I think the dyno starts measuring once you WOT it. No one wants to measure their car's output with only <40% throttle.

 

Those a/f ratio plots are the open-loop fuel maps. What i'm talking about is closed-loop.

Closed-loop = Less than 40% throttle, less than 3000 RPM...o2 sensor feedback is used to maintain a 14.7:1 a/f ratio. The ignition timing also uses a feedback system using MAF voltage, load/throttle position, engine speed and some other things to determine the timing advance

Open-loop = Equal to or greater than 40% throttle/3000 RPM...the ECU reverts to a/f and timing maps that are already stored based on MAF voltage and RPM to maintain stable combustion at higher loads and engine speeds.

 

You're exactly right. I just checked the FSM and codes P0172/0114 and P0175/0209 would show up if the amount of compensation was too large and if the actual ratio was much richer than the theoretical. Guess the ECU can compensate for these larger injectors with no problem. In that case, i'd suggest that anyone doing the swap with the 3.5 injectors run 53 PSI full-time. This ensures the best possible fuel atomization even at low throttle angles.

That SMT-7 business looks better and better to me everyday.

 

Just gotta get it working this winter...

They mainly did the closed loop tuning for cars that are boosted, but not boosted from the factory. It's main purpose is to richen up closed loop A/F when the car gets mild detonation in closed loop due to partial boost and the ECU trying to acheive a lean A/F. But I think it can work on a N/A application.

 

I have not seen this in the FAQ. Would one be able to retain cruise control after the swap?

 

Depends on which TB you end up using. The PF TB is the best route if you want to keep the cruise.

 

You can keep cruise control no matter what TB you use, as long as your TB has the CC throttle cable attachment.

 

Ya its going to take a little more work though with the drive by wire one. I am going to try and get an extension welded on the shaft to accomodate it. I can do without A/C and PS but not cruise.

 

hey y cant you use the vq35 timing chain covers with the 3.0 ecu?

 

You need both 3.0 inner and outer timing covers on the 3.5 block. There's a big hole in the middle of the 3.5 timing cover, wouldn't match with the 3.0.

 

The primary reason for having to use the 3.0 timing chain cover IF you're going to use a 3.0 ECU is so you can use the 3.0 cam position sensor. In turn, you also have to retain the 3.0 cam gears.

 

yeah i figures that much,but i no for a fact on the vq35 the cam sensors are on the opposite side of the engine and theres two of them.so y couldnt u jus one of those?or is the signal from that one different from the one on the vq30?and where is this big whole that sr-71 is talkin bout?

 

i just did the 3.5 the 3.5 doesnt have a coolant temp sensor like the 3.0 does
also i have the nismo fpr regulator how do i adjust it

 

It's very simple really. 3.0 ECU = 3.0 cam position sensor. Besides, the 3.5 cam position sensor gets its reading from marks on the intake cam itself. The 3.0 sensor gets its reading from the main intake cam sprocket. Either way, it wouldn't work.
I'm not quite sure what he's referring to.

 

That's why you use the 3.0 coolant tube so you can retain the 3.0 coolant temp sensor.


Turn the **** thing? Also, you're going to need a fuel pressure gauge installed in-line. I would suggest adjusting it for 53 PSI at WOT, then disconnecting and plugging the vacuum source so the fuel rail sees 53 PSI full-time like the 5.5 gens.

 

k thanks makes since now

 

You have to use the 3.0 coolant pipe.

 

which way do you turn it to adjust it
where can i find a guage i could use for this and leave it in the engine bay
im goin to install the 4th gen coolant temp wednesday and then wire up the summit rpm switch to the solenoid to the coil pack once i find out how to do it

 

sounds like its worth it for the cash

 

I would like to correct myself. I've been saying in this thread that the fuel pressure should be set to 53 PSI when the correct spec is 51 PSI according to the 2002 FSM. Just wanted to clear this up for everyone.

 

im gettin a code for cam/crank sensor p code 1336 and car buckin when it reaches 3500 rpm to like 5100 then it pulls hard to redling i thought it was getting to much fuel but i adjusted the nismo fpr

 

Are you using the 3.5 oil pan? If so, you have to shave about 1/4 inch off where the CPS at trans goes, If not the sensor is too far away to read the flywheel properly.

Are you using a UDP?

What did you adjust your fuel pressure to? It should be at 51PSI with the 5.5gen injectors. If you adjust it down, you'll get not only less fuel, but bad fuel atomization. Adjust it up and you'll be getting too much fuel in open loop.

 

yea im using the 3.5 oil pan ok ill try that and shave down like you said
im using a stock udp but im about to purchase an unorthodox udp for the 97 and put it on the 3.5

i have the fuel at 51 when i rev it up it goes down im about to try and put my stock 97 fpr and see how my car runs

i still dont know whats wrong with my car
when i rev over 3500 till 5100 5200 my cars like buckin but after that the car pulls strong

i checked the codes i still just have my 02 sensor and the cam/crank sensor p code 1336

 

D***n dialup, I cant get all the pics completed, and at work they have websense.

I am getting prepared to put a VQ35 in my SR20 powered car, but research is hindered with such large pages.
What I have found so far is that the weight will be close with no PS, aftermarket flywheel and the 5 spd gearbox.

Mike

 

im gonna try and put the stock 98 fpr on and then see how it runs

 

don't be a cheap @$$, get a real FPR. The 98 FPR will run the fuel pressure too low. You'll get poor atomization, less power, and worse gas mileage.

Imagine a water sprayer. Pull the trigger slowly and water drips out. Pull the trigger hard, and you'll get a mist. It's the same with fuel injection. If you use the 98 FPR, the fuel pressure won't be high enough and you won't create as fine a mist of gas.

Will it run? Yes, maybe without too many problems. JCLAW is running it with the 95 FPR, but I know his car would run better if he used a different FPR.

 

ok so then my fuel guage is either hooked up wrong and/ or wired wrong then
it idles its at 51 then when i rev it, it goes to 42 then alil lower
i was driving around town today and i got on it the fuel went to 62 duno

 

or maybe i should just find another fpr with a built in guage to it and it would be easier to adjust it to the 51psi

 

Well a FPR is supposed to be lower at idle and higher at WOT/zero vacuum. Something is installed incorrectly. Do you have a vacuum source attached to the FPR?

 

i have the nismo fpr in the fornt side of the fuel rail and on the back side just a plain fuel line i ordered the fuel damper for it and im gonna install it on tuesday and then adjust it again

 

is there anyway to have the cams on there secondary setting all the time or when u switch cam sprockets do we jus lose i completely

 

 

There isn't any "secondary" cam setting...................

 

second try. you have to use the 3.0 cam gears for the swap.and on the 3.5 cam gears it has the variable valve timing.on the 3.5 you have a normal lift on the cams and you have the performance lift on the cams.is there any way u can use the performance side on the cams.or is non ajustable since its on the 3.5 cams it self(the part were it switches over in the upper rpm range)?basicly like a permantly on variable valve timing?

 

Nope, not possible. When using the 3.0 sprockets, the lift is determined only by the shape of the lobes.

 

ok thanks very much

 

The lift doesn't ever change, even with operating VTCs. What changes is the intake cam timing, i.e. when the cams open the intake valves relative to crank angle. In the Maxima VQ35, the exhaust cam timing is fixed. So at low speeds the intake cam is retarded relative to TDC, and valve overlap (the amount of time that the intake and exhaust valves are open at the same time) is minimized. This results in smooth idling and it maximizes torque at low rpm. At high rpm the intake cams are advanced relative to TDC and valve overlap is increased, resulting in improved volumetric efficiency (engine breathing) and concomitant increased power.

 

Wow, great thread. Swapping a VQ35 into a B15 is an ongoing project going on right now... and a swap kit will be produced for other Sentra owners who are interested in doing this as well. Thanks for a great write-up. BTW, if you're curious: http://forums.thevboard.com/viewtopi...er=asc&start=0

 

TILLEY - YOUR INBOX IS FULL! So i'm posting your PM here for now so i don't lose it ... i'm too lazy to retype it:

Hey-

I was reading SR-71 Blackbird's thread on swapping VQ35s and he mentioned that you sell VQ35 motors ready to be swapped? I was wondering if these are tested to work and warrantied in anyway? Also are they pulled from wrecked vehicles? Preferably with low miles?

Thanks for any info ... i'm looking to find a good condition and decently priced VQ35 with 6-speed tranny (LSD if possible). Thanks.

-Dan.

 

just call him