Went to the mustang dyno sunday and put the 401 twin turbo on there just to see what it would do. Did 3 pulls.

Set it to 14psi but leaned out the mixture abit more than my last track outing which went 9.86 at 141.

On the dyno, even tho its a loaded mustang dyno, the car only saw 12.5 psi at peak rpms. It was near 12.8 but faded to 12.5 and ran 1/2 point richer than normal on the street. So it wasnt loading it as much apparently. Normally run about 11.8 to 1 or so on street, it ran about 11.2 to 1 on dyno pull.

Car put down 638whp I believe corrected. No idea of the torque, as on the throttle hit and as boost came on, the dyno showed over 1000wtq and came down steadly as speed went up.

So i turned the controller 1 turn to hopefully get back to 14psi and it spiked to 18.5 psi and ran very rich, into the 9's air fuel. Put down 674whp corrected and 1070ish wtq but again thats probly converter flashing multiplying the torque or something.

So the car handled a BUNCH of boost on pump gas 93 with little to no problems. I decided to turn controller down half turn to hopefully get it near 15 psi or so. I turned VE down alittle on my chip and let it eat.

Last pass actually made 17.5psi at peak and with air fuel about 10.0 to 1, it made 690whp corrected and 1086wtq torque spike peak. So with 1 psi less and slightly better air fuel it picked up 16whp so not bad, just shows TONS more in the tune. On the street it would lean out a good 1/2 point or so.




Some thoughts/conclusions/possible problems....

It appears the converter may be too large and/or i have a back pressure issue. Peak hp appeared to hit at 5200-5300 rpm but the cam is suppose to peak closer to 5800 rpm.

Due to the converter the dyno rpms dont match true engine rpm. On the hit, the converter just goes to 5300-5500 rpm and stays there the whole pull until about 130-135mph and it moves abit to 5700ish. I am not sure if its suppose to do that or not but its beyond my peak hp rpm so thats not good.

I am leaking oil out the valve cover fittings and at the turbo drains and i think out my rear block fitting for the turbo oil supply. I think its getting too much backpressure and oil is seeping out where it can since it cant drain into the pan fast enough nor can the crankcase be evacuated well enough with my vent system. I have a .68 a/r and I think i need .96 a/r and possibly a bigger compressor. Seriously thinking of trying larger housing and or 64mm turbos. Backpressure may explain why the cam peaks earlier than it should.

I'm not picking up much per psi boost, even tho the tune was abit off for the higher boost pulls. If it picks up 100whp with tune, that would mean 30whp per psi which is very good but not sure i have that much power left in the car at that pressure level. Most setups i hear pick up 20-30whp per 1 psi boost unless you have backpressure problems.

I know the dyno numbers dont really mean much considering the converter and rich tune, its not going to show true power. I really dont care too much because the car runs 9's at 140mph+ so the setup is working. But i'm curious if I have alot to gain with same boost pressure with larger housings/turbos to limit back pressure if its true that I have a backpressure problem. If thats the case I'm upgrading turbos for sure. may do it anyway just because I want to go even faster May go for 8.99 in the next year or two.


VIDEO

Ignore the rpm readout as its not correct. Not even sure the mph readout is correct either so not sure how accurate these numbers even are

http://www.youtube.com/watch?v=uArThEOcm_M

 

Very good. I agree that you have a lot more in it by the time you get everything dialed in. When all is said and done you might have an 8.99 second car.

 

step it upto Twin Turbonetics T76/Q-trim/.96A/R will be more turbo then you should need.
Even Twin 72mm turbos will get ya to the 750+ RWHP mark.

 

I think these turbos with better tune will do 750whp on this dyno, i'm only 60 away

64's will get me in the 800's i bet which is 200 more than my 9.8's passes that have no launch. thinking of transbrake and rear end with those 64's will get me wellll down in the 9's. I'd love to go after a 8.99

 

saw your car at MIR not long ago at the test and tune/swap meet, was very impressed!!

 

I think twin 72's would be more suited for your cubes. They might come on stronger a little later but hell you dont even have gears and a good rear "YET" so id go a little larger so you dont have to again down the road.

 

thinking I may be blowing through the converter or else its just way to loose for my combo. Not sure but I think this combo may need something different which sucks because i just got this

 

You'll always want more .....
You're in the 1% club Dude. 700 Rwhp

I love watching you create this monster!!!!!

 

awesome man! I was waiting for this! I bet you have more in there too, bc 8psi I made 583 with pretty well the same driveline as u..th400 and 10 bolt (at the time) on a 383. This was a FAT tune also like 11.0afr.

I bet on 14psi You will see 700-750 no issues.

My TQ was only like 490 but i had a huge exhaust leak that made the turbo spool past 4000rpm. haha. I cant wait to finish mine!!!

Jay

 

With the TQ to HP ratio you are running at I would for sure consider bigger housings to let those turbo's breath. Car sounds awesome on the dyno.

 

Converter is too loose as well... I'm swapping housings here shortly, but debating on switching to 64-70mm as well

 

BTW nice job with your TT kit. It looks like though you have found a restriction somewhere in your kit. Difference between HP and TQ. Mustang Dynos aren't as glamorous as a dynoject but they are better for simulating street tuning. I had my tune done using a load dyno. Normally if the backpressure is greater then 2:1 and or there is a restricitions..the difference between tq and hp will increase as boost is increased.

Do you have a dyno sheet that I could see?

Another good place to tell (back pressure) is when the boost goes up and then drops back off in the higher rpms... spikes to 18#s then drops to 15#s between 5500-6500 rpms. This is sign of back pressure or a restriction. Backpressure can cause the turbine to slow down and then the boost drops off.

I will have to go back and read the specs on your turbo setup..as I can't remember if you went with a T3 or T4 flange. However even with a T3 flange the manifold should flow enough to make 800 rwhp. Like to see how the crossover at 5200 rpms looks. Did the hp dive off kind of like a TPI?

 

well with this converter being like 5500 stall speed when it was suppose to be 4000 or less, its hard to say if the graph is accurate or not.

I do have a printout but its not worth looking at. If i can find it i'll upload it here. Torque spikes on the converter hit, and falls rapidly afterwards. HP flatlines pretty much and does start to fall off. Its got to be a combination of restriction and overly rich tuning.

I did see some boost decrease but it was less than a 1 psi drop... Like it hit 18.5 then fell to 18. hit 12.8-12.9 then fell to 12.5... but at the track it doesnt to that.

Running T4 flange I just think .68 a/r is too small

 

Was the converted designed for the power level that you are working at? It will be very interesting when you get things sorted out.

 

A drop from 18.3 to 18 is basically nothing...your system is flowing good. Changing just the afr is all we changed to get my hp up. The first run at 18#s was like 785 rwhp with the afr @ 10.2...by time we got it to 11.8 it was making 834 rwhp on a load dyno. So you are definetly going to see at least a 40-50 rear hp increase when you lean the afr to about 11.7-11.9...which on a load dyno is fine. The reason tuners tune 11.5 on a dynojet is too build in some load that the car will see on the street or strip....and need to keep it under 13.1.

I am using PT52s, T4 flanges are big so you probably realize a .68 ar on a T3 is smaller then a .68 ar on a T4. With a TT it is like one Turbo per each side....two 4 cylinder engines.....in your case a 200cid per side.. I'm sure you know this but I chased .ars for a while on a different turbo kit that I had that had restrictions, but it behaved the way I described yours does not.

What RPM is your low boost threshold at...or where you reach max spool up? If it is like 3200-3500 rpms the hot side doesn't sound too restricted. It could also be the inlets but it is simple to pull off the inlet air filters and see if the issue goes away.

 

I cant tell, i hit the gas, converter flashes up to 5000+ rpm and its in full boost just about. Its ridiculous fast i can tell you that but this converter needs replaced before i can justify the .68 a/r housings. I'm going to try .96's since my power appeared to peak much earlier than it should and i saw oil coming out the valve cover grommet so i know its seeing some pressure.


Converter was specified for my motor, but it turned out horrible i think. I told them i expected peak hp at 5800 rpm and wanted to be in the 700whp range. He said the converter could handle anything i could throw at it. Well it appears to be stalling way too high.

I went from 640 to 690 with about 5 psi which is horrible, but the air fuel was very rich on the 690 run. I expect 750whp easily with leaner air fuel. I got a feeling it may be closer to 800 with 17 psi which is what i realllly wanted to see.