Superram, Mini ram with stock cam
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Superram, Mini ram with stock cam
I have an 87 l98 with a supercharger running 6psi of boost.
My dyno curve shows 290 hp at about 4000 rpm's and maintains that power to about 4800rpm's. It then falls to 255 hp at 5500 rpm's.
Max power at 4000 rpm's is terrible.
Is my power curve maxing at 4000 due to the factory intake or factory cam?
I feel the limit is the intake and was thinking of switching to a single plane intake or superram.
Has anyone run the stock l98 cam, with a superram, mini ram, or single plane intake? What did the dyno curve look like? (It doesn't have to be in a supercharged application, although that would be nice).
My dyno curve shows 290 hp at about 4000 rpm's and maintains that power to about 4800rpm's. It then falls to 255 hp at 5500 rpm's.
Max power at 4000 rpm's is terrible.
Is my power curve maxing at 4000 due to the factory intake or factory cam?
I feel the limit is the intake and was thinking of switching to a single plane intake or superram.
Has anyone run the stock l98 cam, with a superram, mini ram, or single plane intake? What did the dyno curve look like? (It doesn't have to be in a supercharged application, although that would be nice).
Race Director
Joined: Feb 1999
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From: Indianapolis IN
A SC application would be better served with a Miniram or SP,
I just swapped a guy my Miniram for his Superram that he took off his 355 w/SC making 600+ HP. The Superram was his restriction.
I just swapped a guy my Miniram for his Superram that he took off his 355 w/SC making 600+ HP. The Superram was his restriction.
Instructor
Joined: Aug 2004
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290 hp sounds a little low. My 91 made 343 hp at 5500 rpm and 6 psi. It was a stock engine that I added a Carroll supercharing kit to, stock intake.
In the beginning I had some problems though. My stock catalytic converter was bad, I replaced it and it resulted in a 33 hp gain. I added MSD 6 AL and that was another 9 hp.
Have you connected a scanner? Are you sure it is not running lean or some other problem?
In the beginning I had some problems though. My stock catalytic converter was bad, I replaced it and it resulted in a 33 hp gain. I added MSD 6 AL and that was another 9 hp.
Have you connected a scanner? Are you sure it is not running lean or some other problem?
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This was tested on a dyno and the fuel mix looked good.
Without the supercharger it made peak of about 210hp.
That is a 38% increase.
Going to 343hp from 210hp is a 63% increase. Never going to see that with 6psi of boost. Would need at least 9psi.
What did you have without the supercharger?
Unless you are talking at the motor, my measurements were taken at the wheels.
343hp at the motor would be 275hp at the wheels with a 20% drivetrain loss.
Without the supercharger it made peak of about 210hp.
That is a 38% increase.
Going to 343hp from 210hp is a 63% increase. Never going to see that with 6psi of boost. Would need at least 9psi.
What did you have without the supercharger?
Unless you are talking at the motor, my measurements were taken at the wheels.
343hp at the motor would be 275hp at the wheels with a 20% drivetrain loss.
Instructor
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Going to 343hp from 210hp is a 63% increase. Never going to see that with 6psi of boost. Would need at least 9psi.
The stock L98 will have its peak power at about 4000 rpm but the supercharged L98 will peak a little above 5000 rpm. The data sheet for my kit specifies 350 hp at 5250 rpm and 6 psi.
Like I said, my combination first produced 301 hp. Eventually I found the problems and after fixing it I reached 343 hp. I think 290 hp at 4000 rpm is not so bad but your engine should increase power up to about 5000 rpm... at least that is what I expected when comparing to my old setup. I'm sorry I never ran my stock on the dyno.
What mod do you have? Headers? Exhaust system? etc...
Hope this helps and good luck!
Le Mans Master
Joined: Jan 2003
Posts: 8,596
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From: Portland Oregon
Originally Posted by QuickGlass
This was tested on a dyno and the fuel mix looked good.
Without the supercharger it made peak of about 210hp.
That is a 38% increase.
Going to 343hp from 210hp is a 63% increase. Never going to see that with 6psi of boost. Would need at least 9psi.
What did you have without the supercharger?
Unless you are talking at the motor, my measurements were taken at the wheels.
343hp at the motor would be 275hp at the wheels with a 20% drivetrain loss.
Without the supercharger it made peak of about 210hp.
That is a 38% increase.
Going to 343hp from 210hp is a 63% increase. Never going to see that with 6psi of boost. Would need at least 9psi.
What did you have without the supercharger?
Unless you are talking at the motor, my measurements were taken at the wheels.
343hp at the motor would be 275hp at the wheels with a 20% drivetrain loss.
Did you have a boost gauge connected to the engine? Your numbers seems a little low to me. If the boost drops off you will loose power, which would usually mean that the belt is slipping.
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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Its your intake, not the cam. TPI kills the power up high.
With a SC, I'd probably go with the MR. SC will give the low end and the MR flows well enough up high so that it wont die off.
With a SC, I'd probably go with the MR. SC will give the low end and the MR flows well enough up high so that it wont die off.
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Thread Starter
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Vader86:
I also think it's the intake. But I may put in a mild cam at the same time.
Tjwong and Blower91
My test was run with a boost gauge showing 6psi at 5000 rpm.
The factory dyno curve falls right off down to 160hp at 5500 rpm.
With the supercharger I making 255hp that is a 59% gain.
I don't see how you can get higher horsepower when the stock horse is so low with the factory tpi intake.
Maybe my stock horsepower is just really low.
I am running no precats, a high flow main cat, and flowmaster catback.
Everything else is stock.
Do you have a before and after dyno curve?
Maybe your horsepower is much higher than mine without the supercharger.
I also think it's the intake. But I may put in a mild cam at the same time.
Tjwong and Blower91
My test was run with a boost gauge showing 6psi at 5000 rpm.
The factory dyno curve falls right off down to 160hp at 5500 rpm.
With the supercharger I making 255hp that is a 59% gain.
I don't see how you can get higher horsepower when the stock horse is so low with the factory tpi intake.
Maybe my stock horsepower is just really low.
I am running no precats, a high flow main cat, and flowmaster catback.
Everything else is stock.
Do you have a before and after dyno curve?
Maybe your horsepower is much higher than mine without the supercharger.
Instructor
Joined: Dec 2004
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I would say its both your intake and cam. While your intake is limiting your higher RPM potential, the cam is a limiting factor in your overall powerband. A more aggresive cam (as they were fairly mild stock) would certainly help you in all aspects. If your replacing the intake manifold why not go a few extra steps and do the cam as well. You wont be sorry 
.
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Instructor
Joined: Aug 2004
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I'm afraid I don't have a "before supercharging" dyno curve but I'm sure it would have made more than 210 hp, my guess is 260-270 hp at about 4000 rpm.
The 38% increase (210 -> 290) seems normal to me when you add the blower. Perhaps you run less spark advance than I do. Do you have much knock retard at WOT? Do you have any info on your EPROM?
The 38% increase (210 -> 290) seems normal to me when you add the blower. Perhaps you run less spark advance than I do. Do you have much knock retard at WOT? Do you have any info on your EPROM?