mike13

iTrader: (27)

I put my car on the dyno last weekend and it didn't go as planned, it looks like the converter couldn't hold the torque. The green line is the boost 16.9lbs. No tire spin, the 60lb injectors where at 80% duty cycle at a boost referenced 74psi fuel pressure .

TracyRR

iTrader: (8)

Oh crap! Is that what blowing throught the converter looks like on a dyno? How does it feel on the street?

MillsMotorvation

How is that a indication the stall is wrong, or not working. New to this trying to learn.

mike13

iTrader: (27)

It only made 445/410 hp/tq, when I checked my datalogs there was over a 800rpm difference in rpm to wheel speed at 5800 rpm. I good indication is as the boost starts really climbing the graph has all those up and downs like wheel spin. Looking at my injector duty cycle it should be in the 700rwhp range.

It's supposed to be a 4000-4200 stall but this was before the 383 and ST80, it was spec'd for much less hp and tq.

mike13

iTrader: (27)

How is it on the street? It's hard to tell because of the cold roads but kind of like it has a rubber driveshaft is the best I can discribe it. What's interesting is the boost comes in really high in the rpm on the dyno but on the street it builds boost completely different, much earlier.

Drewhelm

iTrader: (7)

Yep, blowing through the converter. Get a converter rated for the application. LOL Mine was rated at 550hp. It slipped at 670 and the ramps on the graph loked just like that. I am working on getting a new converter now...be ready to pay some $$$$ for a good converter.

mike13

iTrader: (27)

so your dynograph looked the same?

Hank Peabody

iTrader: (2)

Mines the exact same way, on the dyno it doesnt make power until up top, on the street its all smoke and two black marks at 2500rpm and 60mph, its really weird how that works.

mike13

iTrader: (27)

Is your stall speed alot higher then it's supposed to be?

Hank Peabody

iTrader: (2)

No its about 3000 stall, its tight on the street, but flashes to around 4000 if you floor it from a cruise rpm.

rotary1307cc

iTrader: (5)

yeah a i tried to dyno on dynojet while using a super cheap summit converter..... I knew i was blowing through it badly on the street but the dyno really made the car/converter do some weird stuff

excited for the new PTC and actually put the power to the ground

05HD

That is just what a Mustang dyno run looks like when you abort the run before the end of the test window. It is still recording as the engine decels hence the power readings jumping back and forth between 0 and whatever it was making on the way up. It doesn't show anything at all about your torque converter.

mike13

iTrader: (27)

Didn't abort the dyno run, we did 3 runs and they all looked the same way, first run they thought I might be spinning the tires, I datalogged all 3 runs and there was over a 800rpm difference between engine & tire rpm.

mike13

iTrader: (27)

Also if that where the case it would also show no boost instead of the boost climbing to 16lbs.

mike13

iTrader: (27)

What do you mean by weird?

Zombie

iTrader: (2)

My car made a whopping 520 rwhp (previous best was 470rwhp) on a Mustang dyno and runs low 10's with a 3850 race weight. We also had to apply about 8000lbs of load to accurately simulate street conditions with spoolup.

I'm glad I learned long ago to never believe dyno HP numbers and to only use them as tuning tools. I've seen several 700+ rwhp dyno charts that produce 12 sec time slips in the low 120mph range.

mike13

iTrader: (27)

That's funny, I pay more attention to my injector duty cycles to get me in the ballpark. The car made 445rwhp 800+rpm slippage and the duty cyle was 80% with 60lber's @74psi fuel pressure (boost referenced)

rotary1307cc

iTrader: (5)

well a dynojet would be different than what you used. The rollers are 5k lbs+ and it made the car act *** backwards compared to the street

on the graph power would hit early but stay low and constant. The engine would just sit at one RPM while the tire speed would slowly pick up

and word to zombie, dyno #'s don't mean dick

mike13

iTrader: (27)

Mine was the opposite, the rpm climbed quick but the mph was slower, kind of like it had a rubberband driveshaft.

rotary1307cc

iTrader: (5)

no the same,

my rpm would flash high and just sit there, and wheel speed came up slowly after

my power curve came quick from the flash but stayed low and flatish