EDIT: Just to clarify this has nothing to do with me - I just posted it because it pertains to our motors.

Not sure if any of you guys saw this but they are starting to get some good numbers out of stock VQ35s.

http://www.my350z.com/forum/showthread.php?t=268465

563whp/557tq on a completely stock VQ35 on a dyno dynamics. DDs are low reading dynos too by the way, dynojet numbers would almost certainly have been over 600 wheel for comparison purposes. Tuned on a piggyback too (TurboXS UTEC).

 

OMG- Thsi is some rediculous amount of power. All i can say is that is insane!

 

That's psychotic. Talk about a grueling 2 month tuning session.

Still over 400whp (on DD) running 93 pump. I like the shape of the curve on 6 & 9 psi.

 

Didn't they say that they blew it up on the highway later on..?

 

yea something about the outside temps were much cooler than he calculated.

mis-tuning error on his behalf he stated.


still amazing after such abuse and on stock components.

 

most definatly amazin. Thanks neal for bringin this to our attention

 

Thats crazy.. good info

 

Amazing what tuning can do to a motor...

 

Good God, look how much the power jumps in just a 1000 RPM range...that thing must be neck snapping! He blew the motor though, supposedly because of the temperature drop between the street and the shop...It was on 18psi, so would that have happened at around 14psi? Forgive my ignorance when it comes to boost, but this really is amazing information!

 

Just came across that post today while looking around on supraforums, crazy numbers for a stock motor.

 

Yeah, pretty ridiculous on a tuned piggyback. So this guy doesn't have rods/bolts? That's next to ridiculous, stock fuel rail with 650cc's is delicious...

 

I didn't really grasp that outside temperature drop concept that well. I thought air is always better when colder. I'd can't stop reckoning that hotter air may hurt the motor more than colder air. Besides, boosted, air gets pressurized, thus becomes hotter anyways. If his tunes matter in such small range of temperatures, then that means we'd have to change fuel maps summer and winter? I just didnt' think that 85-60=30 degrees of temperature should be the constituent for that motor to blow up...

Anyways, those number are amazang!!!
On his highest boost dyno map, I basically see the motor being HP-driven, torque's mostly under the HP throughout except between 3k-4k rpms. Now that's our VQ-baby!
One weird thing, though, on lowered boost out of 93 octanes, torque remained flat throughout the mid-range, that was the first time I've seen such weird occurence on a dyno-map. Alright, I'm not doggin anything down, tho. This is definitely some amazing info to know. Thanks Neal.

-Peter-

 

Interesting.... those guys are local to me and I was thinking about going there for a dyno. Guess I can have some peace of mind that they do know a thing or two about VQs...

 

While the numbers are amazing.. I wouldn't say that those are "reliable" numbers, by ANY means.. The engine blew up when they put it through the ringer on the highway.. There's a difference between making a 8 second pull on the dyno, and making a full blast through the gears on the highway. The VQ35 rods won't handle that kind of abuse. People bend them with "good tunes" at the 500whp mark, in "real world" conditions.

 

Atmospheric pressure is what is irrelevant to a boosted motor, as its turbo/ supercharger creates its own pressure to feed the motor.

Air temp affects it, in this case, by having gotten colder over night. Keep in mind 18psi is alot of air moving through, and remember he mentioned being able to tune high 12s low 13s a/f. Thats pretty lean off the bat but he was able to pull it off at the dyno. The problem is when he went outside later and air temp dropped 30*. Air became denser- there was more oxygen in the same amount of air being fed into the engine, and there wasnt more fuel to compensate for it.

At partial throttle or cruising, the o2 sensors would see this and ECU would compensate with no problem. However, at WOT in closed loop, the already lean (relative for boost) a/f tuning was fixed, and could not compensate for the extra oxygen. Thus, at 18psi, the engine simply did not like the now even leaner mixture and went kaboom.

Werd?

Edit- I second what Travis is saying. Dynos really dont put as much of abuse into a motor as real world driving would

 

When it's tuned on the ragged edge like that, small atmospheric changes become more and more critical. Colder air is always better for "power" but more power is not always better - eventually you're making too much power and something's gonna snap which is what happened here. BTW fuel maps DO change for summer and winter - that's what a MAF does - it measures air density not just air pressure. That's one of the problems with tuning based on boost pressure alone - it doesn't take these changes into account so you have to give yourself a safety margin. Anyone who's datalogged on here and tunes via MAP will tell you that their AFRs will change, without any changes to their tune, from hot to cold weather. That's where your margin of safety becomes critical, but when you are tuned on the edge like this guy was, there is no margin of safety and things break.

As far as the torque goes, torque is always higher than horsepower until 5252rpm. The definition of horsepower is HP = (TQxRPM)/5252. If you analyze that equation for a minute you will realize that TQ will always be higher than HP below 5252 and HP will always be higher above 5252. The reason the torque curve was flatter on the lower boost dynos was because the boost was consistent throughout the run, whereas on the higher boost dynos it spiked up in the midrange and then tapered off up top, resulting in less torque.


I wasn't suggesting that this was reliable or advisable for anyone to attempt on a daily driver - I just posted it because someone pushed the envelope again. Previously the highest (posted) stock dyno was 518whp and was probably around 550whp (two pounds more boost than the 518 dyno) for an entire day of road racing before it finally let go when the guy decided to start revving it out higher which was dumb as far as longevity when living on the edge is concerned.

 

There's a intake air temp sensor in the MAF sensor to compensate for changes in air temp.. providing more or less enrichment depending on what the temp change is.. (up/down). I don't buy the whole temp change thing.. except for maybe the car was making 10-15 more whp with a 30 degree drop in air temp.. At any rate.. anywhere south of 500whp with a good tune should be fine for a stock VQ35.

 

Just confirmation of what i already knew. Those "crappy" rods can hold some power.

 

Good thread and some great numbers. But it does not suprise me thatmuch that a stock VQ35 tuned properly, with the right set up, on c16 can put down 560+ whp for a period of time. A great acomplishment none the less

 

The air temp sensor is never used for direct a/f control; the "hot wire" element can handle temp changes on its own. Secondly, we don't know if they clamped the MAF sensor and were using MAP as the load variable. But even if they didn't, there still needs to be some type of temperature compensation even with a MAF because the ECU won't necessarily enrich the mixture enough.

 

True.. I didn't think about it, but, changes in air density (colder/hotter) can be detected by the element in the MAF. I guess the air temp sensor is just used for closed loop changes?

 

thats an awesome number...now if someone.....cough ^^^^cough...would make me a turtle kit. lol.

 

Better quit smoking all that ganj.. coughing like that and all..

Let me see how Tardy the Turtle's car comes out first, before I take on any more B15 VQ turbo jobs.

 

yeah yeah, the one and only sounds good to me.

 

the fact that it was done is good to see but i would have been more impressed if they put the car more on the street after then did a couple of dyno tunes.

on another note like a yr ago someone managed something like 450+ on a stock 1.8t with a piggyback and that car also blew on the dyno after a day of tuning and multiple dyno pulls....i guess what i am saying is that the numbers they made are nice to see, but that only matters to those who can manage to run a car tunned that close to the edge. it would have been nicer( imho) if they were able to make big power on a setup that can be run on the street without the fear of blowing it. that might be alot more helpful to the vq community

 

Anyone can turn up the boost and make numbers........
I am not surprised it blew up....

Come on guys...... a few degrees difference in temp and the engine blew up. Are you all seriously buying that crap?

This is NOT proof that the vq35 can hold 550WHP on stock internals. In fact this is proof that it CANNOT.

 

Somebody give this guy a trophy.

 

thermodynamics will teach you that a few degrees change in temp can mean a huge difference in the amount of something you can fit into a given area....when you tune on the edge sometimes you have to fall off before u can turn that edge into a platform for others to stand upon.

lucky for us vq's are dirt cheap compared to some motors out there

 

Yeah it was already tuned lean (12-13:1) and using a map I believe (no adjustments) so obvious 30-40 F makes a big difference in the volume of the air.

 

What kind of damage did the engine suffer?