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LS1 Engine mods for road racing

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Old 11-14-2006 | 06:26 PM
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Default LS1 Engine mods for road racing

I have swapped a LS1 into my RX-7. I plan on doing track days and high speed autocross.

What do I need to do to the motor to make it bullet proof. The motor is stock. I am running NPG. The mods I was thinking of are:
160 degree thermostat?
Stock LS6 or ported oil pump (which one)?
Upgraded pushrods and spring?
Old 11-14-2006 | 11:07 PM
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what year LS1 is it? Also I would consider an oil cooler and an oil accumulator.
Old 11-15-2006 | 08:23 AM
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It is a '00 ls1.


Originally Posted by DONAIMIAN
what year LS1 is it? Also I would consider an oil cooler and an oil accumulator.
Old 11-15-2006 | 09:36 AM
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Originally Posted by Wickedone
What do I need to do to the motor to make it bullet proof. The motor is stock.
Keep it cool ... whatever it takes, keep the motor cool.

Keep it lubed. I ran a ported pump, but that was because "LS6" was a twinkle in some GM engineer's eye at the time. So, who knows which is better.

Keep it full. I ran 7qts of oil in my 98 Trans AM and a stock pan. LS1s have issues with oil starving on long, high G left handers.

Replace springs with good doubles, but leave the stock push rods. My philosophy is that it's easier and less expensive to replace bent push rods than bent valves.

Rod bolts. Some version of LSx motors are prone to rod bolt stretch when punished for long periods of time.

Remember ... you don't have to rev a road race motor to the moon. LSx motors make great torque at 35-5500. And in a stripped RX7 weighing in at a whopping 2500lbs, you should be able to make many Porsche or Z06 wish for more right pedal.

Weight, torque and momentum are the keys to low lap times.
Old 11-15-2006 | 10:30 AM
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Originally Posted by mitchntx
Replace springs with good doubles, but leave the stock push rods. My philosophy is that it's easier and less expensive to replace bent push rods than bent valves.
So it'd be better even on a stock cam'd car to have double springs? I was asking the internal section and they told me to do singles with tit retainers and hardened pushrods on my stock cam'd car. I am doing road racing just like the thread starter.

Anyways i've been road racing twice with my ls1 rx7 with only the issue of getting hot (not overheating). Make sure you have your cooling system in good shape. Putting the undertray on helps alot too. Last time I was out I was seeing about 210-220 water temps and about 220-225 oil temps. I have a grannys radiator with a custom shrouded Taurus fan on "high" setting. Rev the car to about 5.5k in the corners, and on the straights hit 6k. Even with a stock ls1 (01 motor) and weighing 2680 pounds, nobody touched me on the straights. I was hitting about ~145 on the back straight at buttonwillow for reference


Running 7 quarts is mandatory for sure though! The last time I was out there a vette was coming out of lost hill and he starved his motor
Old 11-15-2006 | 10:45 AM
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Originally Posted by andrewdruiz
So it'd be better even on a stock cam'd car to have double springs? I was asking the internal section and they told me to do singles with tit retainers and hardened pushrods on my stock cam'd car. I am doing road racing just like the thread starter.
And most folks on here are drag racers and don't do a lot of compression braking. They also run their motors hard for 10-12 seconds, not 30 minutes. And they rev these bullets WAY up there. Like you said, 5500 is twist enough.

With a stock cam and a double spring, if you bust an outer spring, the one most likely to fail, the inner has enough tension on it to keep the valve off the piston.

And a stock push rod will give as long as a piston to valve "kiss" is minimal. Chances are that the damge will be greater if a hardened push rod doesn't bend. I equate the stock push rod to that of a fuse in an electrical circuit.

But, everyone has an opinion. I personally like to drive my car onto the trailer after a weekend's running.
Old 11-15-2006 | 01:25 PM
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Thanks for the heads up on the 7 quarts, I didn’t know this. I am in the process of building aluminum shrouding around the entire front of the radiator. I am running the stock Rx7 fans on Med or High. Any reason not to run the 160 Degree thermostat? or what about drilling hole in the periphery of the stock one? I did this on the rotary and it helped a lot with flow.

So I think I am just going to replace the springs, if I bend a pushrod, that is cheap and easy to replace, Valves… not so much.

Would there be any reason NOT to run a ls6 Ported vs. stock ls6? I would rather go overboard than save the extra $100.

Where is the easiest place to put the probe for the oil temp gauge?

Thanks for everyone’s help.

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Old 11-15-2006 | 01:59 PM
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Oil temp: I bought a metric plug (25x1.75 I think) at O'reilly's, drilled the center out and tapped it to 1/8" pipe. I installed the temp sensor in the plug and put the plug where the oil level sensor was in the pan. I then jumpered the oil level sensor plug on the harness so that I wouldn't get a light on the dash. I don't think the ECM cared, but couldn't confirm it.

Water temp: 160* stat should be fine.

Can't tell you much on the pump.
Old 11-15-2006 | 04:40 PM
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Originally Posted by mitchntx
And most folks on here are drag racers and don't do a lot of compression braking. They also run their motors hard for 10-12 seconds, not 30 minutes. And they rev these bullets WAY up there. Like you said, 5500 is twist enough.

With a stock cam and a double spring, if you bust an outer spring, the one most likely to fail, the inner has enough tension on it to keep the valve off the piston.

And a stock push rod will give as long as a piston to valve "kiss" is minimal. Chances are that the damge will be greater if a hardened push rod doesn't bend. I equate the stock push rod to that of a fuse in an electrical circuit.

But, everyone has an opinion. I personally like to drive my car onto the trailer after a weekend's running.
You make a great point.
Old 11-15-2006 | 04:57 PM
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Originally Posted by mitchntx
Keep it full. I ran 7qts of oil in my 98 Trans AM and a stock pan. LS1s have issues with oil starving on long, high G left handers.

So what about if you drive the car to and from the autox/track? Is it safe to fill with 6, or 7qts and keep it there, or should it be drained after every race? I have the usual bolt ons w/headers, stock susp. (for now) and plan on having slicks for next years autoxing. It's not a daily driver, weekend/nice weather/autox only. Would it be safe to keep it at 6 or 7 qts?
Old 11-15-2006 | 05:48 PM
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I ran 7 all the time ...

Here's some discussion on oil levels in the pan ...
http://www.frrax.com/rrforum/index.php?showtopic=1227
Old 11-15-2006 | 06:03 PM
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This may seem out of place, but what year LS1 is it? If it was from a 1999 or lower then I would seriously invest in a power steering cooler. I put one in mine. Also, to cool the engine I run Redline Water Wetter, 1 gallon of Dexcool, and the rest is water. I have a 160 thermostat and set one fan to turn on at 185 and then both turn on at 195.
Old 11-16-2006 | 08:14 AM
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It is a 2000 motor, why 99 or lower? Was the pump different?


Originally Posted by Ragingwolf51
This may seem out of place, but what year LS1 is it? If it was from a 1999 or lower then I would seriously invest in a power steering cooler. I put one in mine. Also, to cool the engine I run Redline Water Wetter, 1 gallon of Dexcool, and the rest is water. I have a 160 thermostat and set one fan to turn on at 185 and then both turn on at 195.
Old 11-16-2006 | 12:44 PM
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Originally Posted by Wickedone
It is a 2000 motor, why 99 or lower? Was the pump different?
He might be assuming that all of the 2000s and up came stock with the p.s. cooler. They did not. I have a 2000 and I had to order it as a stand alone option. Besides, if you're doing serious track work you'll want a REAL p.s. cooler (Mocal, Fluidyne, etc.) and Redline p.s. fluid. (If you're really hardcore, maybe even the Turn One pump!)

Last edited by dailydriver; 11-16-2006 at 12:49 PM.
Old 11-16-2006 | 04:07 PM
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Originally Posted by mitchntx
I ran 7 all the time ...
So you mean you run 7qts every day, regardless of autox or track runs?
Old 11-16-2006 | 05:22 PM
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Originally Posted by EchoMirage
So you mean you run 7qts every day, regardless of autox or track runs?
The ONLY time my LS1 car had less than 7 qts was when I was in the midst of changing the oil
Old 11-17-2006 | 04:17 PM
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Does that have any adverse effects on the oil pump? Were you running a stock or aftermarket pump?
Old 11-26-2006 | 01:42 PM
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Originally Posted by Wickedone
I have swapped a LS1 into my RX-7. I plan on doing track days and high speed autocross.

What do I need to do to the motor to make it bullet proof. The motor is stock. I am running NPG. The mods I was thinking of are:
160 degree thermostat?
Stock LS6 or ported oil pump (which one)?
Upgraded pushrods and spring?
Bullet proof, no such thing! Weak links as other stated LS1 pump(ported/shimed/duburred/springed a minumum) belt tensioner and make sure that crank is keyed/pined! I would just fork over the extra $$ and buy KATEC pump and tensioner. If you are using the C5 oil pan, for sure 1 qt over(also think about high weight oil)

If you are going with slicks or r compounds, the oiling issue(especially on lft hander sweepers i.e. Button Willow 13ccw) is accurate and only way I've found to combat this is (excluding EGR crap) extended/baffled breathers/catch can or aftermarket taller valve covers.

Change fluids before and after 2 day events and you should be fine!

Good luck...



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