You seem to have one of the more powerful Maxima's in here (6 more hp than MegaMax had with a chip). Can you post a pick of your dyno printout or is it a G-Tech number? If it is a dyno, I'm curious to see where you start making more power than my Max. I pretty much have the same mods as you except for the AFC and extrude honed intake. I dynoed 176hp and 193 torque with a scorching intake manifold. Thanks.

Dave

 

I just have a hardcopy of the dyno plot. Let me see if I can scan them...been meaning to do this for a long time...and I'll post it here.

FWIW, I don't think the dyno results mean that much. I kinda think my results are incorrectly high...everytime I've GTeched my car, it's done worse than my dyno indicated I should...so I'm not sure my car is at all faster, if not slower, than yours and Megamax, for example.

But I'll post the dyno when I have it scanned.

 

Last night, I talked to the owners of the speed shop where I got my car dynoed and they informed me that it is not wise compare someone elses dyno plots which was taken off a completely different dyno jet. They told me Dyno Jet is always improving accuracy within their systems which increases the differences between Dyno Jets constructed at different times. They said the best way to gauge your numbers and performance is on the same dyno everytime, otherwise your numbers could be flawed. They said different Dyno Jets can read as much 6% higher than another one. I shouldn't have been so stupid and dyno my car with a baking engine, but I was too excited at the time to care.

Your numbers might be right on for the particular Dyno Jet you used.

Dave

 

This is true but you can compare the shape of the torque curve in relation to yours. The thing with the VQ is that without the 5th gen intake manifolds or NOS/SC its hard to make more power. Basically you guys with bolt ons are maxing out what power can be made on your mild stock cams. Given a higher rev limiter, stiffer valve springs/retainers with a better cam (hopefully it won't trigger a MIL) you will make more power. From the dyno's I have seen of the VQ's the power falls sharply right after 5800rpm. Since Keven said the extrude honed intake manifold didn't make much of a difference, that means the intake manifold isn't really a restriction. The combination of long runners and mild cams are to blame. The only problem is that to get proper cams ground you need new billets. Since you have to have 4 camshafts it wouldn't cost much to get them reground. However it would take about 1-3 grinds to find the best results. Also I believe if someone had some new core billets and when to JWT they could grind a very good cam. As of right now JWT has the best overall street cams for the SR20DE and VG30E. Then one can get a custom program for the cams too .

 

Cams would be nice, but the money and effort isn't cost effective for me. In order to really make the new cams more effective, a new intake would have to be built, preferably one with shorter runners to improve topend performance. Plus, I don't trust regrinds.

I don't think my VQ is "tapped out" in performance just yet. I believe there is another 10-12 fwhp and torque in the ECU by adjusting fuel mapping. I believe there is a little power (5-8 fwhp) to be found by port matching and deburring the TB and intake manifolds. I'm not talking about extrude honing. Adding topend power doesn't really matter to me. I would much rather have a large and flat hp and torque band. I don't like driving topend hp cars because they are peaky and annoying to drive. Give me more torque and mid range power (I'm a musclecar guy by heart). My car stops making power after 5500rpms and that's no big deal to me. I think the VQ is capable of 200 fwhp and 210 ftlbs of torque with the right work. That much power in a 3000lb fwd car is more than enough power for me. I've run 14.9s@94mph in the heat and with poor traction without my rt cat or my lightweight 16s. If I can get into the low 14s, that is plenty for me and my 4-door. The bragging rights of already being in the 14s with a NA V6 sedan is good enough for me. If and when I ever feel brave, I'll do some port matching. Right now I'm debating between getting the UPRD ECU or just getting a Field's controller. I believe they both do about the same thing. The Field's would have to be dyno tuned though.

Dave

 

I suggest the ECU because it can change your timing curve where as with the fields you can only do the fuel curve. After all you can fine tune the UPRD ECU with the fields controller (like for race gas or those really cold good days). When I dynoed my CAI, I was able to adjust my A/F mixture and picked up 4hp/5lb-ft over my baseline run. Not to mention the timing change will increase the lowend-midrange torque probably the same as the fuel adjustments. Believe it or not when Biomax used a 95 JWT ECU he said he gained an average of 7hp/10lb-ft from 2000-5000rpm. Now that would give you the results your looking for, however finding traction will be a ***** .

 

Yep, Ignition timing is where much power lies. Too bad the Apexi ITC dosent work on the Maxima. Their has to be a simple way to modify the timing. The ITC is way complicated because it modifies the timing differently at various RPM's. I would settle for changing the base timing. +5degrees across the board would wake the Max up! Their has to be a way to play with the crank position sensor signals to the ECU or the input signal to the coils. DAM I need to get an EE degree LOL!

 

Nismo87SE:

Thanks. I might have to buy both then. Unfortunately that will cost some cash (~$700). The timing thing really hadn't occured to me yet. As for traction, tell me about it. 2.4 60 foots don't help your et at all. Rolling into the gas in 1st equals spin city. The spinning might go away a little after I get my Koni fronts put in on Saturday (the wife informed me they came in today )

Dave

 

I remember a while back everyone was saying the timing is not adjustable on the VQ30DE. I find this hard to believe, the thing is you have to get to the base timing mode first. In my Z32 FSM you had to make sure the engine was warmed up then unplug the TPS and race the engien 3-4 times. This should lock in base timing, then you adjust the CAS to advance/retard the timing. It would be nice to have that techtom mdm-100 too. Here is a link to what the techtom unit functions is http://www.twinturbo.net/ttnetfaq/FAQpages/mdm100.html. Its a pretty nifty device I would have gotten one but it doesn't work with my car .

 

Is that JohnY's Z32 FSM? Last time i talked to him he wanted me to tell you that he needs it back. He needs for home and one for the garage.

 

Cool, hell I might just have to buy it from him lol .

 

Trust me, it's not adjustable. The crank position sensor, which is the main sensor used to trigger ignition timing, fits into a hole in the timing chain cover. It fits snugly enough that there is no way to rotate it to get even another degree of advance. You *could* modify the sensor such that it's adjustable, but I haven't thought of an easy, non-destructive method of doing so yet...hmmm maybe I'll put some effort into that.

FYI, I've looked in the Nissan FSM. It states the timing check procedure, similar to what you've mentioned, but there is absolutely no mention of adjustment, not even implied.

 

In discussing what power mods are still yet unexplored on the 4th gens, I'm surprised that NONE of you have even mentioned the 5th gen intake manifold. That's responsible for ~85% of the gain from 4th to 5th gens. All the gain comes on past 5000 rpm, but that's really where the 4th gen need it.

I'm also confident that the dual-fuel regulator fuel rail setup on the 5th gens would give a little gain, if anything remove the spikeyness from the 4th gen torque curve...check out a 5th gen curve, much smoother than the 4th gen. I think the last couple of cylinders on the fuel rail setup on the 4th gen are getting starved on modified 4th gens. Just another option.

I see the potential of a normally aspirated 4th gen with all the available N/A bolt ons and the 5th gen intake manifold and fuel rails being in the 210 HP at the wheels mark...more or less 20 more than my car right now. That'd be in the neighborhood of 255 at the wheels (similar to a modified M3). All just speculation, but pretty reasonable.

 

In discussing what power mods are still yet unexplored on the 4th gens, I'm surprised that NONE of you have even mentioned the 5th gen intake manifold. That's responsible for ~85% of the gain from 4th to 5th gens. All the gain comes on past 5000 rpm, but that's really where the 4th gen need it.

I'm also confident that the dual-fuel regulator fuel rail setup on the 5th gens would give a little gain, if anything remove the spikeyness from the 4th gen torque curve...check out a 5th gen curve, much smoother than the 4th gen. I think the last couple of cylinders on the fuel rail setup on the 4th gen are getting starved on modified 4th gens. Just another option.

I see the potential of a normally aspirated 4th gen with all the available N/A bolt ons and the 5th gen intake manifold and fuel rails being in the 210 HP at the wheels mark...more or less 20 more than my car right now. That'd be in the neighborhood of 255 at the wheels (similar to a modified M3). All just speculation, but pretty reasonable.

Personally, I think cams are a waste of thought. They'd be horrendously expensive (including installation costs), and they would certainly not be optimized to the motor being one-offs, thus would result in mediocre (10 HPish) power gains and torque losses down low. The only thing I'd maybe consider would be trying to tighten the valve lashes a little to gain a couple degrees more valve timing.

 

Since you seem to have an EE type of backround how hard/expensive do you think it would be to build a crank position sensor siginal interception device that could delay of advance the signal?

I bet the delay would be easy, but the advance would require more of an effort.

I have a few EE friends I wil ask about this too.

 

I was told, second hand info here, that the heads on the 4 4th & 5th gen have a diferent shape intake ports and the 5th gen intake wont line upon the 4th gen? I havent personally looked at a 2k motor for more than a few seconds, so I really cant say. But perhaps in the neer future they will start to show up in some salvage yards!!!

 

Actually, I don't have an EE background, just some experience...I tend to oversimplify EE issues with my ME mind a lot...guess I BS my way through things!

But yeah, that's definitely I possibility I'd imagine. I still would like to look into modifying the crank pos sensor/recepticle to allow some advance. I'm sure there's a way to do it to give another couple of degrees, maybe up to 5. I'll look into it, and I certainly think you should look into your idea. There's gotta be something that'll give us what we want here.

 

Hmmmmmm

Intake air temp sensor.....I have read that this effects timing?

MAF is for fuel, (S-AFC?)right?

So could you modify the IAT signal to trick the motor into thinking the intake air temp is cooler? I dont know if this variable would effect the WOT MAP or not? I'm sure it would at PT.

But, if the AFC adjust the MAF signal to increase injector pulse width at WOT, then why wouldnt adjusting the IAT signal effect the timing?

DAM I would need a Techtom to see if it would work. Is their any other way to read timing that you know of?
You have a shop manual?
What is the test procedure for the IAT sensor?
What is the signal type and range?

 

Now that is a good idea. There is only one way to find out if it fits, goto the local dealer and compare the gaskets. I wanted to see if a VG30DE manifold would fit a VE30DE one trip to the dealer and that idea was scrachted. If I get up in time I'd check out the differences in the gaskets for the intake manifold and collectors on the 4th and 5th gens. Also note the manifolds would probably run like $300+ since the 5th gen VQ is in short supply. Then you need some way of controlling the switchover and there could be differences in sensors and there locations. The possiblitys, with this manifold swap and a fine tuned ECU with a higher rev limiter. Like Keven said there could be good gains, probably around 15fwhp+.

 

Easy, use one of the inexpensive ($35) "turbohawk" shift lights to drive a relay, to make the switch, if it is an electricaly controlled process.