I am still pretty new with my c5. I have not done any major mods yet- and am told by new friends/owners to get an LS6 intake with a ported/polished TB.
my plea (question)s are

1. is this the best (economic and bolt on, not opening up the engine) MOD for the buck?
2. why LS6??? and what years are stock with ls6? (ie 2000-2004 or?) and why not FAST or an LS3 ..... or even ls7 (if it even fits)
3. what is porting a tb, just a hole or how, and where?)
4. what MM TB.... is best ? ( not planning on too many engine mods.) for a stock ls6 / and /or a fast brand?

I have a vararam just installed, and NOTHING else done. will be putting on a oil sending unit relocate kit when I do the intake also.

thanks for the help.

carlos

 

I've had my '98 C5 for about 1 1/2 years after owning a C4. I went through all the stuff you are wondering about. The LS6 manifold is an relatively economical way to make more power because it flows better than an LS1 and is a direct bolt on besides needing the coolant bypass hose and plug kit easily sourced from someone like GM Partshouse. I definitely noticed a difference even without a tune. There is usually good used LS6 manifolds on sale for around $350. There are several part numbers for LS6 manifolds. A quick search will give you those. FAST manifolds are great but are much more expensive. Ported throttle bodies in my opinion aren't worth the hassle. The opening in the LS6 manifold is 78mm. Having a throttle body with a bigger hole than that doesn't do any good. Your LS1 TB is 78mm and will work just fine with an LS6 manifold. Like I said, just my opinion and what I started out with. Oh, by the way, a good set of headers like XS Power longtubes is another great add on and should be one of the very first things you do. Putting more air in the motor won't do much good if you can't get it out. There are many helpful people on this forum and I have learned a great amount here.


Good Luck and have fun!

 

Thanks reply 1.

I am also told a little about the headers and will do that afterwards with more money and time. WHY do you not like a ported? does it make it bigger than the 78mm stock?, and even if i do find a good ported and polished 78 or 90, should I get it, just cause?

Thanks again.

 

Fast intake are a lot more money vs a ls6. Ls3 and 7 will not work on a set of ls1 heads.ls6 intake come on 01 to 04 vettes stock

 

1. Probably. Long Tube headers would be a close second.
2. It flows better than the LS1. LS7 and LS3 intakes will not fit on your LS1.
3. Porting and polishing the TB just means smoothing out the inside of the plate that air flows through. There are also spiral ported TBs available for sale from forum vendors. Google ported tb's and read some so you understand what you're looking into. Not worth it IMO for a stock motor but if you do it you'll probably notice a little better throttle response. Real HP gains are minimal...
4. Up to you but I'd stick with stock width on a non-modded motor.

Your approach to mods like this should really depend on your long term plans. If you are thinking of doing a heads/cam swap eventually then a ported tb might be worth it for you. You might also consider having your LS6 intake ported before installing it if you're going that route.

If you're planning on leaving the motor stock and doing bolt-on mods save your money on the porting and buy a tune instead. A full dyno tune would be best as it would free up some real horsepower and, in the hands of a competent tuner, will make it feel like a completely different car. Even a mail order tune is better than stock and can be had pretty cheap from ECS.

If you ever plan on doing LT headers then wait to do the tune until after you have them. You'll need a tune after installing those or you'll be running extremely rich. Also, a tune will help you get the most out of running your new LS6 intake.

People would be able to give you more solid advice as to the order and sense of your mods if we knew your long term power goals for the car.

 

The LS6intake is a great easy mod--usually worth an honest 12-14 RWHP--You also should check tour PCV system while you have the intake off---LS1's are notorious for sucking up oil into your manifold via the PCV system, With your old manifold OFF take a look inside of it with a flashlight--You may be shocked at how much oil is in there !! Not good---Most will while changing the intake ,install a LS6 intake valley--this helps reduce the amount of oil that gets into the manifold--however it take some effort and clearancing to get it to fit--It also re routes your PCV system--If you see on the forum there is a huge # of postings on this subject that include adding a "catch can" which is the ultimate fix--
As far as a ported TB---Yes it helps but not much HP wise but aids throttle response greatly-I would never attemp to do it yourself but have a pro do it--You do not need a larger TB though with stock cubes or a daily driver--it most always creates driveability issues

 

Picture time..

Yes,, the LS6 Intake Manifold is a good solid HP increase. Any 2001-2004 LS1 intake is the same style as an LS6 intake Its an OEM install.

You will need to deal with the coolant crossover pipe under the LS1 manifold. The little metal line will prevent the manifold from seating correctly. You can either convert to the 2001-2004 coolant cross over system OR remove some of the ribbing on the bottom of the manifold so that it fits correctly.

Here is the difference between the LS1 & LS2 (2001+) manifolds:

LS1 =



LS6 (2001+) =




STOCK LS1 TB =


Ported/Polished LS TB (78mm)

Shaner professional ported TB


Home ported quickie job =



Comparison between LS1/6 and LS2 TB =



Your stuck with a 78mm TB 'UNLESS" you have TPSI graph on a LS2 TB on your LS6 manifold ($350) or,,, install a FAST 90. Your TB is NOT a restriction at your HP Levels! PERIOD! Neither is the MAF!

Here is an example of the valve valley cover with the improved LS6 PCV system:






Get a set of XS Power Headers from SUPERMAN09 (outstanding budget LS Headers) install the LS6 style intake with the ported TB and get a good professional tune. You will need to buy a CROW BAR to pry the grin off your face.



BC

 

As usual, thank you Bill for the excellent information.

 

THANKS TO ALL that answered, especially my new schoolers, 'bill culree' and cdkcorvette7... for going the extra mile with pics and great detailed explanations, but all have helped and will now proceed. I appreciate the QUIK and awesome responses and cant thank you guys enough for helping.

AWSESOME friends here!!

keep cruisin'

REBELDE.....

 

Chriswtx has a ls6 intake for sale if you're going that route. He's in San Marcos. Not sure what he's looking to get for it but you can PM him if you're in the market.

 

thanks ill try to look up his address/info,....

 

Great job Bill !!!!!!!!!!

 

I switched from a ls1 manifold to a ls6 manifold when i had my old camaro. I paid 300 for the ls6 manifold and got 100 back after selling the ls1 so it was a pretty good deal, kept the stock throttle body, never re-tuned but I could definitely feel the difference in the seat of your pants dyno, and the car seemed to breath a lot better at the top end. I was originally looking for a fast but a fast 102 was too big for my basically stock engine and the fast 90/90 setup was way out of my price range at the time best $200 spent on that car.

 

THanks again everyone, and Torchred today....

I will be getting something, and heed the advise. especially on the headers, more in does need more out, makes perfect sense.

keep kruisin' and have FUn!!

 

I just installed the headers and x-pipe this weekend. I already had a b&b catback from before. I consider the headers/x-pipe my first real modd. I freakin love them. They change the whole sound and attitude of the car. I didn't even get a tune yet and I can tell a world of difference. Definately more than just the placebo effect that some mods have. My only regret is not doing LT and x-pipe sooner. Superman09 is a great vendor to deal with. Fast shiping and great communication. I am afraid I have now been bitten by the mod bug. Looking for the next step.

Have fun with it!