RPMs deep in the red zone, Still pulls hard!! ??
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Melting Slicks
Joined: Jul 2004
Posts: 2,695
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From: Chicago Illinois
RPMs deep in the red zone, Still pulls hard!! ??
Opend her up today for the first time after head cam swap and she pulls up high like never befor. I noticed my rpm gauge is tacked all the way and the car was still pulling good 
but Im concerned if this is a good thing or is it time for me to let of the gas. 93 LT1 2400stall 3.73. atomatic. I was doing around 135. If the car is still pulling am I ok then in reguards to the rpms. My rpm gauge only goes up to 6000.
but Im concerned if this is a good thing or is it time for me to let of the gas. 93 LT1 2400stall 3.73. atomatic. I was doing around 135. If the car is still pulling am I ok then in reguards to the rpms. My rpm gauge only goes up to 6000.
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 2,695
Likes: 0
From: Chicago Illinois
Originally Posted by bogus
well... did you have the rev limiter updated?
what all did you put on the motor? I assume roller rockers? that kinda stuff?
if so, your ok.
what all did you put on the motor? I assume roller rockers? that kinda stuff?
if so, your ok.
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
Originally Posted by Admiral94
You might be pushing it by reving to 6700 RPM on a stock bottom end. You might want to lower the limiter to 6500 RPM. Now you just need to get yourself an LT4 tach that reads up to 8k RPM.
I agree with above on the RPM--on the LT1 I would not exceed 6500 certainly and 6200-6300 is a better rev limiter. Depends on usage too--if you are road racing it and spending a lot of time up there--keep it below
6000. Auto-x too. For drag race you can push it. Just don't spend any dwell time up at 6000 or higher.
This RPM issue was why i went with a mild cam in my LT1, along with emissions.
Racer
Joined: Sep 2005
Posts: 344
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From: Duncanville Texas
LT4 tach
Umm.....yea good luck with the finding the LT4 gauges reasonable guys. Like an idiot ebayed the only one I had when I parted out a 96 CE. Supresed the heck out of me when It went to over $600!! 
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Safety Car
Joined: Dec 2004
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From: Poop land
Originally Posted by C4forlife
Umm.....yea good luck with the finding the LT4 gauges reasonable guys. Like an idiot ebayed the only one I had when I parted out a 96 CE. Supresed the heck out of me when It went to over $600!!
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 2,695
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From: Chicago Illinois
Originally Posted by STL94LT1
You might install a shift-light, to let you know how high you are going in the rpm range. I have my shift-light set at 6200 rpms, and my fuel cut-off set at 6500.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Originally Posted by bobmic93
Everything involved with your typical h/c swap.(behive, 1.6,opti, timming chain,30svo 52tb rev set at 6700) The tune needs more work but its only going to get better. 1 3/4 EM headers,xpipe ,no cats are going on Friday. Im not used to having power up that high and without knowing what rpm your at I dont want to jeapordize anything. I havent even brought it home yet from the installers shop.
Do you have emissions testing in Chicago? If so, you WILL NOT PASS the sniffer without some.
I would install a pair of highflow bullet cats, Carsound or Random Tech. About $150 each, top $$.
Instructor
Joined: Apr 2004
Posts: 161
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From: fl
Originally Posted by bobmic93
If the car is still pulling am I ok then in reguards to the rpms. My rpm gauge only goes up to 6000.
Last edited by 95NOSvette; Feb 23, 2006 at 04:36 PM.
Elite Torch Red Member
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From: Exit 89 GSP,Lakewood,NJ The Land Of Mojo
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I shift my car way past the redline. The factory tachs are off by as much as 500 rpm. Mine is off by maybe 200 or so, just guessing. But the factory fuel cutoff is supposed to be at 5800 and I'm going past that on my tach.
http://temp.corvetteforum.net/c4/mrmojo2//shiftvid1.wmv
Click here for the hell of it
http://temp.corvetteforum.net/c4/mrmojo2//shiftvid1.wmv
Click here for the hell of it
Melting Slicks
Joined: Aug 2003
Posts: 3,413
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From: Lakeville MI
With 3.73s in OD (0.70) you should be around 157 mph at 5500 rpm. Or around 177 mph at 6200 rpm.
6500 in 3rd should be 130 mph.
Sure you don't have 4.10s. Maybe your converter is slipping alot.
Me thinks, you're still in third. You may have some minor speedo-error.
6500 in 3rd should be 130 mph.
Sure you don't have 4.10s. Maybe your converter is slipping alot.
Me thinks, you're still in third. You may have some minor speedo-error.
Last edited by tequilaboy; Feb 23, 2006 at 04:59 PM.
Elite Torch Red Member
Joined: Sep 1999
Posts: 57,805
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From: Exit 89 GSP,Lakewood,NJ The Land Of Mojo
Cental/South NJ Events Coordinator
CI 1-2-3-4-5-6-7-8-9-10-11-12 Vet
CI-II Burnout & Drag Champ
St. Jude Donor '03-'04-'05-'06-'07
Originally Posted by curtismoff
what road could you do over 150 mph on,you guys are 
Thread Starter
Melting Slicks
Joined: Jul 2004
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From: Chicago Illinois
Originally Posted by tequilaboy
With 3.73s in OD (0.70) you should be around 157 mph at 5500 rpm. Or around 177 mph at 6200 rpm.
6500 in 3rd should be 130 mph.
Sure you don't have 4.10s. Maybe your converter is slipping alot.
Me thinks, you're still in third. You may have some minor speedo-error.
6500 in 3rd should be 130 mph.
Sure you don't have 4.10s. Maybe your converter is slipping alot.
Me thinks, you're still in third. You may have some minor speedo-error.
Melting Slicks
Joined: Aug 2003
Posts: 3,413
Likes: 404
From: Lakeville MI
The rpm vs speed data that I posted was extrapolated from my datamaster logs taken during 4th gear pulls on the dyno, and on the road. I have 4th gear data up to about 114 mph, from the dyno. My on road data is also consistent with the dyno data, but at lower speeds.
I have 3.73 gears and I have calibrated my speedometer/dakota digital sgi-5 interface, with respect to a racelogic vbox gps based data aquisition system, so I know the speedo is on the money. I have 275/40R17 Nitto 555Rs.
I assume your tire rolling radius is similar 811 revs/mile or so, but this could be an additional source of error if you have 285s or 315s, but they are all pretty close in terms of rolling radius.
The rpm data on my logs is a bit noisy, but the average rpm at 110 mph is 5500 rpm in 4th gear. Therefore:
110 mph/0.70 = 157 mph
130 mph/110 mph X 5500 rpm = 6500 rpm
You get the idea.
I have 3.73 gears and I have calibrated my speedometer/dakota digital sgi-5 interface, with respect to a racelogic vbox gps based data aquisition system, so I know the speedo is on the money. I have 275/40R17 Nitto 555Rs.
I assume your tire rolling radius is similar 811 revs/mile or so, but this could be an additional source of error if you have 285s or 315s, but they are all pretty close in terms of rolling radius.
The rpm data on my logs is a bit noisy, but the average rpm at 110 mph is 5500 rpm in 4th gear. Therefore:
110 mph/0.70 = 157 mph
130 mph/110 mph X 5500 rpm = 6500 rpm
You get the idea.