Ok so my car is still at Dynosty, she is a 04 VQDE 5AT... Fully built Engine is installed and done but when Hal went to tune her he could not get it to hold power. The first tuning session they had the 3.12 pulley installed and the graph looks more normal for a Vortech than these but no power, a bit of a dip near 4400rpms but then maxed out at 396hp / 325tq.

Dyno w/ 3.12 Pulley, disregard the aborted pull...



Then they installed the 2.87 to see if the slip came on earlier and this is what they saw... Check out the lines between 4250 and 5K, there is obviously something going on here and we thought it was the tranny slipping... HP was actually lower w/ 2.87 and the TQ still maxes out at 325 on the nose...



So thinking it's the trans slipping we shipped it to John at IPT and I had it go thru one of their built trans builds for $$$... Hoping this would solve the issue I was looking forward to smooth sailing once it got back...

So the trans came back in 2 weeks and they installed her and got her back on the dyno.... Well, this is what it looks like... Still have the same anomaly going on between about 4100 and 5K... Still peaking out at 325TQ..



I have searched many dyno charts and remember seeing something like this with that same sort of anomaly in the past somewhere but can't seem to find now to compare...

A bit of info... Hal assures me it's not belt slip as he can see if that was happening within the Haltech...

I have a NEW Edge Racing TQ converter installed for both pre-IPT and post-IPT attempted tuning sessions...

Boost is hitting 18psi and we all know where a VQ should be at those boost levels...

Fuel consumption is reading easily at 500+ WHP...


Any help would be GREATLY appreciated!

Thanks!

 

First, what does Hal think is going on?


The Dyno can measure Speed (MPH). Just compare the car and the Dyno….. If the Trans or converter is slipping they will be off.

Of corse you need to do this with the Converter in Lockup Mode.

 

He seems to think it's the trans still even after the IPT re-build...

The only thing that is consistent tho with those two graphs is the new TQ converter from edge racing... Hal says he has used them for other builds and has not had a 'bum' one before... John from IPT stands by his work and says 'drive it, you'll like it' but it can't really be driven until it's tuned...

But if the trans is slipping wouldn't you hear it 'revving out' where it is slipping?

Hal admittedly does not have a lot of experience with autos, thus is why I came here... To see if anyone else had a similar experience.

 

I'd think you would hear it……. but if you measure it, like i said above, then there is no question.

The Difference between an Auto and a Stick HP wise should not be that much.

 

Yeah... This is just frustrating...

$4k+ on a trans rebuild and it's doing the same thing pre and post build... And no codes tripped and no noticeable sounds as if it's 'revving out' at the points where it is showing the anomaly on the graph... Hal said it sounded smooth thru the pull but not getting to the wheels... Wheels and tires good, axle good, rear diff good, drive shaft good... When walking it back it brings him back to trans.... Or ... Tq converter...

 

I'm sure it's frustrating as Hell!!!!!!!

Aproching one year, way to long.

 

Yeah.... And A LOT invested to this point...

Just want a good running car... I am sure the work is top notch on the engine but this is just killn me... Being so close to the end and having this happen...

 

That's a Huge Investment………

 

doesn't that mean the torque converter isn't locking up?

 

Not sure... Hal and John at IPT both do not think it's the TQ converter... It is showing only a 2% loss at 6Krpms... Not sure on that. John said he would love to sell me another one if he thought that was the problem but he does not think that's the issue.

 

For those wondering here is the build list:


-Dynosty Stage 1 Long Block, includes CP Pistons, ARP Main Studs, ACL
bearings, Align Hone, Magnaflux and Micropolish Crank, Balance and Blueprint, Bore
and Hone with Torque Plate, Deck, Wash and Pro Assembly

-CP Pistons 9.5:1 Custom CR
-Manley Turbo Tuff Rods Upgrade
-Head Refresh Package, includes Valve Job, Mill, Adjust Valves, Clean and Pressure
Check. Includes new OEM valve seals.
-ARP L19 Head Studs
-Solid Motor Mounts
-Dynosty Pro Seal VQ35 Stopper Head Gasket Kit, 96mm
-Complete Engine Assembly (includes cleaning core components, assembly of timing
systems, oil pans)
-Nissan Oil Pump, 350Z Revup
-Dynosty Custom VQ Engine Build Gasket Kit, using Nissan parts, complete w/ new rear
main seal, intake and exhaust manifold gaskets, etc
-VQ35 Billet Main Girdle, with adaption for stock windage tray
-Nissan 350Z Rear Coolant Bypass Kit
-Nissan VQ35DE ATI Super Damper Balancer
-NGK Iridium Spark Plug, 1 step colder
-Injector Dynamics 725cc injectors
-ID 1000 Plug and Play Connectors for VQ35
-Walbro 400
-Rev Up Oil Pump
-Dynosty Stage 2 Fuel Return System
-Stillen Oil Cooler
-Stillen Tranny Cooler
-Treadstone TR1045 Intercooler

-Tomei VQ35DE Headers
-Motiv HF Cats
-Kelford Cams 266/260 Duration, 10.20mm/9.70mm Lift
-BC Single Spring & Ti Retainer Kit
-Cosworth VQ35 Twin Plenum Intake Manifold
-IPT Built Transmission
-Transgo VB upgrade
-Edge Racing TQ Converter
-929 Impeller / Blower Rebuild
-2.87 Pulley
-Haltech Tuning


So... I think that about covers the build list on this endeavor...

 

Do you have the A/F from the dyno runs?

 

Looks like misfire/blowout to me. Any data logs?

 

No.... No A/F charts but talked to Hal and he still has it very conservative on the rich side until he can get this anomaly figured out.

 

At this point I am not ruling anything out... Need to get a reading on the input turbine rev rpm speed -vs- the output rev rpm speed on the trans to either rule that in or out as a possibility... Then trouble shoot from there.

 

It should be possible to determine the slippage factor on the dyno and I see 2% was previously mentioned. If that is correct it would pretty much rule out the TC and trans as tire slip could account for that amount of loss. With the amount of work done on the engine it could be a caused by a lot of things so IMO the best approach may be to start with the most likely candidates. What appears to be occurring is RPM related and it could be one or more cylinders losing power starting about 4k and not recovering to redline. If the problem were mechanical it likely wouldn't start at a specific RPM. My first guess would be fuel or ignition related which is why an A/F plot would be helpful. If it were fuel it may be visible in the A/F but it would require a dyno pull with the 02 sensor in each of the tail pipes assuming they are two totally separated exhaust pipes.
Changing parts is an expensive way to trouble shoot so spending some time to try and pin it down could be worthwhile.

 

You are in good hands with Hal.

I really don't see the point of this thread. Its not like this forum is full with pro tuners. We only have Hal around.

Good luck.

 

One would think, if a nissan 5AT were dissipating 200hp of energy (140 kw) for more than a few seconds it would overheat or die very quickly. Check the trans temps during/after pulls to be sure if this is where you're really losing energy. I'd be surprised if the motor weren't the cause of this.

 

^ watching temps is always a good idea but Hal is pretty meticulous about those kind of things (assuming a gauge is present, of course).

My 5AT held a lot more power before showing slip on Hal's dyno. I also used an Edge Racing TC. I asked Andre to ensure it would hold 800 at the crank as I recall. The "anomoly" is the torque converter locking up, it brings rpms down and causes that dip or sometimes a loop on the dyno graph. If you do a run in 3rd gear it should be much smoother. At least that takes the lock up function out of the equation. If you've had the stator clutch fail in the TC, it will result in extreme inefficiency (as the stator can spin freely in either direction). If you have overheated the transmission in the past, all bets are off.

When problems occur, you often have to resort to ruling out items one by one. Given the new motor and new transmission (and similar dyno issues persist), I believe the most likely failure point is the TC. Talk to Andre at Edge, show him the dynos and see what he says. Did you tell him what power level it needed to hold? I have never heard a bad report of a built TC failing from Edge (assuming no overheat episode). If you asked Andre to build you an 800 hp capable converter (usually costs 400-500$), then I don't know what to say.

It's the transmission or TC... See what kind of customer service IPT will give you. Good luck man.

 

I thought in the past I saw a similar dyno result and could not find it in 'search'... I tried all different combination of words and it didn't come up. I was hoping maybe that person would see this thread and pipe in as to the cause of what his issue was.