner 3.5 heads and VK45DE heads.

 

Since nobody else is saying it I guess I will. I hate autocrossing. I think its a sissy form of motorsport. Road racing for me followed by drag.

J, you had me thinking about that all night again last night. Sadly I will not get to doing the motor in the dash thing this winter. There is just not enough funding for that. Doing that is going to involve a full frontal cage along with custom steering linkage and a Wilwood or AP Racing pedal box as the OEM brake booster will no longer have a firewall to mount to.

Oh believe me I've really thought hard about the NA idea. I know I could easily make 310+whp with a nice 12-13:1 VQ35 with extensive headwork and ITB's. But thats much more cost prohibitive than boost in short and longterm. A fully built NA race motor would be $8K+ where's I can run that same power level in a year and a half for $3K. Also, keep in mind that once the full cage is in the car dryweight without me will be around 2400lbs. Now keep in mind that I want to run a massive but tastefully done widebody that will allow me to run at least 315's in the back. R compound 315's don't like to break loose.

I do like the aluminum 30 valve covers. So thats great to know that they bolt on to the 35 heads. Or is it not a bolt on? I don't really care about the whole sleeper thing as the various noises eminating from the vehicle contradict that. Since I don't care about the sleeper thing I don't care to run the DE-K mani. The only benifit that gives me is better flow. It doesn't solve the horrible TB placement issue.

So since the 35 heads drop compression overly much I ask the question if I can somehow make the Z33 LIM fit onto the 30 heads?

One more question. Can the 35 timing cam sensor be made to send the correct signals to the 30 ECU? If so the only benifit of swapping to the 30 timing chain system would be for looks and a slight reduction in rotating mass at the end of the cams. If it cannot be made to work correctly, is the 30 chain system a direct bolt-on to the 35 longblock.

So, new idea since this isn't a full motor build at this time; how 'bout a full 35 w/ 30 chain equipment, 350Z RWD IM, DE-K topfeeds since they are much closer to the OEM flowrate as the DE's. Would that work?

 

No the 3.0 timing is specifically so you have NO wiring to do.

The other thing is traction. A 3.5 w/ 3.0 timing chain and ECU will always be easier to launch than a full 3.5 because it's all top end and the powerband is real gradual, just a sudden surge at 4k.

If you're going to boost a 3.5 in a super light 2WD car I would do it with 3.0 timing chain. Plus it eliminates the pain in @ss wiring situation of the 2k2 ECU.

And you retain simple cable-driven throttle vs the 900$ throttle body.

 

YO! WTF Zack! I was there today and noticed that motor was gone! I had my buddy totally set on buying my block to put those heads on! Now I have two 3.0 paperweights!

 

I beleive (not 100% sure) that you can use the 3.0 valve covers but you would have to use the 3.0 coilpacks or custom mount the 3.5 coils.

if you want to research this more......

 

I'm having a tough time understanding this part. Can you rephrase it please.

I'd definitely like the top end motor to help utilize the tranny. Why the sudden surge at 4K though? I thought the RWD mani was a single pleneum.

Bingo and double bingo.

Thanks KZZR. I'll definitely be looking into that a bit. I figured the coil issue might be a problem.

 

It means Tilley used the 3.0 timing chain only so he didn't have to deal with a complicated wiring situation. There is no performance advantage. I don't know for you but I like my simple, non-variable 3.0 timing chain setup. The 2k2 VTC's stop at 6000. So the higher you rev it, the less of an advantage a full 3.5 has. The difference is fairly minimal after 4000 though.

Well even with my emptied 2k2 manifold I had a noticeable power surge after 4k. Go figure.

 

I definately agree that 315's on that light of a car are going to hook up great for low-profile tires. Remember one thing though - you can't shock low profile, rock hard sidewall tires. That energy has to go somewhere and if there's no sidewall to handle it, they have to break loose or something will break.

My bro might put 17's on his car. My suggestion to him was to keep two 15-inch wheels in his trunk with hardcore drag radials on so when he wants to hook off the line (track or street) he can just throw 'em on and have some fun. They basically serve as two spare tires, too.

If my nittos don't hook hard enough I might keep two really hardcore drag tires in the trunk for ****s and giggles. Like, real tall. Stoplight race? GONE.

 

Hey broaner, pm me if you want a set of free 3.0 valve-covers to hack up, all you'll have to do is pay the shipping, I can hook you up with some 3.0 timing equipment also but not until I pull my motor (I bought a toast 3.0 to make the swap go quicker)

 

Thanks for the responses as I've been out of town for five days.

J, thats great to hear that the chain systems are interchangable. We are totally on the same wavelength. I love the simplicity of the 30 chain system. Plus it looks MUCH better than the fugly 35 chain cover.

KRRZ, thanks for the offer but I'll have to decline as I have two full sets of both chain sytems and VC's. One of which is fully polished.

 

You keep saying this but it's simply not the case.
Sure you could drill the cams or use an adapter to mimic the VTC's full retard at 6k but you'd lose a ton of mid-range and low-end. If/when you get aftermarket cams, the difference is even larger. No VTC's compromises the powerband, and not just in the low-end.



If you like the simplicity, fine. But don't try to completely discredit the technology.

 

I think the amount of discrediting is fairly minimal. We all know that the complications associated with the e-gas ECU's are just that, complications. We also all know deep down that there is a performance advantage. Some of us however choose to ignore this advantage due to the lag time(albeit minimal) on the e-gas and as I already mentioned, the extra complexity. On a boosted setup you want as few complications as possible. Same is true for race cars. The simpler the better. Thats simple^2. Thats been my outlook on all things automotive since I can remember. The technology is great but not for everyone. I should go home and count the plugs I have connecting to my motor. Let me see, I think 20 plugs is pretty close.

 

That's a real bad reason to use the 3.0 ECU! More power everywhere in the RPM band is always better if you ask me.

I've been looking at the diagrams and it doesn't look that bad at all. If you know how to wire up a 3.0 in a different chassis then you won't have any problem with the few extra wires needed for the 3.5L.

900$, what???? Is that what the dealer charges for one of those, please see your local salvage yard.

Fred

 

That's exactly how i see it.

 

if its the e-gas that is keeping you from doing a full 3.5 swap, just go with the pathfinder setup so you can have your simplicity AND the power

 

OH PLEASE about the E-gas. I bet all the wires are on 1 dumb harness anyway. e-Manage Ultimate + 3.5 ECU = OMFG. See the thread I started a while back about the complexities. I bet it is harder to find an intact main harness of an A33B then it is to wire up the car. Broaner if you can throw a VQ30 in a 240 then you can definitely run the 3.5 ECU.

JClaw's info about the full 3.5 swap skews the truth since he used Altima parts and I think he used an Altima BCU too.

 

You're wasting your time to tell you the truth. Let them think what they want to think. It's either someone thinks it's worth it or they don't. Just like you couldn't convince them that it is, you can't convince me that it's not.

 

I'll post up pics of what's needed as far as hardware and what a properly trimmed and modified 3.5L harness looks like very soon. Then everyone should be able to clearly understand what's involved with the 3.5L ECU (in a different chassis that is).

Fred

 

Ok, can we please not make my thread a cat fight please.

I'm going to speak for myself for the rest of this post.

I fully appreciate the technology of the VTC's. Still, I'm a purist. I barely even like fuel injection. LOL. These advancements are awesome for the greater comunity and if I were to buy a brand new G I'd be very greatfull for the added power.

Thanks schrale, I know I can run it but I don't know the future EMS plans for the car. There is a serious chance that I could move to a map based system at some point via a fully standalone EMS. Also partially related, I have no interior and the extra key dissable box or whatever is ugly.

The other reason for my desire to stay with the 30 timing system is the looks. Call it silly but for me form and function must co-exist. Again I'll reiterate that I'm a purist.

To tell the truth, I haven't researched the Pathy route enough to know as much as I should. Perhaps that will be an option. But the e-gas is out for me. Next winter I'll be undertaking a severe chassis remodeling project which will involve chopping it all up and moving the motor behind the front subframe. This will neccessitate an aftermarket pedal box and running an electronic throttle pedal would be tough.

All this said, I could change my mind if the benifits stack up.

For the sake of the thread, I'd appreciate it if we could all present our perspectives in an intelligent matter. I have read and understand many of your points. I'm mulling them over.

 

Maybe that would be true if I hadn't sent back the wiring box that weighted 47 pounds. As I've said in the past I'm planning on fabbing an individual throttle body system and incorporating the e-gas in there would probably be a whole lot of fun.

I rather have the 6 TB's and a hood that actually closes than e-gas and VTC.

Unless of course you can use the 2k2 ECU (and thus VTC's) with cable-driven throttle. But no one, as far as I know, has been able to do that yet.

Because I still have my second 2002 wiring harness (all the way up to the ECU plug) laying around in a box. It's from the Altima though.

So in order to use ITB's (which require a standalone like the Megasquirt due to no MAF) and VTC, I would need to wire up a 2002 ECU AND a standalone, which, to say the least, sounds ever so slightly daunting.

 

Outside of a Nissan ecu, the only option I have seen for closed-loop vtc control is the Hydra EMS. It is a full standalone that lists for about $2K. The last I heard, the Z33 application was still in beta test.

The potential for huge liability issues associated with DBW control malfunctions will keep most of the players out of the game. Unfortunately, this fact will also keep the vtc control options to a minimum because the applications are all very manufacturer specific.
(ie. there is no point in doing a Nissan VTC control system if the Nissan DBW system is also used on the same engine)

 

Reviving this because I ripped apart another 30 on Monday to get a fresh look at things.

So, does Tilley still make the adapters? And since in his thread the overlap question never got answered, anyone know about that?

 

I typed out a fairly detailed response to the overlap thing and it got erased. I won't retype it, but in a nutshell, current 3.5 swaps have 17* of overlap according to what i've calculated. The 3.0's have 6*.

 

D@mn. Thats kinda scary as I'm planning on boosting. How incredibly poorly would the 30 cams flow on the 35? Basically the only benefit of going to the 3.5 would be for displacement and slightly bumped compression. It'd be hard to calculate if the head flow and IM flow benifits would be negated by the less aggressive lift. Plus a CC design slightly more friendly toward detonation. Are there boost cams out there for the 35?

Any idea on Tilleys adapters?

 

Tilley is MIA. I wouldn't even waste my time trying to contact him at this point. You can still use the 3.5 cams, you would just have to order the spacer/adapters or cam drilling with a few degrees of retard dialed in to reduce overlap.

 

3.5 cams have 14 degree overlap
240 degree exhaust
238 degree intake.

If my calculations are correct they provide 3.5 degree advance.
The 3.0 cams have 0 degree advance.

 

What is this number based off of? I based mine off Stephen max telling me that they did it so that it's halfway between what would be full advance and full retard with the VTC. The VTC's offer 15 cam degrees (30 crank degrees) of advance/retard. The way the current 3.5 swaps are set up with either drilling or adapter/spacers is with 7.5* of advance relative to full retard. I took the cam timing values from the FSM @ full retard and subtracted 15* (since crank angle = cam angle x 2) from the values to see what the cam timing is with these swaps:

At full retard the IV opens @ 6* ATDC per the FSM cam timing specification. Advance the cam 7.5* (which is what the 3.5 with 3.0 timing equipment is set at) and the IV opens at 9* BTDC. The exhaust valve closes @ 8* ATDC. The difference between 9* BTDC and 8* ATDC is 17*. Kthx.
I'm fully aware of these duration specifications, but these numbers on their own mean absolutely nothing when calculating overlap.
This is incorrect.
Relative to what? Advance/retard is a relative term. If you have nothing to compare it to it's invalid.

Furthermore, i never gave an advance specification. I gave an overlap specification for the 3.0 which is indeed 6*. Don't believe me? Check the cam timing specs in the FSM.


ATDC = After Top Dead Center
BTDC = Before Top Dead Center

 

thanks for the info. Well aware of the Lingo. I used this to help me figure out the calculations using information from the FSM.

http://www.performore.com/technical_...ction/main.htm

I employ you to also consider looking at this alternative to figure out overlap/advance timing/retard timing. And than we can make a safe conclusion. To be honest I haven't seen anyone write on these boards of how much timing the 3.5 cams provide.

 

I was just reading your post again. LOL. Hey I'm not trying to argue with you. I think you are very knowledgeable. But, I never contested to the 6 degree overlap being incorrect. I was also just looking at the cam specs in general and not relating it to the 3.5 swaps.