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Discussion Starter #1
Anyone realize real-world improvements by going to a SR (1000 rpm shift-point increase) from an HR turbo cam and while running the same amount of boost...seeing ET and/or MPH improvements in the 1/4 mile?

Previous best was 8.40s @ 162 with HR shifting at 6800 rpm...looking to shift around 7800 rpm with SR set up.

Also, will a lower gear ratio (3.55s or 3.73s) be needed to realize the higher shift-point? I know the math behind it says YES, but wanted to hear some experiences with this. I'm currently running a 28" DR with 3.27 gears.
 

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If you look at some of Steve Morris engine dyno videos on You Tube.. You'll see some of the narliest turbo setup make peak power at around 7200 rpm.. Especially in a single turbo application..
 

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Discussion Starter #6
If you look at some of Steve Morris engine dyno videos on You Tube.. You'll see some of the narliest turbo setup make peak power at around 7200 rpm.. Especially in a single turbo application..
Most of his engines that I've watched videos on have been larger cubic inch motors...I'm only a 347. I would have thought it to be hard to make 1300 + Hp without turning some rpm on my combo??
 

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Discussion Starter #7
I personally don’t see why you’d necessarily need a solid roller to shift it there.
My old HR combo, I had Morel high rev HR lifters that were supposed to handle 8500 rpm. I probably should have saved a ton of money and just went with a hotter HR cam, but water under the bridge now...going to make this SR combo work one way or another.
 

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I’m going out on a limb with my suggestion which is fairly generic: If you are not in a traction limited situation, my experience is that more gear give more leverage and faster et’s. I usually shoot for a trap rpm 300 or so more than your shift rpm. If it is more and you are comfortable with it, that’s fine too. So if it were me, I would start with putting as much gear in it as you are comfortable with at the finish line. Again, if traction isn’t an issue.
 

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Discussion Starter #9
I’m going out on a limb with my suggestion which is fairly generic: If you are not in a traction limited situation, my experience is that more gear give more leverage and faster et’s. I usually shoot for a trap rpm 300 or so more than your shift rpm. If it is more and you are comfortable with it, that’s fine too. So if it were me, I would start with putting as much gear in it as you are comfortable with at the finish line. Again, if traction isn’t an issue.
I have given this some thought for sure. I've never really launched the car last year with much more than 8 psi boost...60's in the 1.29 to 1.33 range. I'm sure there was definitely some ET reduction in launching with more boost (quicker 60') alone. I'm running a 275 Pro Radial, which I'm sure, with the correct suspension settings, should net a low 1.2 or even a high 1.1x 60' once I can figure out higher boost launch. I'm not ramping boost in yet either...just launched at 8 psi and almost immediately jumping to 23 to 25 psi for the remainder of the run to net 8.40 to 8.50 ETs.
 

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I cant recall the exact figures but a friend of mine went from hyd roller to solid and made about the same peak power near the same rpm but the power held on after peak longer. Perhaps it was hyd lifters bleeding down or valve float. Not sure but the car did pick up a few mph overall and i think a couple tenths. It was in the 1300 whp range there before turning up the boost. Never dynod on high boost. Car was in the high 7’s at that time
 

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Starting line ratio (SLR) needs to be right and converter has to work correctly with a torque limited combo like yours. It definitely needs more rear gear. One of the cars I work on is full interior, all steel but hood, true stock suspension fox coupe on MT 275 Pro. 1.48 low gear, 4.10 rear gear (runs 1/8th mile) launch is with 22-24 psi and runs consistent 1.14 - 1.16sec 60ft times. All boost in by 1.5sec or less (38 - 40psi). Shift is ~8000 and about 8200-8400 thru the traps. Engine is 363 SBF, aluminum rods, hand ported Victor Jrs, Super Victor intake, small SR with decent lift in the low to mid .700's. Compression is between 9.5 to 10.0 and is on methanol now. Transmission, converter, dump system and gearing are the keys to unlocking the true potential of the small displacement combos. Converter is probably the most critical of that list IMHO. Pro Torque would be my #1 with Camron's #2. Your combo with a U9 Pro Torque converter would be my pick. Hope this helps.
 
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Discussion Starter #12
I cant recall the exact figures but a friend of mine went from hyd roller to solid and made about the same peak power near the same rpm but the power held on after peak longer. Perhaps it was hyd lifters bleeding down or valve float. Not sure but the car did pick up a few mph overall and i think a couple tenths. It was in the 1300 whp range there before turning up the boost. Never dynod on high boost. Car was in the high 7’s at that time
That's what I'm shooting for is high 7s. I'm not class racing or even doing No-Prep...just do it for fun. Personal goal I guess. I probably should have just kept my HR cam and concentrated more on the 60' to get the car in the 7s, but I always wanted a SR cam for some reason.
 

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Starting line ratio (SLR) needs to be right and converter has to work correctly with a torque limited combo like yours. It definitely needs more rear gear. One of the cars I work on is full interior, all steel but hood, true stock suspension fox coupe on MT 275 Pro. 1.48 low gear, 4.10 rear gear (runs 1/8th mile) launch is with 22-24 psi and runs consistent 1.14 - 1.16sec 60ft times. All boost in by 1.5sec or less (38 - 40psi). Shift is ~8000 and about 8200-8400 thru the traps. Engine is 363 SBF, aluminum rods, hand ported Victor Jrs, Super Victor intake, small SR with decent lift in the low to mid .700's. Compression is between 9.5 to 10.0 and is on methanol now. Transmission, converter, dump system and gearing are the keys to unlocking the true potential of the small displacement combos. Converter is probably the most critical of that list IMHO. Pro Torque would be my #1 with Camron's #2. Your combo with a U9 Pro Torque converter would be my pick. Hope this helps.
Good info TurboII! Thank you! Like I replied to Orr89rocz, I just built this car for cruising and personal goal 1/4 mile runs (fastest guy on the block through tail pipes bragging rights...ha). I started in this hobby (obsession!) back in 1990 and have been chipping away at it ever since. Hell, I can remember my 1st fox body 1/4 mile pass was a 15.30 I think! LOL! Now I'm trying to run 7s in a street cruiser...what the hell is wrong with me?! I digress! Anyways, I'm currently running a mid-range Rossler TH400 with the stock 2.48 1st gear. I also have a PTC converter that was spec'd for my car. My transmission is what has kept me from going more aggressive with my rear end gearing up to this point for fear of spin at the start line or, worse yet, spinning on the 1-2 or 2-3 shift and putting it into the wall. I do believe that with my new SR set-up that I will need a bit more gear to realize any benefit at the track. I'll try my current 3.27s and see how the converter behaves. Oh, I also upgraded to an external dump set-up on my TH400, so hopefully that helps a bit with starting line spool, etc. We will see. Hopefully, I'll have the car together in the next 6 weeks or so and get it to the dyno, then the track before the snow flies here in PA.
 

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Starting line ratio (SLR) needs to be right and converter has to work correctly with a torque limited combo like yours. It definitely needs more rear gear. One of the cars I work on is full interior, all steel but hood, true stock suspension fox coupe on MT 275 Pro. 1.48 low gear, 4.10 rear gear (runs 1/8th mile) launch is with 22-24 psi and runs consistent 1.14 - 1.16sec 60ft times. All boost in by 1.5sec or less (38 - 40psi). Shift is ~8000 and about 8200-8400 thru the traps. Engine is 363 SBF, aluminum rods, hand ported Victor Jrs, Super Victor intake, small SR with decent lift in the low to mid .700's. Compression is between 9.5 to 10.0 and is on methanol now. Transmission, converter, dump system and gearing are the keys to unlocking the true potential of the small displacement combos. Converter is probably the most critical of that list IMHO. Pro Torque would be my #1 with Camron's #2. Your combo with a U9 Pro Torque converter would be my pick. Hope this helps.
If you don't mind me asking: What is the fall back rpm of the converter and what two step rpm is being used at the launch?
 

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4400-4800rpm depending on track conditions. Shift extension is ~500rpm. The amazing part is when it couples out the back slip is 0 to 2% and its a non-lockup converter.
 

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4400-4800rpm depending on track conditions. Shift extension is ~500rpm. The amazing part is when it couples out the back slip is 0 to 2% and its a non-lockup converter.
Just so I am interpreting it correctly, it falls back to about 500 under the shift? So like 7500 rpm? If so my PTC acts about like that as well and slips about like that as the finish line as well. I was thinking maybe it was too loose....but maybe not.
 

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Starting line ratio (SLR) needs to be right and converter has to work correctly with a torque limited combo like yours. It definitely needs more rear gear. One of the cars I work on is full interior, all steel but hood, true stock suspension fox coupe on MT 275 Pro. 1.48 low gear, 4.10 rear gear (runs 1/8th mile) launch is with 22-24 psi and runs consistent 1.14 - 1.16sec 60ft times. All boost in by 1.5sec or less (38 - 40psi). Shift is ~8000 and about 8200-8400 thru the traps. Engine is 363 SBF, aluminum rods, hand ported Victor Jrs, Super Victor intake, small SR with decent lift in the low to mid .700's. Compression is between 9.5 to 10.0 and is on methanol now. Transmission, converter, dump system and gearing are the keys to unlocking the true potential of the small displacement combos. Converter is probably the most critical of that list IMHO. Pro Torque would be my #1 with Camron's #2. Your combo with a U9 Pro Torque converter would be my pick. Hope this helps.
Not trying to hi jack the thread do you mind sharing some et’s with this combo? It’s honestly very similar to mine and Vic jr heads and all...
 

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7secTurboLX

What turbos are you running? Where at in PA if you dont mind me asking?

Wheelsup

I also have a similar combo, a little smaller at 321" but Vic Jrs and all also... Should be done in a few weeks. Made a little over 500 to the tire in NA form on pump gas. Only new changes will be camshaft really, besides the S300's. I am running E85 blow through.
 

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Just so I am interpreting it correctly, it falls back to about 500 under the shift? So like 7500 rpm? If so my PTC acts about like that as well and slips about like that as the finish line as well. I was thinking maybe it was too loose....but maybe not.
Or perhaps I should ask true stall.
 

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Not trying to hi jack the thread do you mind sharing some et’s with this combo? It’s honestly very similar to mine and Vic jr heads and all...
Its has been 4.6X in decent air, 153mph or 154mph mabe a little faster. I don't go to the track with him very often. It has a Dart SHP block and I put fuel hoops in it, aluminum rods, rebalanced the crank that was not happy prior to my work on it. Whoever tried to balance it did a very poor job of it. It would beat up the bearings pretty bad before I fixed it. We did all this plus I built a new intake and injector setup when we changed it to methanol. I don't think we could have ever run it this hard on gas and not hurt it. It was about .35 slower on E85 or C16, 1.80 glide, 3.73 and A2W IC. Now its 550PPH Atomizers, Turboglide 1.48 first gear, 4.10, Cameron's converter. Still wet sump, timing chain, 1-5/8" shorty headers and had several different turbos on it. Currently a PT Pro Mod 98mm but no quicker than 94mm Forced Inductions turbo was. Its honestly out of head and camshaft. Heads are antique hand ported units off a friend's old Pro 5.0 engine. It is extremely quick for the sum of its parts, full stock interior except Kirkey front seats, all steel but hood, all glass, etc so its no lightweight either. 8.50 CM cage. Its amazing to see it launch with 24psi and be at 38 or 40 in 1sec and not knock the tires off or wheelstand. Sometimes tries to power wheelie about 300ft at top of 1st gear.
 
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