2017 Dyno results/upgrades

Jacob_Royer

SCCoA Member
Last year power was up a little from when Dave initially (279rwhp/12.70@107.7)tuned the car but still was not where i wanted it to be:




This year i upgraded to the Magnum powers abradive rotor pack and went from 33% od to 25% od. Also discovered a crack in the MPX case and it had trashed the last set of rotors and beat up the inside of the case pretty bad so i replaced it with a fresh mpIII Boost was still low IMO 12/13psi which was the same i saw with GTP rotors and 33% od. The other day i discovered a large crack in the back of my raised top! I had taken this off a parts car and just threw it on when i put the 4.2 in two years ago. I threw a stock top back on and instantly went to 16psi! The car felt much better but the tune was lean above 2.9v vmaf. After some runs and adding fuel i had it back into the realm of being safe. Saturday i took the car to Blakenship tuning for their annual spring dyno day. Here are the results! Note: This is a mustang dyno not a Dynojet like what i had the car on at the shootout so gains are likely alot higher.



Lee Blakenship told me that i am blowing through the converter pretty badly and highly recomended re-stalling it so i am going to try to do that this year. The stall speed is 3500+ now where it was originally meant to be 2800rpm! the converter was built for a very mild 3.8 and has always stalled higher with the 4.2 but now its kinda silly on stall speed. The car feels alot better than it ever did and i hope be in the lower 12s this year
 
Where does the converter flash to now on the street? Was the converter locked? Nice gain from sorting out the issues.
 
Not at all its way too much stall for 3.73/wide ratio/m90

I entirely disagree with that. That thought's a plague that needs to go away from SC land so y'all can be faster.

That's at least the stall you need to perform well. A different point/topic to make could be that there's too much total slip (not to be confused with stall speed) after the drivetrain speed catches up to the converter's drive speed. "Blowing through a converter" means that the stator can't hold the forces being applied by the converter pump, i.e. making too much HP for the design of the converter. If you're stopping at 3500 that means that your new power level was higher than originally intended, but that's one way to 'loosen' up a converter is an increase in power. Just as long as you don't have a lot of high speed slip.
 
Jacob,

Mine is supposed to be a 3500 stall too and it will flash to around 5400 which usually makes getting traction off the line very difficult (even with slicks). It hits very hard when you go WOT, but I think it would be a lot more enjoyable to drive on the street if it was about 500 rpm tighter.

dyno chart 040917.jpg

David
 
Jacob,

Mine is supposed tois very be a 3500 stall too and it will flash to around 5400 which usually makes getting traction off the line very difficult (even with slicks). It hits very hard when you go WOT, but I think it would be a lot more enjoyable to drive on the street if it was about 500 rpm tighter.

View attachment 66985

David



This gives me hope! It looks like our boost to hp ratio Is very simliar I just need a blower that will put 20psi to my junk! I am
planning on doing a 2.1l kenne bell once I sell the Cobra.
 
Not at all its way too much stall for 3.73/wide ratio/m90

A 373 gear ratio will actually soften the hit on the converter. The lower numerical gear ratio makes the converter work harder. My flash stall increased from 5200 to 5400 rpm just by switching from a 26" to 28" tire. Turbocharged though so load plays a bigger role on my boost curve.
 
Jacob,

Mine is supposed to be a 3500 stall too and it will flash to around 5400 which usually makes getting traction off the line very difficult (even with slicks). It hits very hard when you go WOT, but I think it would be a lot more enjoyable to drive on the street if it was about 500 rpm tighter.

That explains part of why she runs so well :)
 
That explains part of why she runs so well :)

Yeah...I'm not really unhappy with how high it flashes when I'm at the track, just feels a little too slippy when cruising around and generates more heat than I like. I think 3000 stall that flashed to around 5000 would feel much better and run a little cooler.

David
 
Yeah...I'm not really unhappy with how high it flashes when I'm at the track, just feels a little too slippy when cruising around and generates more heat than I like. I think 3000 stall that flashed to around 5000 would feel much better and run a little cooler.

David

I can understand that for sure. What converter do you have? Companies like PTC, Circle D, M&M, Coan and so on have mechanical lock up features that increase efficiencies of converters, thus reduced heating. Sometimes I wonder if money isn't invested into high efficiency AOD converters then that motivates people to use sub-par stall speeds that sacrifice performance that doesn't necessarily adversely affect streetability.
 
Congrats Jacob.

Just to pile onto the converter discussion. I essentially have the same convertor as Neibert (or he has the same as me, I had mine first:p). I love it at the track, but I too think I need to tighten it up a bit. It is also the reason my car performs well at the track, but sucks on a dyno. Since this is the first transmission I have had that has lasted, I'm afraid to change anything.
 
I can understand that for sure. What converter do you have? Companies like PTC, Circle D, M&M, Coan and so on have mechanical lock up features that increase efficiencies of converters, thus reduced heating. Sometimes I wonder if money isn't invested into high efficiency AOD converters then that motivates people to use sub-par stall speeds that sacrifice performance that doesn't necessarily adversely affect streetability.


Circle D doesn't advertise a converter for an AOD on their website but they do make them. Great converter in my opinion.
 
Congrats Jacob.

Just to pile onto the converter discussion. I essentially have the same convertor as Neibert (or he has the same as me, I had mine first:p). I love it at the track, but I too think I need to tighten it up a bit. It is also the reason my car performs well at the track, but sucks on a dyno. Since this is the first transmission I have had that has lasted, I'm afraid to change anything.



Mine is a 9" billet dirty dog 31spline (I have the billet input shaft). It will make you cry when you dyno the car lol.
I only made 213rwhp when it was running 13.70s and at 289rwhp i was going 12.70/107.7 i love how it does on the track
But it is really loose on the street. Mpg is beyond crappy I get 12ish lol i hope to see a low 12 this year!
 
I think you guys are confused. Nobody's converter here flashes that high. Sure it jumps to 5000rpm pretty quick on the dyno, but that is because you are already in 3rd going 50mph when you try to lock it up AND it's probably slipping the tires to boot. You all need to datalog your cars AT THE TRACK before starting these conversations. My 5.0 "flashes" as you say on the dyno to about 4800rpm, and anytime you mash the throttle on the street it hits 3500rpm instantly, but at the track with slicks on and from a stand still it flashes/stalls at 2800rpm. Period. You can't make it go over 2800rpm without moving the tires first.

Not saying some of you couldn't use lower stall speeds, but suggesting that it would be helpful to use correct terms correctly and to be quote actual data rather than perceptions based on fluid conditions. I don't think the converters are eating up as much HP as you guys seem to think either. Brian Whitfield's 4.2 routinely makes 380+rwhp through his AOD and runs low 12's. He has a loose converter too. There are others as well.
 
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