SOTP Modifications with a 700R4
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 878
Likes: 2
From: BC
SOTP Modifications with a 700R4
I've recently built a 383, with most of the bells and iwhistles and it pulls very well but it just doesn't have the punch that I was expecting. A friend has built a similar engine with a 6spd manual with 3.45 rear behind it and the difference is amazing... now I know that this is really SOTP and over some timed video's etc theres not a lot to choose between them...
What can I do to get a better SOTP feeling? I'm running an LT1 intake and a high duration cam, things really start to get going around 3,500 and upwards...
I keep wondering about stall speed and rear end gears but don't know which way to go, I don't want a converter thats going to feel really lose as most of my driving is on the street, or road track.
I'm running a 3.07 rear end and a 2,200 stall at the moment...
1st gear is pretty useless as I just make smoke,
2nd gear is good and feels the best but I struggle to get back down into it and don't feel overly confident slamming it in manually.
3rd gear just seems soooo damn long...
4th is rarely used when "on it"...
I wonder about going with a shorter rear end, 3.45 or something but then 1st and probably 2nd are going to be less usefull, but it might bring 4th gear into the equasion?
Idea's and suggestions please...
What can I do to get a better SOTP feeling? I'm running an LT1 intake and a high duration cam, things really start to get going around 3,500 and upwards...
I keep wondering about stall speed and rear end gears but don't know which way to go, I don't want a converter thats going to feel really lose as most of my driving is on the street, or road track.
I'm running a 3.07 rear end and a 2,200 stall at the moment...
1st gear is pretty useless as I just make smoke,
2nd gear is good and feels the best but I struggle to get back down into it and don't feel overly confident slamming it in manually.
3rd gear just seems soooo damn long...
4th is rarely used when "on it"...
I wonder about going with a shorter rear end, 3.45 or something but then 1st and probably 2nd are going to be less usefull, but it might bring 4th gear into the equasion?
Idea's and suggestions please...
Melting Slicks
Joined: Jan 2008
Posts: 2,065
Likes: 1
From: Jasper Texas
sounds like a similar build to mine. I've got 3.73s in my rear now...but I'm about to have 3.45s...I'll let you know how they feel. Gears and a stall should do wonders for you. My SOTP feeling is amazing after 2K rpms, and after about 4K,....weeeeeeeeeeeeeeeeee!
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 878
Likes: 2
From: BC
very intersted to see how you think it goes! I think I get at too low an RPM in 3rd too often, if I blast through all the gears then it feels quick but most of my acceleration starts at 60mph, it wont auto shift to 2nd and I'm worried about slamming it in manually...
Edit: even if there was a way I could make it kick down at higher RPM's that may help?
Edit: even if there was a way I could make it kick down at higher RPM's that may help?
Melting Slicks
Joined: Jan 2008
Posts: 2,065
Likes: 1
From: Jasper Texas
What rpm are you shifting at right now?
I don't know exactly what you've got going on there...but when racing, I manually shift at ~6800rpms, but the transmission is built to handle that, and the engine...
The one thing I hated about the 3.73s is how short first and second were, shifted at 40mph and then a lil' under 80. The 3.45s should widen it up some, but I'll still have the power to pull through the gear quickly.
I don't know exactly what you've got going on there...but when racing, I manually shift at ~6800rpms, but the transmission is built to handle that, and the engine...
The one thing I hated about the 3.73s is how short first and second were, shifted at 40mph and then a lil' under 80. The 3.45s should widen it up some, but I'll still have the power to pull through the gear quickly.
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 878
Likes: 2
From: BC
like i said going through the gears its OK - I manually shift around 6,000 rpm with a limiter at 6,200...
its the time when I'm just out on the open road sat at just under 60mph or something and I want to overtake - it just seems flat in 3rd...
its the time when I'm just out on the open road sat at just under 60mph or something and I want to overtake - it just seems flat in 3rd...
Burning Brakes
Joined: Nov 2004
Posts: 800
Likes: 3
From: Port Orange FL
I am going to go say you will see a big smile on your face with sticky tires. With my street tires 1st gear (the hardest accellerating one) is almost useless, as at anything under about 30 MPH, if I punch it the tires go up in smoke, and the car goes nowhere. With my drag radials punching it in 1st is like being launched from a cannon. 
A quality higher stall converter will help that third gear condition as it will allow the motor to be in that powerband all the time. But you have to hook that power up first.
Roy
A quality higher stall converter will help that third gear condition as it will allow the motor to be in that powerband all the time. But you have to hook that power up first.
Roy
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Le Mans Master
Joined: Aug 2004
Posts: 5,141
Likes: 7
From: Metairie Louisiana
I'm running a 2800 stall vigilante with the 3.07 rear in my daily driver. It is very streetable. You don't even realize it's in there until you put it to the floor.
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 878
Likes: 2
From: BC
1985 C4 Corvette
Grand Sport Paint Theme
GM ZR-1 Wheels 17x9
Lowered 1"
Iggee Black Seat Covers
Gen1 Small Block Chevy, 2 Pc Rear/ 2 Bolt Main
GM LT1 Intake Converted for Gen1 Heads
AFR 195 Eliminator Heads 75cc Assembled
ARP Rocker Studs / Mr Gasket Rocker Arm Locknuts
Comp Cams Forged 1.6:1 Roller Rockers
Comp Cams 5/16 .80 Hardend Pushrods -.100
Comp Cams Retro Roller Lifters
Comp Cams LT1 Hyd Roller Cam 230/244 .544/.577 @.50
Jegs 9 Keyway, Double Roller, Thrust Bearing Timing Set
Scat 9000 Cast 3.75 Stroke Crank
Scat I-beam forged 4340 5.7" ARP Rod Bolts
Claimer FlatTop Hypereutectic Pistons
Clevite Bearings Throughout
Jegs High Pressure/Flow Oil Pump
Scat Performance 8" Damper
Scat 168 Tooth Flex Plate
Hedman Long Tube Headers
Full LT1 Exhaust System, Cat-less
700R4 Rebuilt & Uprated with ALTO Frictions
2,200RPM Stall Torque Converter with LockUp
3.07 Perfromance Ratio, Dana36 Differential
An Desktop Dyno guesstimate:
Grand Sport Paint Theme
GM ZR-1 Wheels 17x9
Lowered 1"
Iggee Black Seat Covers
Gen1 Small Block Chevy, 2 Pc Rear/ 2 Bolt Main
GM LT1 Intake Converted for Gen1 Heads
AFR 195 Eliminator Heads 75cc Assembled
ARP Rocker Studs / Mr Gasket Rocker Arm Locknuts
Comp Cams Forged 1.6:1 Roller Rockers
Comp Cams 5/16 .80 Hardend Pushrods -.100
Comp Cams Retro Roller Lifters
Comp Cams LT1 Hyd Roller Cam 230/244 .544/.577 @.50
Jegs 9 Keyway, Double Roller, Thrust Bearing Timing Set
Scat 9000 Cast 3.75 Stroke Crank
Scat I-beam forged 4340 5.7" ARP Rod Bolts
Claimer FlatTop Hypereutectic Pistons
Clevite Bearings Throughout
Jegs High Pressure/Flow Oil Pump
Scat Performance 8" Damper
Scat 168 Tooth Flex Plate
Hedman Long Tube Headers
Full LT1 Exhaust System, Cat-less
700R4 Rebuilt & Uprated with ALTO Frictions
2,200RPM Stall Torque Converter with LockUp
3.07 Perfromance Ratio, Dana36 Differential
An Desktop Dyno guesstimate:
Last edited by dan_t; Aug 19, 2008 at 05:09 AM.
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 878
Likes: 2
From: BC
I guess I didn't initially go for a higher stall as I just assumed that it would be more for the "launch" than road driving... I'm not worried about a hard launch but I do want a nice punch when I'm on the road...
Burning Brakes
Joined: Oct 2004
Posts: 1,019
Likes: 1
From: Weymouth Dorset
[QUOTE=dan_t;1566761803]I've recently built a 383, with most of the bells and iwhistles and it pulls very well but it just doesn't have the punch that I was expecting. A friend has built a similar engine with a 6spd manual with 3.45 rear behind it and the difference is amazing... QUOTE]
3.73 nearly got it right mate
3.73 nearly got it right mate
LOL
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
The 9.5 inch units excell for sotp improvements. Lighter, and quicker to react, therefore less slushy than a typical 12 incher.
Safety Car
Joined: Jun 2000
Posts: 4,870
Likes: 25
From: Long Island, NY
That along with your 2200 rpm stall convertor will make the car FEEL lazy.
But, I am sure it is faster than before !
My old TPI setup felt much better on the street than the current Miniram setup.
Put a 3800 rpms stall in there and see the differance.
Vic
Race Director
Joined: Jun 2001
Posts: 10,956
Likes: 680
From: Marlboro country MA
My 383 LT1 combination feels just right. 60 foot times are regularly under 1.6 seconds, and quarter mile times in the 11's. The right combo makes all the difference. See sig for details.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Have almost identical 383 combo as you. Ran in fresh motor with big tube TPI setup off my old 350; kick **** SOTP.
Changed to HSR with same tune ,SOTP; nowhere as good
but half a sec faster on the 1/4 .Dialing out some of the bottom end torque of a 383 is actually benefical for traction purposes.