My SC can produce wheelspin from a standstill up until i'm going 30 mph, seemingly all in 1st gear (AOD) on 245/50 tires. Cant get any wheelspin in 2nd at all except when it's slightly wet outside. But i could get wheelspin up to 40-50 mph (sometimes) from standstill with the 225/60 stock tires which have about 1" larger diameter. For both cases is this normal behavior for an SC that has been heavily modified with bolt ons? Is my car producing a lot of low end torque or is it falling short compared to other highly modified SC's? Anyone here noted how much wheelspin can be produced without power braking or using a trans brake?
wheelspin question
- Thread starter hytorksc
- Start date
David Neibert
SCCoA Admin
To test the effectivness of mods, I sometimes take the car to a back road near my house and see how easily it spins the tires afterwards. For over a year now, I haven't even been able to use first in these test because it is too easy to hit the rev limiter. I usually just hit it hard at about the same time I shift into second (Lentech VB) and see how far I can keep them spinning. Since the car tends to get sideways I usually let off before they stop spinning.
If I want to do a really long burnout from a standstill or slow roll, I just shift into second while they are still spinning and the tires never even slow down. Most of the time I still have to let off because of the car getting sideways, but ocassionally I can keep it straight enough to ride it out for a couple hundred feet.
I think a better test is to see how fast I can be going on dry level pavement and still break the tires loose just by nailing the throttle. When it's a little cooler out I can go as fast as 50 mph in 3rd and smoke the tires when it down shifts to 2nd. Again, this causes the rear of the car to kick sideways and I usually chicken out long before they stop spinning.
I recently switched gears from 3.73 to 4.10 and much to my surprise it became harder to break the tires loose from a roll. I'm guessing that's because of the slower rotational speeds. They now grab and go unless doing under 40 mph. As expected they spin easier from a stop, but increasing rear tire width from 255 to 270 has helped a little.
It's more fun than the law allows, so don't get caught.
David
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So Dave-
I take it that your SC has ALOT of midrange and top end, and you have your high stall torque converter to take advantage of the higher revs. I'm still using mostly stock components (including exhaust) but i've always been afraid to install high flowing components for the possible loss of significant low end response. Do you still have low end, or does the high stall take care of that for you?
I take it that your SC has ALOT of midrange and top end, and you have your high stall torque converter to take advantage of the higher revs. I'm still using mostly stock components (including exhaust) but i've always been afraid to install high flowing components for the possible loss of significant low end response. Do you still have low end, or does the high stall take care of that for you?
XR7 Dave
Registered User
Assuming you have stock gears that would explain most of it. In first gear you have enough power to totally overwelm the tires but in second your lack of gear ratio is catching up with you and you don't quite have enough power to do it again. Lower rear end gears (higher number) would likely change that so you can light em in 2nd. 
David Neibert
SCCoA Admin
I switched to a lightweight higher stall converter because I expected a loss of bottom end power when making the last cam switch.
Well it worked fine until I installed an MPII blower case and MP inlet plenum, it gained lots of bottom end power and torque and the higher stall wasn't needed. With the engine's increased torque the flash stall is now a little over 3100 rpms. If you don't do a really long burnout at the track it's spins the 11.5" Mickey Thompson DOT slicks like I'm on regular street tires. I've had better results when holding the rpms at about 1300 to prevent the stall from flashing too high and spinning the tires.
More top end power does not necessarly mean less bottom end power. With a supercharger you can have both.
David
so does the flash rpm of the converter has alot to do with how much wheelspin will be produced?- does it allow the engine to spin in it's max torque band then catches on the wheels- keeping power high enough to continuiously spin the tires through the gears?
my stock converter is choking out most of my power and i know the stock exhaust ain't doing no good either. i was afraid to change the exhaust because the car is so damn heavy and needs all the low end it can get to respond and move. i thought that was what the SC was all about- what gave it the advantage. i mean after reading so many threads about how the SC is not a top end car, but yet so many have changed their exhausts and opened up flow so much that their power bands move above 3500 rpms with high HP at the wheels, i thought that if you open her up too much it would not be good for a street situation. if your SC can run 12's, 11's whatever, how does that feel in a street situation? You can get a chrysler K car to run 10's but that doesn't mean that an SC that runs 10's will feel the same- it might pull much harder in the mids but slow down at the top. Can you really compete or surpass performance other fast street cars with this setup if you lose what the SC is good at- the low end advantage? It's like a balancing act. If you move the power band up significantly, does it not take more time to wind up? Does the power to weight ratio exceed even a stock LS1 car or Z06 corvette when you go this far with modding the SC?
sorry about all the scatterbrain questions-
my stock converter is choking out most of my power and i know the stock exhaust ain't doing no good either. i was afraid to change the exhaust because the car is so damn heavy and needs all the low end it can get to respond and move. i thought that was what the SC was all about- what gave it the advantage. i mean after reading so many threads about how the SC is not a top end car, but yet so many have changed their exhausts and opened up flow so much that their power bands move above 3500 rpms with high HP at the wheels, i thought that if you open her up too much it would not be good for a street situation. if your SC can run 12's, 11's whatever, how does that feel in a street situation? You can get a chrysler K car to run 10's but that doesn't mean that an SC that runs 10's will feel the same- it might pull much harder in the mids but slow down at the top. Can you really compete or surpass performance other fast street cars with this setup if you lose what the SC is good at- the low end advantage? It's like a balancing act. If you move the power band up significantly, does it not take more time to wind up? Does the power to weight ratio exceed even a stock LS1 car or Z06 corvette when you go this far with modding the SC?
sorry about all the scatterbrain questions-
David Neibert
SCCoA Admin
Not a problem, and anyway some of the questions were not answered.
Yes..If the stall is close to the engines peak torque the launch will be harder and tend to spin the wheels easier. BTW, this is only useful on the track. If you hit the gas pedal too quick on the street it just sits there and spins, the average Caviler can get a car length or two jump on me, unless I ease into the gas.
You need more top end power to keep them spinning. Mine used to stop spinning when rpms reached about 4500, since switching cams again, that is when it really starts pulling hard. I would highly reccomend a 10" 2400-2500 stall non locking converter. It allows a little slack to get the rpms up quicker but it's not so loose that you give away too much power because of slipping. The non-locking is mainly for 3rd gear...it prevents bogging and maintains peak torque about 30% longer than a locking converter because of the slipping.
With the non locker you need more cooling and will give up getting third gear rubber, unless you have over 300 rwhp. It is however less stressfull on the transmission because the shift into third is cushioned by the slipping converter.
Yes it can which is why I can usually beat either one on the track or the street. I don't condone street racing, but once in a while I'll fool around with another car and get on it hard thru 1st and 2nd, but only at night (heard but not seen) and if there are no other cars around. Both cars usually spin the tires like crazy but don't really go very fast before letting off. Kind of like sparring instead of really fighting.
David
Yes..If the stall is close to the engines peak torque the launch will be harder and tend to spin the wheels easier. BTW, this is only useful on the track. If you hit the gas pedal too quick on the street it just sits there and spins, the average Caviler can get a car length or two jump on me, unless I ease into the gas.
You need more top end power to keep them spinning. Mine used to stop spinning when rpms reached about 4500, since switching cams again, that is when it really starts pulling hard. I would highly reccomend a 10" 2400-2500 stall non locking converter. It allows a little slack to get the rpms up quicker but it's not so loose that you give away too much power because of slipping. The non-locking is mainly for 3rd gear...it prevents bogging and maintains peak torque about 30% longer than a locking converter because of the slipping.
With the non locker you need more cooling and will give up getting third gear rubber, unless you have over 300 rwhp. It is however less stressfull on the transmission because the shift into third is cushioned by the slipping converter.
Yes it can which is why I can usually beat either one on the track or the street. I don't condone street racing, but once in a while I'll fool around with another car and get on it hard thru 1st and 2nd, but only at night (heard but not seen) and if there are no other cars around. Both cars usually spin the tires like crazy but don't really go very fast before letting off. Kind of like sparring instead of really fighting.
David
I can burn the tires in 1 2 3 sometimes a little in fourth and one time they spun when I shifted to 5 but it was really f'ing wet(the pavement) and tires too. I got 2.73 on the back saves gas but not enough take off power. what gear ratio would you guys recommend for an 89 5 speed. 3.08-3.27?
David Neibert
SCCoA Admin
3.27s
David
David
David,
thanks again for your input- and thanks to the others.
I need to re-align my perceptions about the SC after reading all this. i haven't tested mine on a dyno yet, but based on the way my car behaves i would estimate that it's generating 200rwhp and 300rwt with the mods i have. So i think i need to do the following upgrades to get near your output level;
-full exhaust (excluding headers)
-bigger intercooler (or at least wrap exhaust headers to reduce heat on lower IC tube)
-wrap stock lower IC tube to protect from header heat up(?)
-10% lightweight OD pulley (or jackshaft pulley setup)
-lentech vb kit
-10" lightweight 2400-2500 stall converter
-ported heads (intake/exhaust)
-a mild cam upgrade
-255/50-16 tires (stock diameter, but much wider)
-do i need a hardened transmission shaft?
-trans cooler
here's what i already have;
-custom 3" intake setup w-K&N, with 73mm MAF, 70mm TB
-max ported m90, enlarged both ends
-MP raised top
-underdrive pulleys
-IC fan
-custom cooling fan setup
-180 degree thermostat
-ported IC tubes/intake
-iridium plugs
-ported exhaust collectors
-245/50-16 tires
-made a whole bunch of fine adjustments and optimizations
thanks again for your input- and thanks to the others.
I need to re-align my perceptions about the SC after reading all this. i haven't tested mine on a dyno yet, but based on the way my car behaves i would estimate that it's generating 200rwhp and 300rwt with the mods i have. So i think i need to do the following upgrades to get near your output level;
-full exhaust (excluding headers)
-bigger intercooler (or at least wrap exhaust headers to reduce heat on lower IC tube)
-wrap stock lower IC tube to protect from header heat up(?)
-10% lightweight OD pulley (or jackshaft pulley setup)
-lentech vb kit
-10" lightweight 2400-2500 stall converter
-ported heads (intake/exhaust)
-a mild cam upgrade
-255/50-16 tires (stock diameter, but much wider)
-do i need a hardened transmission shaft?
-trans cooler
here's what i already have;
-custom 3" intake setup w-K&N, with 73mm MAF, 70mm TB
-max ported m90, enlarged both ends
-MP raised top
-underdrive pulleys
-IC fan
-custom cooling fan setup
-180 degree thermostat
-ported IC tubes/intake
-iridium plugs
-ported exhaust collectors
-245/50-16 tires
-made a whole bunch of fine adjustments and optimizations
OK 3.08 or 3.27? 2 answers and 2 different ones.
I just wanna feel more pull from the car, but I don't wanna raise the rpm too much on the highway. I know the 3.27 are gonna raise the rpm more than 3.08, but if it's just 200 or 250 more rpm than 3.08 I would put 3.27 . how much rpm am I gonna see on the highway from the 2 ratios? right now I can go 80 at 2000 rpm. Oh BTW I had my car at 3500 or 3600 rpm last night in 5th gear, how fast do you think I was going, it seemed very fast.
I was thinking lets see
2000 at 80mph so half is 1000 40mph so 3000 is 120 and half of 1000 rpm is 20mph so I was going like 133mph does that sound right?
I just wanna feel more pull from the car, but I don't wanna raise the rpm too much on the highway. I know the 3.27 are gonna raise the rpm more than 3.08, but if it's just 200 or 250 more rpm than 3.08 I would put 3.27 . how much rpm am I gonna see on the highway from the 2 ratios? right now I can go 80 at 2000 rpm. Oh BTW I had my car at 3500 or 3600 rpm last night in 5th gear, how fast do you think I was going, it seemed very fast.
I was thinking lets see
2000 at 80mph so half is 1000 40mph so 3000 is 120 and half of 1000 rpm is 20mph so I was going like 133mph does that sound right?