Eric92SE

All I can say is wow - what have I been missing this past year and a half. I forgot how quick this car is. I know some guy was flamed for saying they're worth 20 hp, but I know now that it definitely has to be more than the claimed 1-2. The difference is just amazing at low speeds. It feels like a different engine completely - much stronger and smoother. Before, you had to rev the engine beyond 3,000 rpm's before it began to pick up in power, now it feels more like my old VG with it's low end.

It cost me $1500 bucks to install the new ones, but I'm glad I did. My car has a totally different attitude now, I just wish I had had access to a dyno before and after I did this job.

Lordrandall

iTrader: (4)

VE Power!

Jason92SE

Did you do the job yourself? What parts did you replace and the prices of each part?

Thanks
Jason

Eric92SE

No, this is the one job on the Maxima that I wouldn't attempt myself. The parts themselves were about 1000 dollars (VTC's were $488 each and the required kit was $50 I think). The remaining $500 was in labor.

MaDMaX024

was it really worth the $1500?
hows the highway power? (i.e a 3rd gear downshift from 60-70 from 5th..) after suspension and coils and stereo (should be done by may...i hope) with graduation money i'm looking to have my engine and tranny rebuilt...154k now...

Eric92SE

Well I'd say it was defintely worth it - I downshifted going about 65 on the ride home and was in triple digits in no time. I've been thinking these past few weeks about which mods to get for power, and I didn't even realize how much weaker my car was with the malfunctioning VTC's. It pulls so much harder from a stop now that I can't believe it's the same car that dropped off two days ago to be fixed. I'll be going driving tonight and will be able to open it up on a few back roads, so I'll let you know how it goes later on this evening.

Bman

Great stuff! So the VTCs really ARE for the low-end range.

Eric92SE

Well I've been thinking about it. The purpose of the VTC's is to ADVANCE the timing 8-9 degrees, which is advantageous at high engine speeds. However, once they fail, I think that the timing is constantly 8-9 degrees higher. This would therefore make the car inefficient during the lower RPM ranges. I guess that the VTC's don't really add or subtract horsepower, but I'm almost positive that they have to dramatically alter your torque/power curve thoughout the rev-band. I would love to see side-by-side dyno sheets of before and after if anyone else is planning on having theirs replaced in the near future.

JonnyMax

I am picking up a VE engine with a spun bearing for 150 bucks in a couple days.

Best part is it has almost BRAND NEW VTCs on it. They will be swapped over along with all the othe rparts after I get them back for the machine shop.

JonnyMax

And I do plan on doin a baseline Dyno run soon too.

Eric92SE

That's excellent - I'll be awaiting your results.

Czar

Hey Jonnymax... Tell them how the VE spun its bearings!! (All VE engines that I have been in contact with were factory ringers, IMO)

JonnyMax

wasnt that on your little 150mph run on the highway?

Eric92SE

Although I haven't driven it enough to be sure, it appears as if my rough idle problem has been solved. Before, my car would sometimes drop revs while not in gear, sometimes so low that it would stall. This would happen even when rolling at 65+ mph - it's scary when you're coasting towards an off-ramp and you realize you have no power steering because the car cut off. If left sitting, the idle would typically oscillate between 650 and 250 rpms. I didn't think that the VTC's were the culprit, but after driving for about 2 hours on the new ones, the problem appears to be gone. Of course I'll have to wait a few days before I can confirm this, but it appears as if I've taken out two problems with this fix.

Bman

I don't know about that Eric... According to my FSM they advance intake valve timing when ON and this increases the low-end torque on this tiny power/rpm picture they have. This makes sense (to me) because I had understood that cars with old timing belts sometimes slip a tooth, causing the timing to be retarded and making the car feel sluggish.

Can someone back me up or tell me I'm talking out of my behind?

Eric92SE

Hmm that makes sense to me... I'm not exactly sure about this either, I'm just trying to connect what I'm feeling to what is actually happening with the car. Your sugggestion sounds like it could be right - does anyone know this for sure?

Matt93SE

iTrader: (44)

something like that...
at low RPM, the VTCs are "active"...

so when you disable the VTCs, you lose low end power, not high end as most people think the VTCs help.
if you removed the VTCs (which you can't), you would have a lot less low end, but the top end would still scream all the way to redline.

(and for those of you who don't think a VE doesn't go to redline, check out these dynos.. VE vs. VQ. )

VE
http://www.ee.utulsa.edu/~mblehm/pic...eline_dyno.jpg

VQ
http://www.freechess.org/~oxymoron/graph.jpg

Keep in mind that's a VE 5 spd against a VQ auto, but still.
pretty amazing, considering how much people tout the VQ over the VE.

Eric92SE

So Matt, do you think that that timing is what was causing my rough idle/stalling problem?

Jeff92se

iTrader: (82)

I've read the FSM a few times and it's confusing. It's almost like the VTC's are ON "advanced" on how rpms and then turn OFF at about 3000 rpms to allow the cams to "retard". So if no oil gets to them when they are ON, they clatter. Would seem to explain it I guess

Eric92SE

All this seems to confirm exactly what I'm feeling. If your VTC's are not operating, grounded out or not, you have to be losing at least 10 fwtq - I mean, the difference is immediately noticable. It feels like I added 2 cylinders to me car rather than two new cam sprockets.

JonnyMax

I wonder... I am gonna be going to the Dyno next weekend. What I was thinking of doing was to d oone or two pulls with the VTCs grounded like I have them now, and then one or two with them active (and clattering away). I wonder what difference this will show?

Matt93SE

iTrader: (44)

the difference will show. I was going to do that myself when I was at the dyno shop, but I forgot about it.. we got to playing with the power valve... FYI, leave it alone. if you turn it on early or late, you lose 10 or more HP.. nissan got the power valve dead on.

Bman

Wow thanks for those dyno graphs Matt. Never knew we had such a flat torque curve - I was pleasantly surprised!

No wonder it only takes about 2000-2500 RPM to tackle all those hills!

VE POWER!

CandiMan

iTrader: (1)

Now all you have to do to protect your $1500 investment is use the proper oil filter. For $500 labor it looks as if your mechanic just swap out the VTC sprocets, instead of pulling the heads and changing some blind plugs within the heads which relates to improving oil supply to the VTC's according to TSB #NTB93-189. I look forward to tearing mine apart and changing all related parts. I would like to do a before and after dyno pull but that's money that could be spent on parts. The FSM will be my new best friend during this procedure

Eric92SE

I've been using the Nissan white filter since I've owned the car

RosenKen

Any part numbers on those blind plugs? I ordered new VTC's and will be swapping them out myself, I'll be doing the rear head in 2 weeks. Do you have copies of the TSB that you can scan?

Jeff92se

iTrader: (82)

They are the oil passage squirter or something. I know there is one for the chain tensioner and maybe one right under the #1 cam tower caps. That one feeds the vtcs and the cam journal. I didn't replace them but ghetto cleaned them by using a really small wire. I guess it worked. :knocks on wood:

CandiMan

iTrader: (1)

I have all you need, TSB's, part #'s, etc. I got the TSB's from another member and will be more than happy to past them on you you. Besides the VTC and all needed gaskets, the TSB calles for

Tensioner oil jet, part #11036-96E00 (1 per head)
VTC oil jets, part #11036-F6510 (1 per head)
6 mm blind plugs, part #00933-20670 (1 for right and 3 for left head)

If you pm/email me a mailing address I'll send you a copy of these TSB's. Good luck with the R&R, nothing like a fuel injection engine firing up on the first crank after pulling the heads.

jrodder

Hey Eric..the performance problems you were having before you got your VTC's replaced sounds like my car right now- low RPM power is very lacking, have to downshift to get any kind of power, acceleration isn't very smooth. Tell me, was your car making any kind of noises that clued you in? My 92 SE runs pretty smooth, but its begun to make a slight ticking sound at idle, especially when cold..I've also noticed that it has greater power when the enginenis driven cold. Sound familiar at all?

Eric92SE

That sounds exactly like whatI was experiencing. Two weeks ago, I had the opportunity to drive 2 VE 5-speeds side by side - mine with malfunctioning VTC's, and my friends with operating ones. The difference in smoothness was immediately apparent. The VTC's caused my engine to run very rough, and I could feel it even in the accelerator pedal. The one with good VTC's, however, felt buttery smooth in comparison, and much stronger with a much more linear power progression. Now that I have new ones, I've been driving in the cold with no problems. Power remains even when the engine warms up. The difference in sound is just amazing. Right now, I really couldn't be happier with my Max. Well, then again, next week I'll have a rebuild tranny with an ACT clutch, so I still have more to look foward to.