ricardo.benin

Hi I have a 1994 mazda rx7 that I am going to swap to a ls1 and I wanted to do a turbo ls1. So my question is what is the engines max safe power limit on a stock bottom end. Btw I plan to run 317 heads as well as a mild cam, from what I have read I believe the older z06 cam will work good for a turbo ls1.
Any advise would be greatly appreciated.
Thanks
Richard

TurboF-body

Unless you have a ls1 just laying around, I would get a 5.3 or 6.0. You can pick these up cheaper than an ls1 and you will get better power gains out of these engines. Both of these engines run an iron block and a lower compression meaning you can run more boost while putting less strain on your engine. If you do go with a 5.3 or 6.0, you will be able to spend more money on a better turbo. Your best bet is to find a cheap lq4 and add an ls9 or older z06 cam, ls6 or ls2 intake, valve springs, and a 76mm turbo. That should make plenty of power. A 5.3 will also make great power but you won't make quite as much as a 6.0.

Hope that helps

ricardo.benin

Hi thanks for the quick reply the problem is I can not run an iron block as that will screw up my 50/50 weight distribution so I have to run an aluminum block. My friend has a ls1 block for $200 in really nice shape so that is why I was thinking of using an ls1. Is 600hp achievable.

JoeNova

Haha. This gets asked so often I'm starting to think people are trolling. scroll down like 5 posts before yours.

JoeNova

Then get an aluminum 5.3. Better heads than the ls1 and more meat between cylinders.

Btw, the difference is about 60 lbs between an iron block and ls1 block. You can offset that easily. Your car doesn't have to be 50/50 to perform very well.

ricardo.benin

So the 5.3 is called a lq4, how strong is the bottom end on these blocks and what power can I make on the stock bottom end. Btw the big reason for the idea of using the ls1 is there is alot of info on swapping ls1 into rx7 as well as wirring info.
Thanks

TurboF-body

the 5.3 is not an lq4. The lq4 is a 6.0. The 6.0 will weigh more than the 5.3 and the ls1 will make more power. Any swap that is for an ls1 will work for a 6.0 or 5.3. The 6.0 and 5.3 have both been in the 700-800whp range on stock bottom end. most people back down on the boost though so their motor lasts longer. The reason you wouldn't want to go with a ls1 is because of the compression. Yes the 5.3 and 6.0 weigh more than the ls1, but in order to make a boosted ls1 600whp+, your gonna have to run 10psi plus. And once you get above 8 psi your gonna have to start saving money for when your ls1 blows up.

ricardo.benin

Hi thanks for all the info so on an ls1 is it the pistons or rods that normally go out.
Thanks

JoeNova

05(ish) brought updated rods/pistons in all of the LS motors. All LS1s had the older style rods which are much weaker. There are still guys on this forum making 800 whp with the older style rods.

If you want a strong stock bottom end, its going to have to be a gen 4 motor or one of the gen 3 motors that switched rods/pistons early. Yes, you can swap internals into an older block.

Rods break first from too much power/torque, pistons break from heat/detonation.