Dyno Run Problems :( HELP

[spitalul2bad]

Hi guys...

Well, here's the story. I went to a local dyno today to see how it's going. It's spring, the sun was out, and I thought it should be okay.

I have a VQ35DE REV-UP engine. Current mods INSTALLED: HKS True Dual Ti Exhaust, Injen Intake, Motordyne MREV2 Manifold, Motordyne Plenum Spacer (5/16 I think), Lightweight Flywheel and a reflash for my ECU.

However... the dyno results were HUGELY disappointing.

After reading up on some forums, it seems the NORMAL VQ35DE runs STOCK 235 rwhp. However, with my mods and the REV-UP engine, I only got 201 rwhp!!!! WTF?

The engine has 4000 km on it... sooo... what could it be? I suspect it's the ECU reflash, but I really need more opinions... What the hell is going on?

Thanks.

[dasoupdude]

wtf

That dyno probably needs a reflash, try taking it to a different one and see if you get a similar number.

[spitalul2bad]

That was my first instinct... crappy dyno, and so on... However, I did the dyno with my friends (got a group rate), and their runs were right on the money. They got the stock factory numbers.

[dasoupdude]

You're on your second motor right?

[spitalul2bad]

Yup. Had it replaced under warranty at 17.700 km.

[spitalul2bad]

Noone? No ideas?

Here's what I've gathered from my friends and some Nissan dealer mechanics...

Issue: Very low HP number on dyno.

Possible reasons (or combinations of them):

1. Bad gas (petrol). Could be a bad batch.

2. Bad dyno. Try another one. (Although my friends used it and got normal hp numbers)

3. Bad ECU reflash. (Possible, but such a BIG loss of power?)

4. Conspiracy: When I got my engine replaced, the Nissan dealer DOWN-TUNED it so as to not let me kill another one under warranty (although, I don't think it was my fault). Nissan mechanics said this IS done sometimes and it COULD be possible, although they aren't TOLD about it... only management knows exactly. (And they're not telling me - yes, I asked.)

5. My engine got replaced with ANOTHER type of VQ35 (doubtful, but still).

So? Any other ideas? Fixes? Anything?

[dasoupdude]

Noone? No ideas?

3. Bad ECU reflash. (Possible, but such a BIG loss of power?)

4. Conspiracy: When I got my engine replaced, the Nissan dealer DOWN-TUNED it so as to not let me kill another one under warranty (although, I don't think it was my fault). Nissan mechanics said this IS done sometimes and it COULD be possible, although they aren't TOLD about it... only management knows exactly. (And they're not telling me - yes, I asked.)

Those make sense, but you're guess is as good as mine

[westpak]

those numbers do seem low but to get a perspective, what type of dyno was it?

also what was your air fuel ratio? do you have a picture of the dyno run you can post up?

What type of ECU reflash did you use?

[spitalul2bad]

I have a short video from the runs (I did 3):http://www.youtube.com/watch?v=Ly2x1-q3imw

I have no idea about the type of dyno... It's german.

I got the "performance plus" ECU reflash from Quantum Auto Sport (also german):http://www.quantumautosport.co...a1d25

Here's the description of the reflash:

Our ECU-Reflash 'Performance Plus' provides you with the following changes by reprogramming the engine control unit:

a. Annulment of Vmax limitation (series: 250 km / h) b. optional raising the rev limiter (if desired) c. optional raising the idle speed (if desired) d. Modification of the electronic throttle control for direct response e. Change the Target A / F (long-term performance of the lambda correction exhaust systems, intake manifold, offset etc) f. Adapting Zündüngs and Einspritzkennfelder on existing and additional modifications to optimize performance

QAS german shop caters to the 350Z, 370Z, Subaru Impreza WRX STi and Mistubishi Evos and sometimes Mazda RX-8s... and that's it. They sold me some of my parts (Injen Intake, HKS exhaust...) and seem okay. However, I did not contact them yet with my problem.

[westpak]

I have a short video from the runs (I did 3):http://www.youtube.com/watch?v=Ly2x1-q3imw

I have no idea about the type of dyno... It's german.

I got the "performance plus" ECU reflash from Quantum Auto Sport (also german):http://www.quantumautosport.co...a1d25

Here's the description of the reflash:

Our ECU-Reflash 'Performance Plus' provides you with the following changes by reprogramming the engine control unit:

a. Annulment of Vmax limitation (series: 250 km / h) b. optional raising the rev limiter (if desired) c. optional raising the idle speed (if desired) d. Modification of the electronic throttle control for direct response e. Change the Target A / F (long-term performance of the lambda correction exhaust systems, intake manifold, offset etc) f. Adapting Zündüngs and Einspritzkennfelder on existing and additional modifications to optimize performance

QAS german shop caters to the 350Z, 370Z, Subaru Impreza WRX STi and Mistubishi Evos and sometimes Mazda RX-8s... and that's it. They sold me some of my parts (Injen Intake, HKS exhaust...) and seem okay. However, I did not contact them yet with my problem.

well the type of dyno will make a difference in the numbers as load based dynos will read lower while some will read high.

If this is a mail in flash I am not a fan of flashes unless they have the air fuel ratios before hand to know if you are running lean or rich before, the flash will be a guess at best and you will end up having to send the ECU back and forth a couple of times to get it right. Best way is to tune the car while on the dyno.

To really see what the flash has done is to see the air fuel ratio curve from the dyno run, without it we can't even guess as to what the causes of your low numbers are, so do you have the dyno print out from this run? Without it the company that did the flash wont be able to make adjustments either.

Also did you have a baseline dyno from before mods or at least before the flash? Your numbers may have been low before the mods.

[spitalul2bad]

I sent the ECU with the mail thing because there's noone around me that could do a dyno tune.

I did not do a dyno before the reflash.

I outlined my mods and sent the ECU to be flashed. And that was that. No back and forth, no anything.

I will scan the dyno print-out tomorrow and post it. But I don't have a "before" one so... that's a problem there as well.

The dyno is pretty accurate... I think. My friends and I all got a group rate, and their numbers were right on the money. (manufacturer stated hp). +/- 5 hp.

I thought about the mods reducing power but... THIS MUCH power?! Don't know...

[westpak]

I sent the ECU with the mail thing because there's noone around me that could do a dyno tune.

I did not do a dyno before the reflash.

I outlined my mods and sent the ECU to be flashed. And that was that. No back and forth, no anything.

I will scan the dyno print-out tomorrow and post it. But I don't have a "before" one so... that's a problem there as well.

The dyno is pretty accurate... I think. My friends and I all got a group rate, and their numbers were right on the money. (manufacturer stated hp). +/- 5 hp.

I thought about the mods reducing power but... THIS MUCH power?! Don't know...

yeah mail in flashes are tough specially with an NA car trying to fine tune a few horses, it is much more forgiving with boosted cars where you can be conservative and still make more power.

Not having a starting point dyno makes it tough to know whether the tune and mods lost you power or your engine started with less power to begin with.

To be able to get the tune better through the mail, the tuner will need the air fuel ratio to know whether he needs to add or remove fuel. I would also get something like Cipher from Uprev to data log your timing so you know what it is and if it is conservative or too aggressive.

Too conservative and you loose power and if too aggressive and you may have knock and the ECU pull timing and loose power.

[dasoupdude]

Maybe if he can get a hold of the Cipher software Jack could try and tune his car from the US, as he did to that one GTR that was overseas..

[westpak]

Maybe if he can get a hold of the Cipher software Jack could try and tune his car from the US, as he did to that one GTR that was overseas..

He could but it would mean more investment at this point, since he already spent the money on the flash I would figure out if they did what he paid for.

[spitalul2bad]

Actually, I wouldn't mind spending a bit more and having at least the manufacturer stated horsepower. I'm really low on power right now and I just want to identify the problem and get it fixed, even if it means paying for it.

If we're settled that it's the A/F timing in the ECU, point me to the right place and I'll be happy to see it fixed.

[westpak]

well lets start with the dyno chart, post it up and we can see

[bmike818]

[spitalul2bad]

I finally managed to scan the dyno print-out I got.

[SoCalSideways]

when was the last time you replaced your clutch?

[spitalul2bad]

Never.The car has 22.000 km or 13.670 miles. It doesn't slip or anything else peculiar. Why'd you ask?

[westpak]

well the chart doesn't show your air fuel ratio, but I see that the readings are in KW which when converted to hp you get around 270 and that looks to be a load based dyno so the 270 is around what you would expect with the mods you listed, so I would say you are fine
Modified by westpak at 8:41 PM 3/24/2010

[spitalul2bad]

270 hp at the crank is okay?Are you sure?

Then I'll stop worrying about this... although I did say that the dyno might suck as one of the possibilities for this... But I quickly rejected this because my friends' dyno chart was right on the money... they got the claimed manufacturer crank hp. That's why I ruled it out.

[westpak]

270 hp at the crank is okay?Are you sure?

Then I'll stop worrying about this... although I did say that the dyno might suck as one of the possibilities for this... But I quickly rejected this because my friends' dyno chart was right on the money... they got the claimed manufacturer crank hp. That's why I ruled it out.

OK I apologize, reading that chart is a little odd, not like others with the different powers and different units of power.

But upon reading it again I think the dyno numbers are a little funky, the way I think it reads is:

276 Engine HP201 RWHP

These would be low for the mods you have as the engine HP should have been around 330 or so.

That being said the loss between Engine HP and RWHP of 75 HP is way too high, it should have been around 40 at the most.

Also the drag HP is a factor, if that is similar to "parasitic" losses on a Mustang dyno then unless they did it specifically for your car it might be off.

Then if that dyno is a load based dyno as I think it is like the Mustang there is about a 12% difference from a dynojet which is what most people get their reading on so your numbers would be closer to:Engine HP 310RWHP 225

so if I am reading the chart correctly now that is still way too much hp loss from engine to wheels, I would get an explanation from the dyno operator as to the 75 drag hp

sorry for confusion but there aren't many of those dyno's here in the US

[spitalul2bad]

It's okay. No need to apologize. I wan't snappy or anything. I just want to get to figure out if there's anything wrong or not.

Yes, it's 276 engine HP and 201 RWHP.

I also expected somewhere about 315-330 hp at the engine and 245-260 RWHP. That's why, when I saw these dyno numbers, I started this thread.

The operator did NOT adjust the HP drag. They seem to be using the same one on all runs. I don't know what it is. I will drop by the dyno and ask the operator as to what it is next week.

Finally, I would guess that such dynos are not common in the US. Heck, they might not be common in Europe either. It's just the closest one to where I live... other ones are 300 - 400 miles away...

[westpak]

It's okay. No need to apologize. I wan't snappy or anything. I just want to get to figure out if there's anything wrong or not.

Yes, it's 276 engine HP and 201 RWHP.

I also expected somewhere about 315-330 hp at the engine and 245-260 RWHP. That's why, when I saw these dyno numbers, I started this thread.

The operator did NOT adjust the HP drag. They seem to be using the same one on all runs. I don't know what it is. I will drop by the dyno and ask the operator as to what it is next week.

Finally, I would guess that such dynos are not common in the US. Heck, they might not be common in Europe either. It's just the closest one to where I live... other ones are 300 - 400 miles away...

Yeah I think you have a couple of things going here that you need to clarify with the shop

Is it a load based dyno?If so as I mentioned they read a bit lower so your numbers would be about 12% more to compare to dynojet numbers.

And find out what the drag hp is, if it is used to add to the rwhp to get the engine hp then it is way too high and they are inflating their dyno numbers, if it substracts from their calculated engine hp to get rwhp then it is way too much lowering the rwhp too much

[BusyBadger]

It seems like West has addressed a lot of your issues, but something has been troubling me...

What's up with the power drop after 6000 rpm? Every graph I've seen from a RevUp has the engine pulling all the way to the 6600 mark.

[dasoupdude]

Gus, I Think its time someone needs another overseas tuning session with Jack..

[westpak]

lol well he liked the trip to the Dominican Republic for the GT-R's