7MGTE dyno runs, input appreciated

[boxh34d]

Hey there everyone.
Below are some dyno runs after I installed a dump pipe on my MA71, and I'm a bit puzzled by them.
Car is Aus MA71 manual, stock engine with 175,000kms, 2.75" divorced dump with waste pipe coming in around 18" down stream, 3" system with cat and 2 mufflers. Std air box and filter, with front cut out of box to get air in there, and standard piping and cooler.

Boost and power:



The boost ( top line ) comes on really early, but doesn't hold a set pressure. It just keeps climbing and then tapers off just before the end of the run. Could this be a problem with the controller ( hyperboost type ), or with the wastegate not flowing enough etc?? The turbo is stock spec, just rebuilt.
We played with the controller settings, and this was the best we could do. We tried to get it to hold the wastegate shut for longer initially, but then it would open too far and the boost would have 3 or 4 fluctuations, causing minor spikes in the power curve. This was the best compromise of boost early, and keeping a smooth delivery.

The power ( bottom line ) is nice and linear, and feels great to drive, but it does seem a fair bit lower than what others are getting. I know every dyno is different, but I have seen quite a few up around the 170 to 180RWKW, and this is only 147. What do people think??
Thanks for any input.

[HKS_TRD]

Hey dude

Would be good to see a power run with the boost controller either switched off or removed from your wastegate control. Its probably not relevant but with a hi flowed stock Turbo I would see boost creep up to 12 psi at redline.

What boost settings are you running? WHen I first had my car tuned the boost was spiking alot on the dyno but after playing around with the AVC-R or it learning things seemed to settle down. You will probably always get a bit of a spike when uppig boost on the standard turbo.

Is your wastegate actuator shimmed?

[boxh34d]

The boost controller is a hyperboost one. A manual bleed valve, with course and fine pressure adjustment, and a dial for playing with wastegate open time ( well pressure anyway ).
Without the controller on, it had a lot less boost down low, and came on slower, but still kept climbing. Not as high, but it did creep at high RPM. It was a few weeks back now, so some details are a bit sketchy, but we put the controller back on, as it was better. We even tried just a straight turbosmart copy bleed valve ( I'm guessing the $15 ebay type ), and it didn't improve things.

Any more adjustment for wastegate delay would result in big spikes, like up to 8psi, then back down to 4 or 5, and it would just get worse from there hitting fuel cut, so this is what we got.

The actuator is not shimmed. When the turbo came back from the rebuild, it had a pressure rating on the actuator face. IIRC it was 8.2PSI, but I could be wrong.

Any thoughts on the power??

[Kedderz]

for reference i made 180rwkw on spike 8psi with 3inch dump/3cat 2 1/2 cat back exhaust.
this is with no boost controller.

[jimmmayyy]

How long are the boost signal lines going to the boost controller??

The inherent restriction of the blled valve+lengthy lines can give such a reduced/or slower boost signal that the wastegate opens too slowly allowing the turbo to spike.

Does your gauge reference from the actual boost signal or manifold pressure?

[boxh34d]

How long are the boost signal lines going to the boost controller??

The inherent restriction of the blled valve+lengthy lines can give such a reduced/or slower boost signal that the wastegate opens too slowly allowing the turbo to spike.

Does your gauge reference from the actual boost signal or manifold pressure?

The lines are as short as possible, about 500mm. The feed is from the comp cover, and the dyno sensor we used manifold pressure.
I think your misunderstanding though. It's not the spiking thats the question, its the boost creep at high RPM.
Also, when I said about any more adjustment, it would result in fluctuations, meaning it dives by a few PSI, then spikes back up, continue for a couple more. The spikes were in the power curve, as a result of the boost diving and coming back up. I probably didn't explain that bit well enough.

[3BarSuperstar]

Does it have a standard turbo on it or hase it been hiflowed??

[jimmmayyy]

No not misunderstood, just trying to clarify something. A stock car should make what you're making.

If boost is constantly creeping up then the watsgate isn't doing its job. Are you able to see the computer advancing or retarding ignition? It seems like that when it spikes, the sharp sudden rise in pressure and charge temp is then causing the computer to shut it down, ie more fuel and retarded timing.

[boxh34d]

Does it have a standard turbo on it or hase it been hiflowed??

As above, turbo is rebuilt, standard spec.

Jimmmayyy: Sorry, I couldn't see where you were going with that, my mistake.

I might have to take the dump off again and see if the wastegate flap is fowling on the dump flange or something. That part of things was done by someone else, so I guess I should double check things.

Ignition maps etc, I don't have those things. How exactly does one check that?? Plug into TCCS when on dyno, or do it manually with a ignition diagnostic machine thingy ( test dwell time, and spark strength etc, and I assume timing?? ) Or hows it done.
As far as fuel goes, here is the power vs AFR, you can see its pig rich, but I haven't seen an 80's japanese turbo'd car that isn't. Hows it compare with what is typical??

HP vs AFR

[jimmmayyy]

Yeah good idea to check the wastegates operation. Easiest way to see where ignition is going is with a timing light.. you'll see the mark move backwards if timing is being retarded by the computer.

[thechuckster]

AFRs of under 11 when on boost is a way too rich.

[boxh34d]

Yeah good idea to check the wastegates operation. Easiest way to see where ignition is going is with a timing light.. you'll see the mark move backwards if timing is being retarded by the computer.

Ok, I thought you were looking for something graphed, or some actual readings, to compare, not just a simple, "yes, it retards on boost".


thechuckster:
Do you mean AFR's of under 11 are rich for a 7M, or they are just rich ( compared to the 12.5:1 ideal )???

[Esteban]

Rich for any petrol motor

[cambelt]

Its common for turbo toyota motors to get down to even low 10,s AFR,s , Its the factory way of adding some protection.
Dave