nismology

iTrader: (8)

There are 42 teeth on the main sprockets so 360*/ 42 teeth = 8.57*. With that said, it's not a good idea to change the cam timing like this. All the sprockets need to be in perfect synchonization for the ECU to be able to do it's job properly.

95naSTA

iTrader: (10)

Why would it make the ecu unhappy?
I'm just thinking in the case of the exhaust cam, instead of having to redrill another hole you could adjust it 17.1 or 34.3 crank degrees.

nismology

iTrader: (8)

Because the cam position sensor reads off of the front intake cam sprocket.
Yea, i guess you could mess with the exhaust cam timing that way but it's not as straightforward as inlet cam timing so i'd be careful with that.


BTW, the 8.57* assumed you were talking about the intake cams. The exhaust cam timing would change a lot more since the exhaust sprockets have substantially fewer teeth.

KRRZ350

iTrader: (29)

so I'm lost then, I thought the 3.5 VI also tuned the intake runners length to take advantage of the resonance supercharging effect, so it is just a variable port design that opens additional high-end ports? how can that be since it's not on the lower manifold or head? if it is lengthened runners like the de-k than I don't see how the intake cam timing effects the rpm of that effect since it delays the opening of the intake valve AND the closing so the pulse wave would still start and return to the valve at the same time for a given rpm, sorry if I confused the hell out of you nismology like I just did to myself, I just need help to understand the 3.5 VI and cam timing a little better

maybe stephen max and the other person who is getting adaptors made within the next few days could hop in here......maybe if that other person is running a similiar set-up I'd be willing to take my car to the dyno [even though it wouldn't be too accurate of a comparison] w/49* assuming it wouldn't be to much hassle for stephen max to set me up with that, I am leary though since it will retard the exhaust timing and I'm not clear on how/why that will effect the powerband (sorry to be asking for so much knowledge) and I def. can't afford to burn a valve either

KRRZ350

iTrader: (29)

holy crap! so many new posts while typing all that! <------edit, hahahaha, I missed a page

nismology

iTrader: (8)

It's quite simple. The 00VI uses dynamic supercharging (like the MEVI) while the 3.5 VI uses variable effective runner length but not in the traditional sense. They are NOT based on the same principles.
The premise of this thread is that the intake valve timing should be changed to alter the powerband. Whether or not you want to delve into the exhaust cam side of things is up to you, but i wouldn't recommend it since exhaust cam timing is not as straightforwad as the intake. I wasn't even the one that brought exhaust timing up. Anyway, I would actually think retarded the intake cam a bit past the 49* valve closing point will be beneficial. 49* is kinda mild IMO.

KRRZ350

iTrader: (29)

well in my case where I will be using adaptors I geuss I am stuck at 44* on the int. I'm still confused on the 3.5im though, I understand the principles of internal resonance supercharging I've been assuming your talking about that the whole time, maybe I'm on a different page though, when you say dynamic supercharging you do mean when the inertia from the incoming air hit's the back of the intake valve as it closes and then bounces back as the intake valve is opening again which happens at a certain rpm based on runner length?

nismology

iTrader: (8)

Couldn't you just order the adapters with custom specs? Or have you already received them?
Yes that's what i mean.

nismology

iTrader: (8)

I had a PM convo with stephen max a while ago about this. He told me they drilled it halfway between what would be full advance and full retard with operating VTC's.

KRRZ350

iTrader: (29)

I was out to lunch on that one, for some reason I was thinking that it would alter the exh. timing as well, duh. **** in that case toss me a number that you think would go good with a 75-shot and stock 5-mt vlsd gearing and I'll ask stephen max.

so out of curiosity/desire to learn, I have to ask yet one more question on the 3.5im, (you can pm the answer if you don't want to clutter this thread with stuff other than cam info)- what are the principles that the 3.5 variable effective runner length works on versus the traditional dynamic supercharging

JClaw

iTrader: (17)

With what SR20DEN posted in the VQ35HR thread it looks like my 70* intake valve closing guess was pretty good; my nismo cams have the same 10.5 mm lift as the VQ35HR and VQ35 Rev-up 7100 rpm motor, just more duration (262* instead of 248*):

Mad-MAX_SE

iTrader: (2)

Bumping this up, very good info in here.

NismoMaxman2

iTrader: (2)

anything new?

NismoMaxman2

iTrader: (2)

anything new?

kenji

iTrader: (1)

Your platform is desireable in this case, as you have the option of a SR20VE and all the goodies that come with it.

nismology

iTrader: (8)

Bump for new info in the first post...

95naSTA

iTrader: (10)

Since it wasn't mentioned, if anyone would like to know who was there to see the cams being drilled, it was abci30 and I.

TomV

iTrader: (6)

Thanks everyone for the thoroughness of this thread and good info to help out all us future 4.5 gens.

Can we sum it up for clarification? i.e. which method produces which timing. (we've already concluded that the 53 ABDC intake closing, produced by tilley's drilled cams, is "good"). That leaves stephen max's adapters (and that's all i know of as far as people who offer adapters or drilling service).

Was the 44 ABDC conclusion wrong (for the adapters)? I think that is what you're saying in the addendum to the 1st post but not sure.

oTranscendental

iTrader: (4)

Bump for the addendum.

nismology

iTrader: (8)

Tilley times the intake cams so the lobe seperation angle is the same as the 3.0 cams. This results in an intake valve closing @ 53° ABDC and 13° of overlap.

Stephen Max times them so that the intake valve closing event happens at the same time as the 3.0 cams. This results in an intake valve closing @ 49° ABDC and 17° of overlap.

KRRZ350

iTrader: (29)

I had stephenmax custom make my adaptors to 56* intake closing, it cost me a little more I believe ($125). All I have to go by is comparing it to a 4at 3.5, but damn this thing really pulls up top.

oTranscendental

iTrader: (4)

How dramatic do you think the difference is from 64* on the DE? and why do you think he did 53* instead of 64*

I'm trying to understand the point of the overlap difference as well... 13*>17* because it creates more pressure in the cylinder?

I'm going to go tune very soon and I want to be able to explain the differences between the stock vq35de and the way Tilley set my car up. Also the fact that the timing on the 3.0 ecu is different than the 3.5ecu.

I'm not familiar with the exact specs on the 3.0 cam timing or the 3.5 with Tilley's setup.

What are the most significant things to mention to the tuner so he can maximize the session?

Could someone do a comparison so the numbers are all lined up; like the HR cam data a few posts back. That would really consolidate the information between the swaps and the stock 3.5 motors.

Apparition

iTrader: (5)

Hey mike would 1jz cams fit?.. lolz

oTranscendental

iTrader: (4)

ok... all i really want to know is what the effect of not having 64* is on my power band, and where I'm losing most power.

nismology

iTrader: (8)

You're missing out on some low-end and top-end power. The VQ35 ECU retards the intake cams at low RPM to minimize overlap, advances it in the mid-range to improve dynamic compression by causing the intake valve to close earlier, then retards it up top to promote more complete cylinder filling.

oTranscendental

iTrader: (4)

Aside from adjustable cam gears, or working vtc, what can I do to get some of that power back?

I still have the 3.0 TB/ and MAF. I heard of someone using a Ford 3" MAF. If I replace these, I'm sure I'll get some more power but will it mess with my idle and smooth operation?


Sorry for all the newb questions, I'm just trying to maximize the setup before I go tune. For example I heard of some guy bolting the MAF directly to the IM by deleting the midpipe. Short of trying all the little mods myself does anyone know of a a setup that will keep good streetability and still wail in the High rpms? I'm contemplating the gutted IM, but we all know that kills your low-end