a few changes!! how much improvement?
Thread Starter
Member
Joined: Jan 2008
Posts: 218
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From: Austin, Texas
Car: 86 iroc
Engine: 383HSR
Transmission: custom 700r
Axle/Gears: moser 9" 3.90
a few changes!! how much improvement?
well after my last trip to the track my car developed a bad vibration wich was soon followed by a strange but yet familiar rattling sound! i first was suspecting the drive shaft. but quickly ruled that out with a short test in drive w/the rear on stands! long story short, my flex plate was broken! for some reason this car loves to eat flexplates. ive broken 3 fp with 3 different engines and 2 trans and convertors. its verry strange!
anyways since it had to come apart i sprung for a 9.5" 3600 pi vigilante
should be in this weekend! i currently have a cheapie b&m 2400 stall.
i also will be replacing my megashifter that broke and the cable(now ill be able to hold first)!
and i put line-loc on the car.
my best time so far has been
1.77 60ft
7.96 1/8
86.74 1/8 mph
12.47 1/4
108.88 1/4 mph
just wondering if you guys think i can get 11's with the new conv!
i realy hope i can pull some 1.6-1.5 60 ft's
i have mt et radials, and lcarb's. the car hooks good at my local track too
sorry to write a book guys!
Thanks
anyways since it had to come apart i sprung for a 9.5" 3600 pi vigilante
should be in this weekend! i currently have a cheapie b&m 2400 stall.i also will be replacing my megashifter that broke and the cable(now ill be able to hold first)!
and i put line-loc on the car.
my best time so far has been
1.77 60ft
7.96 1/8
86.74 1/8 mph
12.47 1/4
108.88 1/4 mph
just wondering if you guys think i can get 11's with the new conv!
i realy hope i can pull some 1.6-1.5 60 ft's
i have mt et radials, and lcarb's. the car hooks good at my local track too
sorry to write a book guys!

Thanks
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Joined: Jul 1999
Posts: 17,271
Likes: 171
From: 51°N 114°W, 3500'
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: a few changes!! how much improvement?
With the Lunati 60103 camshaft, I wouldn't recommend more than a 3000 stall speed even with the NOS. 2800 would be better. That cam has an operating range of 1800-6200.
For street or street/strip, you want a stall speed about 500 rpm into the powerband. For full race you want about 1000 rpm into the powerband. 3600 stall will be far too much. Your 2400 stall is probably better for that camshaft.
For street or street/strip, you want a stall speed about 500 rpm into the powerband. For full race you want about 1000 rpm into the powerband. 3600 stall will be far too much. Your 2400 stall is probably better for that camshaft.
Thread Starter
Member
Joined: Jan 2008
Posts: 218
Likes: 0
From: Austin, Texas
Car: 86 iroc
Engine: 383HSR
Transmission: custom 700r
Axle/Gears: moser 9" 3.90
Re: a few changes!! how much improvement?
im going to be swapping the cam soon for a lunati 60105 it is 241/249 @.050
and should love the 3600!
im getting the converter from dana at probuilt he helped me pick it out and said that it should be good till i swap cams!
so you think its going to slow me down?
and should love the 3600!
im getting the converter from dana at probuilt he helped me pick it out and said that it should be good till i swap cams!
so you think its going to slow me down?
Moderator


Joined: Jul 1999
Posts: 17,271
Likes: 171
From: 51°N 114°W, 3500'
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: a few changes!! how much improvement?
The Lunati 60105 will like the 3600 stall.
Until you change the camshaft you probably won't see much if any improvement with a converter change. You may 60' better but because the converter will be stalling close to or just under your peak power, you may run slower because the converter won't lock up until you're over or near the top end of your power curve. Too much converter slip will slow you down just as bad as a converter with too low of a stall speed preventing the engine getting into it's powerband quicker.
According to Dyno 2000, my peak torque is around 4500. Peak HP is around 7400. I use a 6000 stall converter. I launch around 4500 and the rpms jump to 6000 then slowly climb as I go down the track. When I shift at 7400, the rpms drop to 6400 them climb back to 7400 when I cross the finish. Except for the brief time as I launch, the engine rpms are always above the converter's stall speed reducing converter slip as much as possible. Using a converter slip formula, I'm only getting around 4% slippage. I would consider anything under 10% as good.
Even with the high stall converter, I can easily drive around the pits at less than 2000 rpm however driving around at those slow speeds means the converter is really slipping. Converter slip means heat. Heat kills transmissions. Any converter with a higher than stock stall needs an aftermarket cooler to reduce the heat in the oil.
The purpose of a higher stall converter is to allow the engine to get into it's powerband quicker. The quicker it's into it's powerband, the faster it can use the power to move the vehicle. Too low of a stall means the converter is locked up at a lower rpm and it takes time to build rpm to where the engine makes it's best power. Too high of a stall and the engine shoots past it's peak power and the converter doesn't lock up until the powerband is decreasing as it goes over the curve. Either way, you're not staying in the area under the curve where you make the most power.
Read these.
http://www.hardtail.com/techtips/sel...converter.html
http://www.hardtail.com/techtips/torqueconverters.html
Until you change the camshaft you probably won't see much if any improvement with a converter change. You may 60' better but because the converter will be stalling close to or just under your peak power, you may run slower because the converter won't lock up until you're over or near the top end of your power curve. Too much converter slip will slow you down just as bad as a converter with too low of a stall speed preventing the engine getting into it's powerband quicker.
According to Dyno 2000, my peak torque is around 4500. Peak HP is around 7400. I use a 6000 stall converter. I launch around 4500 and the rpms jump to 6000 then slowly climb as I go down the track. When I shift at 7400, the rpms drop to 6400 them climb back to 7400 when I cross the finish. Except for the brief time as I launch, the engine rpms are always above the converter's stall speed reducing converter slip as much as possible. Using a converter slip formula, I'm only getting around 4% slippage. I would consider anything under 10% as good.
Even with the high stall converter, I can easily drive around the pits at less than 2000 rpm however driving around at those slow speeds means the converter is really slipping. Converter slip means heat. Heat kills transmissions. Any converter with a higher than stock stall needs an aftermarket cooler to reduce the heat in the oil.
The purpose of a higher stall converter is to allow the engine to get into it's powerband quicker. The quicker it's into it's powerband, the faster it can use the power to move the vehicle. Too low of a stall means the converter is locked up at a lower rpm and it takes time to build rpm to where the engine makes it's best power. Too high of a stall and the engine shoots past it's peak power and the converter doesn't lock up until the powerband is decreasing as it goes over the curve. Either way, you're not staying in the area under the curve where you make the most power.
Read these.
http://www.hardtail.com/techtips/sel...converter.html
http://www.hardtail.com/techtips/torqueconverters.html
Thread Starter
Member
Joined: Jan 2008
Posts: 218
Likes: 0
From: Austin, Texas
Car: 86 iroc
Engine: 383HSR
Transmission: custom 700r
Axle/Gears: moser 9" 3.90
Re: a few changes!! how much improvement?
with the cam i have now dyno 2k shows my peak tq @ 4500 rpm and peak hp @ 6000 rpm. this seems to be pretty accurate by my times and weight!
so the new conv will be 1000rpm under my pk.
so i think it should do well now and even better after the cam swap!
i think its good for an 11.99999999 but we will see!
so the new conv will be 1000rpm under my pk.
so i think it should do well now and even better after the cam swap!
i think its good for an 11.99999999 but we will see!
Senior Member
iTrader: (5)
Joined: May 2005
Posts: 831
Likes: 1
From: Midwest IL
Car: 1984 Z28
Engine: Alky 360
Transmission: TH400, Freakshow 9.5"
Axle/Gears: 9" 4.71
Re: a few changes!! how much improvement?
Not sure what your race weight is but there should be ALOT more left on the table with even that setup. I am running a 360 with the 60103. Home ported 416's, and have been 1.679 in the short times and the big end numbers were 12.38 @ 108.38. FWIW my race weight is 2910. I am running a 3500 convertor, but with my low weight i have never seen a flash over 3K.
Thread Starter
Member
Joined: Jan 2008
Posts: 218
Likes: 0
From: Austin, Texas
Car: 86 iroc
Engine: 383HSR
Transmission: custom 700r
Axle/Gears: moser 9" 3.90
Re: a few changes!! how much improvement?
the car weighs 3550#'s with me in it!
by my time and weight, it calculates out to 355rwhp and 426fwhp
and this junk b&m converter will only foot brake to about 1500 rpm and is extremely inconsistent with 60' times.
so this new conv should help that alot!
by my time and weight, it calculates out to 355rwhp and 426fwhp
and this junk b&m converter will only foot brake to about 1500 rpm and is extremely inconsistent with 60' times.
so this new conv should help that alot!
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Thread Starter
Member
Joined: Jan 2008
Posts: 218
Likes: 0
From: Austin, Texas
Car: 86 iroc
Engine: 383HSR
Transmission: custom 700r
Axle/Gears: moser 9" 3.90
Re: a few changes!! how much improvement?
kwik84 with the time you posted and weight, the math puts you right under 300fwhp so like 260rwh maybe!
my car is a little over 500lbs heavier and that extra weight makes more of a diff than you might think. hence my .09 slower et
add 500#'s to your car and watch what the et does
my car is a little over 500lbs heavier and that extra weight makes more of a diff than you might think. hence my .09 slower et
add 500#'s to your car and watch what the et does
Senior Member
iTrader: (5)
Joined: May 2005
Posts: 831
Likes: 1
From: Midwest IL
Car: 1984 Z28
Engine: Alky 360
Transmission: TH400, Freakshow 9.5"
Axle/Gears: 9" 4.71
Re: a few changes!! how much improvement?
Yeah this is pretty much a JY engine, the carb cost more than the rest of the engine...
but it works good for bracket racing. I was wondering what kind of weight you had, becuase that combination in a carbed form is pretty much what I am putting together for a second engine.
but it works good for bracket racing. I was wondering what kind of weight you had, becuase that combination in a carbed form is pretty much what I am putting together for a second engine. Thread Starter
Member
Joined: Jan 2008
Posts: 218
Likes: 0
From: Austin, Texas
Car: 86 iroc
Engine: 383HSR
Transmission: custom 700r
Axle/Gears: moser 9" 3.90
Re: a few changes!! how much improvement?
yeah a setup similar to mine with your weight should get you high 10's probably
Supreme Member
iTrader: (2)
Joined: Dec 2006
Posts: 5,538
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From: Hou. TX
Car: 86 TA, 91 B4C
Engine: 5.3, 4.8
Transmission: 4L80 4000, T56
Axle/Gears: 4.30 M12, 23.42 10 bolt
Re: a few changes!! how much improvement?
Let me see, with a manual trans, 1.8x 60 ft, i went 7.4x at 90 mph in the 1/8th and that tipped at 11.89 at 113 if i remember correct. That was a 383 with a Comp XE288HR. Ported 70 model "turbo heads" with 4.10 gears, Hooker super comps. Think race weight was 3620 lbs. Stock suspension too. Hope this helps you see where you need to be MPH wise for 11s. You should get it with the new cam and stall i think.
Thread Starter
Member
Joined: Jan 2008
Posts: 218
Likes: 0
From: Austin, Texas
Car: 86 iroc
Engine: 383HSR
Transmission: custom 700r
Axle/Gears: moser 9" 3.90
Re: a few changes!! how much improvement?
well i talked to pi today and they said that my converter was leaving today
and will be here fri! so i just have to stick it in and stab the trans. then hit the track!
and will be here fri! so i just have to stick it in and stab the trans. then hit the track! Thread Starter
Member
Joined: Jan 2008
Posts: 218
Likes: 0
From: Austin, Texas
Car: 86 iroc
Engine: 383HSR
Transmission: custom 700r
Axle/Gears: moser 9" 3.90
Re: a few changes!! how much improvement?
well i thought the flexplate was broke, i just got the trans out and the bellhousing has a big *** crack in it
and was allowing stuff to move around and cause the vibration and noise!
so im going to get it welded up and if they cant do it i guess i will be swaping internals into my spare case!
ive had one welded in the past with good results so my guy should be able to do it.
wish me luck guys!! im tryin to go racing tonight!
and was allowing stuff to move around and cause the vibration and noise!so im going to get it welded up and if they cant do it i guess i will be swaping internals into my spare case!
ive had one welded in the past with good results so my guy should be able to do it.
wish me luck guys!! im tryin to go racing tonight!
Joined: Jul 2004
Posts: 769
Likes: 51
From: Zebulon, nc
Car: 1990 GTA/1989 Iroc
Engine: L98/383
Transmission: 700r4/t56 magnum
Axle/Gears: 9"
Re: a few changes!! how much improvement?
I switched from a B&M 2400 to a PI 3200. The b&m wouldnt stall past 1500. I was very happy with the PI but i wish i had a little more stall in it. Im getting 1900 out of it. However, it is VERY consistent and i'd say it was worth only about a tenth.
Thread Starter
Member
Joined: Jan 2008
Posts: 218
Likes: 0
From: Austin, Texas
Car: 86 iroc
Engine: 383HSR
Transmission: custom 700r
Axle/Gears: moser 9" 3.90
Re: a few changes!! how much improvement?
here's the cracked bell housing

and the new converter , this thing is awesome the car feels totaly different. this would have to be one of the best mods ive done so far


and the new converter , this thing is awesome the car feels totaly different. this would have to be one of the best mods ive done so far

Re: a few changes!! how much improvement?
How soon till you hit the track? Call me crazy, but I usually set my cars up with a conveter that flashes close to the peak TQ. My LS1 car peaks TQ at 4900 RPM, my converter flashes about 4400-4600. I consistently hang the front tires on the launch... well I did until the 10 bolt decided to grenade. I think once you figure out how it likes to be foot braked, you will see a very nice gain. My car was lazy foot braking it to 1500 RPM, and I even tried just off idle - no dice. I started bringing it up to 2600-2700 RPM and my 60's dropped dramatically. But, each set up is different. It took me about 5-6 passes with my new set up to find the sweet spot.
Joined: Jul 2004
Posts: 769
Likes: 51
From: Zebulon, nc
Car: 1990 GTA/1989 Iroc
Engine: L98/383
Transmission: 700r4/t56 magnum
Axle/Gears: 9"
Re: a few changes!! how much improvement?
If youre breaking flywheels and bellhousings i would almost have to say there is an alignment issue somewhere. What kind of motor/trans mounts do you have? Does your torque arm still bolt to the tailshaft?
Thread Starter
Member
Joined: Jan 2008
Posts: 218
Likes: 0
From: Austin, Texas
Car: 86 iroc
Engine: 383HSR
Transmission: custom 700r
Axle/Gears: moser 9" 3.90
Re: a few changes!! how much improvement?
i went to the tack last fri after getting the converter in.
but i got there late and there was quite a few cars, so i only got one pass in!
the car usualy average's 1.8x 60' and i have one previous best of a 1.77.
right away first pass i pulled a 1.66 60' and from the vid i have it's almost pulling the front wheels
ended up running a 12.69 @ 107
im going to have to get used to when to shift cause with the new converter it gets up there a lot quicker, i feel that it will pick up a few 10th's once i get the shifts down!
also the conv is supposed to be a 3600 stall but it will flash to 4k and i can now footbrake to 2100-2200rpm now.
my mounts are all new poly mounts eng/trans
the torque arm is stock mounted with poly mount
i thought the same thing about alingment issues but have measured and every thing seems to be centred up pretty well.
i belive the bell housing cracked because the bolts had loosened up
so this time around i used loctite and lock washers so i shouldnt have that problem again. and the flex plates that broke were on the previous engine i thought this one was broke but it turned out to be the bell housing.
but i got there late and there was quite a few cars, so i only got one pass in!
the car usualy average's 1.8x 60' and i have one previous best of a 1.77.
right away first pass i pulled a 1.66 60' and from the vid i have it's almost pulling the front wheels
ended up running a 12.69 @ 107im going to have to get used to when to shift cause with the new converter it gets up there a lot quicker, i feel that it will pick up a few 10th's once i get the shifts down!
also the conv is supposed to be a 3600 stall but it will flash to 4k and i can now footbrake to 2100-2200rpm now.
my mounts are all new poly mounts eng/trans
the torque arm is stock mounted with poly mount
i thought the same thing about alingment issues but have measured and every thing seems to be centred up pretty well.
i belive the bell housing cracked because the bolts had loosened up
so this time around i used loctite and lock washers so i shouldnt have that problem again. and the flex plates that broke were on the previous engine i thought this one was broke but it turned out to be the bell housing.
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