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How to decrease the power in a LS1

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Old 03-27-2011, 12:19 PM
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Originally Posted by futureuser
Are they are actually going to measure the horsepower and is it just one time?

Simply adjust or limit the movement of the throttle cable so that it only opens the throttle body part way.
TPS would show it being part-throttle. A restrictor plate would be much more effective.

You could build it up for torque instead of power and only rev it to 4k as others have said. That motor should last a million years only turning 4k.
Old 03-27-2011, 12:30 PM
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Originally Posted by mramay
This!
I've heard that a "valet key" option is available with LS1Edit but not with HPtuners.

I also want a "low horsepower" option since I don't want to give my wife or the casino valets here in Vegas a 500HP car. I need to do some more research to verify but I'm been told that a switch (key activated or toggle switch) can change the tune to a 200HP or so variant.
my viper alarm has this, it just limits the revs.
Old 03-27-2011, 02:01 PM
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Here's what you do...

Restrict the intake.. build a simple plate behind the throttle body with only a 40mm or so hole. Like a throttle body spacer, but tapered down.. You can easily remove it once it's inspected. It won't run poorly, it'll just lack power. (the MAF will still read airflow and compensate for it with the fuel..

Have a sponsor create a tune for you.. Pin the connector in the PCM for valet mode, install a toggle switch somewhere, and have one tune that lacks a serious amount of spark timing. I wouldn't tell your inspector person about this, just say it's detuned. They won't make any connection between a random toggle switch and the output of the engine. The second tune can have a rev limiter as well, make it redline at 4000 rpm and with that intake restriction, you may be within your power range.. if not, you can always use a 5.3 cam (designed for torque), and swap it back later.
Old 03-27-2011, 02:08 PM
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Originally Posted by Jimbo1367
Just limit the throttle/gas pedal.
aggreed buy an aftermarket throttle body and and adjust the screw that hits the bump stop on there to hit it as it barely opens


or toss in a 5.0
Old 03-27-2011, 04:05 PM
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Smile

For the first, I never gona swap the Jeep.

Thanks for good and better solutions here, 67RSCamaroVette probably got some of the best solutions. Nice to have someone to get tips from, thats means all of you.
Becouse of the silly customs/tax rules over her, the LS1 engine isnt verry common at all, rare is the right word. beautiful engine dow.

Close to night here now, good night for now

AR
Old 03-27-2011, 04:48 PM
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My problem is a little different - I'm looking for a switch that I can flip before I hand the car over to the valet. It isn't cool to get out and raise the hood at that time. :-)
Old 03-28-2011, 10:10 AM
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After you get it approved are you gonna go back to full power? Cant you just retard timing, thats how the computers limit power for traction control.
Old 03-28-2011, 10:17 AM
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The restrictor palte isn't a bad idea, what about putting an electric cutout before the throttle body? Close it like 50% when you have to do the test, then you can open it back up with a toggle switch. Never have to even shut the car off.
Old 03-28-2011, 10:26 AM
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Seem that a Restrictor plate and lowering the PCM's Rev Limiter would be the only safe way to do this...maybe tweeking the Fuel tables a bit (would not go to far, lean condition is not good).

Another items is the Spark advance, maybe taking out some and running a lower grade of fuel.
Old 03-28-2011, 12:14 PM
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Talk to FROST about his dual tune PCMs. See if he came tune it to be nice and slow on one tune and you can be back to a good tune with the flip of a switch
Old 03-28-2011, 12:19 PM
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They only check hp or torque also? Setting the limiter way low would limit horsepower. Or pulling gobs of timing out.
Old 03-28-2011, 12:36 PM
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Originally Posted by eviltwin_1987
talk to frost about his dual tune pcms. See if he came tune it to be nice and slow on one tune and you can be back to a good tune with the flip of a switch
this!
Old 03-28-2011, 01:57 PM
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I'd sell the jeep and look into moving somewhere else.
Old 03-28-2011, 02:25 PM
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install msd 2step launch control, have it engaged with a switch, set rev limit to 2.5k.
Old 03-28-2011, 04:28 PM
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Go with an aluminum 5.3.... Less horsepower, similar weight to the 4.0.
Old 03-28-2011, 05:52 PM
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Originally Posted by RATBOX
I'd sell the jeep and look into moving somewhere else.

Definatley move out of a country that wont allow you to swap ****. Then again CA has some retarded hippy laws too so we're a little better.
Old 03-28-2011, 06:47 PM
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As suggested, the best way to limit HP is with a rev limiter. I think a dual mode flash sounds like the most elegant solution. Remember, HP = (Torque x RPM)/5252

Andrew
Old 03-28-2011, 09:09 PM
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Throw a turbo at the 4 banger and get that tested, then when you swap to the LS the difference will be closer to that majic 10-15% mark.
Old 03-30-2011, 03:45 AM
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Originally Posted by Meierznutz
Throw a turbo at the 4 banger and get that tested, then when you swap to the LS the difference will be closer to that majic 10-15% mark.
well, it isnt that easy. The authorities only look at the hp in the Certificates of Title or what the main Jeep Importer tells about max hp.
Old 03-30-2011, 03:49 AM
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Originally Posted by usmcz28
Definatley move out of a country that wont allow you to swap ****. Then again CA has some retarded hippy laws too so we're a little better.

Here I come

Have heard about CA and the strikt rules there, we localy curse CA when we got car imported from CA over here.

AR


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