LS1\2\6 Intake manifold swap 2.2 23 JAN
 

I thought id take some time to clarify the much needed much debated intake swap issue and to alleviate some confusion.

Lets start off with the first question of why do i need to swap my intake? Simply put the LS4 Intake Manifold is the absolute worst of the whole LS family, Which is why when any of the LS family intakes are swapped there are gains. i will cover TB/MAF upgrades in the next post.

This thread will show the power diffrences although this was done on a 6.0,our diffrences would still reflect what these tests show
--- http://www.ls1gto.com/forums/showthread.php?t=289456---

So what are your options?

You can opt to have your stock manifold ported out, The company who did a couple of members was fasterproms link here http://www.fasterproms.net/services.html

Moving on, from stock manifold porting we have the actual intake manifolds. These would be available from the following cars

LS1- available from 97-2000 Fbody cars
LS2 -2005-2006 GTO,05-06 VETTE
LS6-Available on 2001-2002 Fbody, 2004 GTO, 01-04 Vette, and 1st Gen CTSv

the 3 bolt truck intake manifolds from any 4.8,5.3, or 6.0 with more extensive work can made to work, same with the 4 bolt TBSS

F.A.S.T intakes can also work.

Lets break down the manifolds

pros /cons
1. The LS4-Its common knowledge that the LS4 by far is the worst car intake made, no need to discuss its already on your car.

LS1- This manfold will pick up some gains over the LS4 and anything help. Its noted for its curved underbelly and EGR port by the intake it has a 78mm 3 bolt throttle body bolt pattern.

LS6- One of the best flowing manifolds available in stock form, even with a 78mm inlet it still outperforms the LS2 stock for stock. This intake does not have a EGR, and has a flat underbelly, which will need sanding

Both of these intakes can follow the standard LS1/LS6 intake sticky here
https://ls1tech.com/forums/ls4-perfo...ap-sticky.html

http://www.grandprixforums.com/threads/24080-*HOW-TO*-LS6-Intake-Manifold-Swap-D-O-D ----Alternative install

at a glance for these intakes you will need:
Ev1-EV6 Injector harness adapters
Throttle body adapter/solution from will at overkill (Its also possible for LS2 90mm, adapters can be found on ebay 3-4bolt TB adapter)
preferably LS1\6 fuel rails and injectors
Your Oil pressure sensor housing must be modded to clear the neck of the intake just like the sticky says
modify alternator bracket to clear ls1/6 rails.
Make your MAP sensor mount whatever way you feel is best. There is no "best" way

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LS2 In standard form this intake even with a LS2 Throttle body (90mm)is still behind the LS6. However these are cost effective as most people do not want them due to minor issues that can resolved with some TLC. These can be ported and easily out flow a LS6 and comparable to a fast 90.
The above statement is not saying that you cant use a completeley stock LS2 intake, A stock one will work just fine. If youre looking to squeeze everylittle bit of performance out that manifold though it will need porting. you can do it youreself or have a reputable company like peak speed port it for you. http://www.corvetteforum.com/forums/...peed-shop.html
So what do you need to make it work?
-Throttle body either make a adapter or buy a LS2 which requires a pigtail as well.
Your stock Fuel rails and injectors will work just need spacers and two nuts in between the rail and fuel rail mount
a reworked valley cover
If you dont wana hack up your intake on the neck side then use the G8 valley cover. the oil passage does need working https://ls1tech.com/forums/ls4-perfo...ley-cover.html
(i opted to relocate the OPSU using this https://ls1tech.com/forums/ls4-perfo...installed.html)
Nothing else required to make that work beyond having fittings put in for brake booster and evap.


LS2 installs

https://ls1tech.com/forums/ls4-perfo...e-install.html
https://ls1tech.com/forums/ls4-perfo...s2-intake.html
https://ls1tech.com/forums/ls4-perfo...eping-dod.html

https://ls1tech.com/forums/ls4-performance-108/
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FAST Installs- These require a combination of both writeup procedures above. i wouldnt recomend these manifold though unless your cam/Head combo would benefit.


https://ls1tech.com/forums/ls4-perfo...y-install.html FAST 102

https://ls1tech.com/forums/ls4-perfo...dn-t-done.html FAST 92

Truck
There have been multiple successful swaps to the 3 bolt truck intake, The top of the manifold was shaved to help with hood clearance but not mandatory. These truck manifolds have really great flow potential, and for the DIY person these are a cheap hp/dollar gains to be had.

Links: https://ls1tech.com/forums/ls4-perfo...l#post19392458

Now that you are familiar on the intake or at least have some understanding, The next thing you need to handle is the rest of the intake tract.

Starting with throttle bodies

FAQ

1 can my stock throttle body work with XYZ intake?

YES, You simply need to make a adapter plate or link up with will from overkillmotorsports. Regardless though you will need to have a adapter no matter what.

2.Can i use the LS2/LS3 90mm throttle bodies?

Yes, These throttle bodies bolt right onto your LS2/FAST/or 4bolt Truck manifold with no adapter plate neccesary. But heres the catch for any 05-07 LS4 with a 8 pin Throttle body harness you will need to splice a 6 pin throttle body harness to be compatible. i provided a writeup here https://ls1tech.com/forums/ls4-perfo...b-pin-out.html but this is for 06, as mentioned you will want to confirm your wiring diagram before proceding. For 08 LS4's with the 6 pin its a plug and play, however it never hurts to confirm.

3.Can i use a ls1/6 Drive by wire throttle body?

Yes, one member here has been succeful but at this time i do not have a writeup to provide at the moment


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IMPORTANT PLEASE READ!!!

1.Be aware that you cannot use a NON-DOD Valley cover while you still have DOD cam and DOD lifters. Even if DOD is tuned off. you will collapse a DOD lifter.

2.You must have the car tuned to run a different throttle body I.E LS2/3/7 truck etc.... The car will go into reduced power mode so it is best to have everything at the time of install.

3. You must tune at the same time you install a MAF. The car will not run with a card maf upgrade on stock maf tables.

Changelog

23 JAN 2017
-Added Truck information at the bottom of post#1
-Bottom of post #2 Contains mandatory information on LS4 swapping information must read

25 MAY 2015

-Added LS2 Intake manifold information

10 AUG 2015

-Added truck intake manifold thread link into main post.

nice work.

got any info no the ls2 issues that need to be worked out to make them flow better?

ill put more info in that section this is rough draft so i need yalls input to help make it less confusing

do we have verification that the LS4>LS2 pinout for switching TB's works? This is something I want to look into after the car is up and running, if I can ill dyno before and after with my mods, see how much I pick up.

ty 91 I'm about to do swap in 2 weeks ill let u guys know how it goes

Well yea that's why I put verified in the title but if you're 07 and up I have not verified that

07 and up doesn't need to repin for a LS2 TB. Just needs a tune.

07 does, they still have a 8pin connector. 08 dosent they have 6 pins which plug directly into the TB

Ls6
 

Thank you for this!...hey 91parkave why do u say we should preferably use ls6 fuel rail and injectors? What's wrong with using our ls4 fuel rail and injectors

Check the thread I put under the sticky for ls1/ls6 the one on grandprixforums.net it explains what needs to be done. Which in my opinion is risking messing your rails up

need to use the extension hats if your gonna use the LS4 fuel rail and injectors, they are shortys

Extension
 

Thanks for the info guys...but one would think just getting some extensions for the rail and injectors would be easier and safer than cutting your alternator bracket...plus I would rather keep my stuff anyways don't feel like wasting money.

you have to cut the alternator bracket to allow the manifold to fit, doesnt have anything to do with the injectors, the reason you need the hats is the manifold is physically taller. You arent compromising anything cutting the alternator bracket either. I'm doing mine and ill post some pictures of it. Gotta pick up some cutting wheels big enough to cut through this massive chunk of steel though.

Is cutting the alternator bracket required for the LS2 intake manifold swap?

I didn't think it was.

Not sure if it has the same size on the back portion of the manifold. The piece that you cut off the bracket is redundant though. Some sort of shield for the connector, don't know what exactly its shielding against though. Makes accessing that last intake manifold bolt alot easier too.

That's weird, figured the wiring would all be the same since they use the same ECMs.

2007 is the bastard child haha

Well i am glad to see that the LS2 IM is going to be a little cheaper and easier to use for this swap. Although with having to have to runners on the LS2 IM ported, it may even out the cost - and still be a little cheaper than the LS6 IM, and having to get injector spacers, injector wiring adaptors, having to have the alternator bracket cut, ect...

But i am a little curious about having to use the two