LS6 Intake_Questions

[98ramairguy]

I found a LS6 Intake for sale near me on craigslist. What are the casting numbers on them so that I know Im gettting the right intake. Also are there any other parts I need for the swap to my 98 Trans am?

[tatertot91]

You'll have to delete your EGR system if you haven't done so already. Another thing about the LS1 intake is the steam tubes that run across the heads also run underneath the intake, for them to clear the LS6 intake you'll either have to swap for the LS6 style steam tubes or grind the bottom of the intake down to clear them.

You want to see the part #12561184 or #12573572

[98ramairguy]

Do you know the part number for the LS6 coolant lines?

If I delete the EGR system will I have the check engine light on?

[tatertot91]

Quick search found this number for the crossover (12602544) and you also need 2 plugs for the rear part number 12602540. Removing egr will trigger the service engine light

[98ramairguy]

So a tune would be neccessary to get rid of it.

[tatertot91]

Correct, also forgot to add you need a blockoff plate if you remove egr. Slp does make an ls6 intake with the egr provision but its over 650 iirc

[98ramairguy]

I wish I didn't buy headers with the EGR fitting in them. It will look goofy with the tubes sticking up and them blocked off. Removing the EGR would include getting rid of the whole Secondary air injection pump system as well wouldn't it?

[tatertot91]

The air system is in no way connected to the egr system but if you're going to remove one then there really isn't much sense in keeping the other. Does your state gave emissions testing?

[98ramairguy]

One more question. If I get a LS6 intake does a 90mm throttle body work with it? Am I better off getting a 90mm intake over the LS6? Whats the best bang for my buck?

[tatertot91]

90mm wouldn't work with the ls6, you would need a fast or some other intake that is compatible with a 4 bolt throttle body. With the ls6 intake you would be best with a ported stock throttle body. As for the best bang for your buck, really depends on your plans for the car. For a mostly stock bolt on car you can't beat the ls6, you really need at least a cam to get any solid numbers from the larger intakes.

[98ramairguy]

My plans are to eventually get a cam and some valve work. But beyond that I don't see myself buying heads for a long time. The LS6 manifold seems like the way to go. I was also looking at the Holley which has the EGR provision. The difference is only about $100, but my question is if there is any difference in power gains from the two? Ill save the $100 easy if I don't have to get the EGR tuned out of my computer.

[tatertot91]

There's always an argument behind this but I personally prefer the LS6 for it's plastic design, makes it less prone to heat soak. Either should net you similar gains so go with whichever one you prefer. If maintaining your EGR is a big concern you might be better off with the holley but if you can get away without emmisions i'd recommend deleting it and getting it all tuned out later.

[98ramairguy]

Is there any advantage to getting rid of the EGR besides less clutter under the hood. In New York if a SES light is on it won't pass inspection. By heat soak do you mean the manifold getting warm and having more warm air entering the engine rather than cold?

[transamtom]

You should get a tune as the LS6 intake needs a little less timing and a bit more fuel.

Frost can hook you up with a good mail order bolt on tune.

Plus he can delete your EGR and Air systems so you have no CEL's on.

My Frost tuned 99 TA passed the new OBD2 test here.

[tatertot91]

EGR (exhaust gas recirculation) does just that, basically its a valve with piping that circulates hot exhaust fumes back into your intake manifold. Good for emmisions, bad for power. And yes exactly what i mean by heat soak.

[98ramairguy]

What does a tune to eliminate those things cost from frost? I could get the Holley keep the EGR for now and then when I get the cam and valve work with a tune have them tune those out and put the blocker on the manifold. That may be the route I take, Am I going to notice any difference in the SOTP with a new manifold? They claim 25 hp but I know those numbers are exaggerated.

Also If I get rid of the EGR in theory wouldn't that eliminate a lot of the heat soak? I like the polished Holley manifold because it looks nice and it gives me options

[98ramairguy]

There are so many conflicting points of view, from everything I read Im leaning toward an LS6 manifold. I think it would be a good idea to get it ported and also get my stock TB ported. I think that that will give me the best HP gains with the least cost and not have to deal with possible heat soak

Opinions??

[transamtom]

There are so many conflicting points of view, from everything I read Im leaning toward an LS6 manifold. I think it would be a good idea to get it ported and also get my stock TB ported. I think that that will give me the best HP gains with the least cost and not have to deal with possible heat soak

Opinions??

No need to port the LS6 intake,if your going to go through that then you might as well just spend the extra $$$ and get a Fast 92.

The whole idea behind the LS6 swap is 10-15hp for less than $500.00 you should do 2 new knock sensors and a harness while your in there also the OPSU.

[98ramairguy]

OK Thanks that's what Im going to do. LS6 manifold get my Tb ported and be done with it. Any idea what the part numbers are for the OPSU and the knock sensors? Will the other sensors from my intake transfer over to the LS6 one?

[transamtom]

OK Thanks that's what Im going to do. LS6 manifold get my Tb ported and be done with it. Any idea what the part numbers are for the OPSU and the knock sensors? Will the other sensors from my intake transfer over to the LS6 one?

There is one other sensor the MAP on the back and yes it fits,your fuel rail is held by 4 bolts just wiggle and pull on the rail to free the injectors and lay it off to the side.

Any GM dealer will have the OPSU, KS's and harness.

Get yourself some new Felpro intake gaskets a can or 2 of brake cleaner and 8 old socks or rags.

There will be a mess of oil/gunk when you pull the old intake plug your ports and get cleaning