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I'm gonna throw another 1-2 lbs. at it and if there's no knock and fuel is good I'll probably leave it for pump gas.
Timing was at 12 degrees in that area according to the data log.
Sounds good. Be interesting to see how much your shift rpm drop changes with another 1-2 lbs. Overall, your convertor looks like it is working pretty well. I would think slightly tight would make for a better street driver than something too loose.
If boost doesn't allow less of a drop RPM wise, I'd shift it 100-200rpm higher even. Would be nice to not dip below 6k IMO. Actually easier on things. Can also run low viscosity hygard. It will loosen it up 100-200rpm.
Sounds good. Be interesting to see how much your shift rpm drop changes with another 1-2 lbs. Overall, your convertor looks like it is working pretty well. I would think slightly tight would make for a better street driver than something too loose.
I noticed an immediate difference on the 2-3 shift after raising the shift rpm, it's a quick, solid shift where before it was less noticeable and felt slushy so that was really nice.
If boost doesn't allow less of a drop RPM wise, I'd shift it 100-200rpm higher even. Would be nice to not dip below 6k IMO. Actually easier on things. Can also run low viscosity hygard. It will loosen it up 100-200rpm.
I'm not sure how much farther I'll be able to push pump fuel, guessing I'll probably start seeing knock in the 16-17lbs. range but I'd love to keep going up into the 18-20 lb. range if possible.
So set my shift light up to 7,200-7,300rpm if more boost doesn't loosen it up, hopefully it will.
I'll keep the LV Hygard in mind too since I'll be changing the oil on the trans this winter regardless.
I think the next step will be to start mixing some pump/meth and continuing to turn it up. 😏
So taking this to the next step as the car gets faster, how would a gear change from 3.50 to 3.25 affect how the converter operates?
Would the 3.25 gear reduce gear drop and increase slip on the big end?
More gear just loads everything harder. Converter would slip more. I wouldn't run a 3.25 gear. 3.50 is a lot of gear for your combo IMO. Too much gear and the converter will just hang and never couple correctly.
More gear just loads everything harder. Converter would slip more. I wouldn't run a 3.25 gear. 3.50 is a lot of gear for your combo IMO. Too much gear and the converter will just hang and never couple correctly.
Agree with this. 3.25 is crazy tall unless youre running a short tire.
So taking this to the next step as the car gets faster, how would a gear change from 3.50 to 3.25 affect how the converter operates?
Would the 3.25 gear reduce gear drop and increase slip on the big end?
It won’t affect gear drop at all. Been there, done that.
As with most things performance related, I think it varies depending on application.
Going from a 3.10 gear in my car with 29” tires, glide, and pretty tight 16 stator 9.5. I saw def improvements in shift drop each time (less drop) I went shorter on the gear. Ending up with a 3.70 and 28” tire eventually for my best ET/run. (at my power/weight on my specific setup)
I cam from a turbo buick back ground and built my first turbo LS in 2012. So I built it like a turbo buick, not knowing any better. Huge gear, low rpm, big boost. It ran ok shifting it at 6500rpm. The RPM would just table top and hang while slowly accelerating, not doing much work. It was enough for some ok passes, but about 1-1.5 seconds from where it should have been IMO. Every time I shortened the gear and went looser on the converter I picked up. IMO you want as much mechanical advantage with gearing as possible. All this “turbo cars need load” stuff is BS. IMO, the only reason a turbo car needs a 3.25 is if it’s trapping 200+…. Or running mile events… or a highway roll racer/cruiser. Otherwise gear it to run out of RPM at the 1/4 (or as close to it as possible).
Interesting, after seeing what happened with the converter, I have no intention of doing this anytime soon, I was more curious than anything if for some reason I ran out of rpm in the 1/4 mile.
Using the Wallace calculators (not sure on their accuracy lol), I should currently have enough to go 165mph @ 7,000rpm in the quarter which should be good for mid 8's which is right where I wanna be on high boost, 157mph @ 6,500rpm which should be low, low to 9's which if I can do that on pump gas, I'll be pretty happy.
Appreciate all the help guys!
Have to figure in converter slippage as well. Those MPH VS ET estimates seem a bit off. High 8’s at 152ish. Mid 8’s at 155-160ish. That’s with decent 1.3x 60’s and moderate 5.6-5.8 1/8th times.
More gear just loads everything harder. Converter would slip more. I wouldn't run a 3.25 gear. 3.50 is a lot of gear for your combo IMO. Too much gear and the converter will just hang and never couple correctly.
Originally Posted by ddnspider
Agree with this. 3.25 is crazy tall unless youre running a short tire.
Originally Posted by Forcefed86
Have to figure in converter slippage as well. Those MPH VS ET estimates seem a bit off. High 8’s at 152ish. Mid 8’s at 155-160ish. That’s with decent 1.3x 60’s and moderate 5.6-5.8 1/8th times.
That's kinda what I thought, I thought they seemed a bit high and slip wasn't part of the equation.
I was seeing about 7% slip before I raised the boost level so its probably still in that range or a little higher so using the calculator at 7,000rpm, 3.50 gear, 28" tire, 1:1 third gear and 7% slip nets me a top speed of 155.70 mph, 10% is 151.46 mph.
I think if I get the short game dialed in I have enough gear currently to get into the 8's.
I wrote converter slip math in HPT based on mph and rpm.
Last pass I made.
Converter flashes to 6100.
Shift both gears at 7000, drops back to 6200.
Finish line shows 6700, mph shows 158, converter slip 7.6%.
Time slip showed 157.7
I lift right at the stripe.
I wrote converter slip math in HPT based on mph and rpm.
Last pass I made.
Converter flashes to 6100.
Shift both gears at 7000, drops back to 6200.
Finish line shows 6700, mph shows 158, converter slip 7.6%.
Time slip showed 157.7
I lift right at the stripe.
3.31 gears, MT 275 pro
PTC 9.5 17 stator
I don’t think radials grow very much.
See initially this makes me think I need more gear to get into that mph range but it doesn't change the fact that with my current converter/shift drop, I'll still need to rev the engine higher to avoid falling into the peak torque range, a taller rear gear won't change that, only reduce rpm at the stripe. (thinking out loud at this point lol)
I'm a little surprised you aren't spinning that 5.3 higher than 7,000 rpm.
@RonSSNova I used the equation from the TCI Converter Slip calculator to create a channel on HP Tuners.
Since I was already monitoring MPH and RPM, should this work when I plug it in or do I have to do a new data log?
Or did I screw this up since it doesn't work lol?
There is a space between * and 336 as well.
I rarely even hit 7 in low. I suck at that shift. Some of that is being gun shy that it’s going to wheelie. Many times I shift it at 6 and the data looks like I have a powerglide. 😊
Ive done the 2-3 shift at 7400 and it makes no difference in et or mph. So no sense doing that.
The valve springs are Tooley Platinum duals, but have been in there 10 years. I ought to test them.
I don’t think it’s possible to know where the torque peak is on these things is unless you have a stick shift, or dyno it with the converter locked. It’s not something I even think about.
I wrote converter slip math in HPT based on mph and rpm.
Last pass I made.
Converter flashes to 6100.
Shift both gears at 7000, drops back to 6200.
Finish line shows 6700, mph shows 158, converter slip 7.6%.
Time slip showed 157.7
I lift right at the stripe.
3.31 gears, MT 275 pro
PTC 9.5 17 stator
I don’t think radials grow very much.
I have the same gear, converter and a glide with my 5.3 and s475. My fallback is to 5300 no matter what I shift at and I’m at 23.5 psi. My ****’s weak!
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