FAST LSXr 102 Nonsense

[Crazy Paul]

So when installing the LS3 version of the LSXr102 intake manifold and re-using the stock fuelrail on an L76 or LS3......you need to purchase injector height adapters if using the stock L76/LS3 injectors.
Granted.
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/G8%20Fuel%20System/cup2.jpg

Now the only purpose of this kit is to compensate for the extra height of the FAST 102 over the stock LS3 intake manifold. This extra height would not normally allow the stock LS3 fuel rail to extend low enough to allow the LS3 injectors to plug in top and bottom.
So we make up for that approx 1/2" shortfall by using the FAST #146025-KIT
Granted again.

So why would FAST recommend the 146025 height adapters be fitted below the injector where they will affect the spray pattern and port targetting? The injector tips will be raised 1/2" above the GM design height and additionally spraying through a much reduced bore size. The injectors normally spray into a 15/32" bore leading straight thru to the port. The lower bore of the FAST aluminium adapters must be somewhat smaller than that.

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/G8%20Fuel%20System/cup1.jpg

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/G8%20Fuel%20System/cup3.jpg

Unless I'm missing something, it would make much better sense to fit the height adapters on top of the injectors.....between the injector top and the fuelrail. Then you would not be messing with the spray pattern or injector tip height above the intake port.

[Crazy Paul]

The injectors normally spray into a 15/32" bore leading straight thru to the port. The lower bore of the FAST aluminium adapters must be somewhat smaller than that.

15/32" or about 11.9mm is the LS3 intake manifold injector bore straight thru to the intake port.
I dont have a FAST 146025 aluminium adapter here to measure but from looking at pics the adapter lower bore seems to be about 1/4" or 6.5mm ish

[norm8332]

are you sure they aren't supposed to be installed on the top to begin with? I agree they belong on top.

[Crazy Paul]

Arent the top of the injectors clipped in and the fast spacers don't have provisions for that?


Yes you're correct, the FAST adapters would need a groove on the male end and a clip on the female end if you were to try and install them above the injector. I suppose to keep manufacturing costs down they went the way they did.

[wreckwriter]

If one can afford that manifold I'd say a nice set of Aeromotive rails wouldn't hit the bank too hard and would eliminate this problem.

[Devilish34]

If one can afford that manifold I'd say a nice set of Aeromotive rails wouldn't hit the bank too hard and would eliminate this problem.

This

[Crazy Paul]

Current method used.
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/G8%20Fuel%20System/Injector.jpg
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/G8%20Fuel%20System/cup02.jpg


What I'm thinking would be a better design.
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/G8%20Fuel%20System/cup03.jpg
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/G8%20Fuel%20System/Injector.jpg

[DarkPhoenix]

I agree with your idea, makes much more sense than putting the adapters on the bottom.

[jimmytt6]

If one can afford that manifold I'd say a nice set of Aeromotive rails wouldn't hit the bank too hard and would eliminate this problem.

You wouldn't happen to have part #'s or any more specific info on these would you?
thanks
Jim

[jimmytt6]

http://aeromotiveinc.com/products-page/fuel-rails-systems/gm/14115-gm-ls3l76-fuel-rail-kit/

Is this ther aeromotive rails you are talking about?

[wreckwriter]

http://aeromotiveinc.com/products-page/fuel-rails-systems/gm/14115-gm-ls3l76-fuel-rail-kit/

Is this ther aeromotive rails you are talking about?

Yes, that's the ones I have on my car. assume they will fit the FAST manifold but research it first.

[GRRRR8]

I agree with Paul on this and it is the main reason I am switching out to the FAST fuel rails and braided lines before I re-dyno/tune the car.

Assembling it all on my workbench made it quite obvious how this could effect spray pattern etc.

My intake was almost $1400 ported/shipped. Fuel rails, lines fittings, gauge for a professional installation looks to be about $600. This is to snap on to the factory fuel line at the back of the intake. When I scrap all the factory fueltank, lines, EVAP for a cell, controller and balanced fuel system it will be considerably more.

[travis gore]

If one can afford that manifold I'd say a nice set of Aeromotive rails wouldn't hit the bank too hard and would eliminate this problem.
Tom do you have a picture of how the fuel line hooks into these? do you need to change the fuel line that comes from the firewall?

[Tweed1cg]

My dad had the LSXr intake installed and tuned by LMS, but had it removed because it just didn't seem to be running well. Could the adapters have been the problem? If the fuel rails would solve it, I would definitely get him those for Christmas so that he can get the intake put back on, it seems like there is more power to be had with it, and it just looks downright sexy!

[wreckwriter]

Travis, I'm out now so don't have the information. Do a search, pretty sure I did an installation thread when I put them on.

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[SS DAVE]

Tom do you have a picture of how the fuel line hooks into these? do you need to change the fuel line that comes from the firewall?

if you buy the fast fuel rail kit it comes with a russel fuel fitting that snap locks onto the factory fuel line at the fire wall,very neat and safe,if you get one of these manifolds get the fuel rail kit as well definately worth the dollars imop

[SS DAVE]

a few pics

[travis gore]

a few pics


if you buy the fast fuel rail kit it comes with a russel fuel fitting that snap locks onto the factory fuel line at the fire wall,very neat and safe,if you get one of these manifolds get the fuel rail kit as well definately worth the dollars imop

thanks for the info and pics. I am not planning on using a fast. I just don't like the look of the stock fuel rail.

[wreckwriter]

Here Travis:

http://forum.grrrr8.net/showthread.php?t=3673&highlight=aeromotive+fuel+rails

[travis gore]

Here Travis:

http://forum.grrrr8.net/showthread.php?t=3673&highlight=aeromotive+fuel+rails

Thanks Tom

[wreckwriter]

MGM, what throttle body?

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[wreckwriter]

Interesting. Thanks

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[GeorgeInNePa]

I agree with Paul on this and it is the main reason I am switching out to the FAST fuel rails and braided lines before I re-dyno/tune the car.

Assembling it all on my workbench made it quite obvious how this could effect spray pattern etc.

My intake was almost $1400 ported/shipped. Fuel rails, lines fittings, gauge for a professional installation looks to be about $600. This is to snap on to the factory fuel line at the back of the intake. When I scrap all the factory fueltank, lines, EVAP for a cell, controller and balanced fuel system it will be considerably more.

Don't forget extra shiney bolts!

[Greg@PacePerformance]

I am pretty sure you can switch to an OEM LS7 fuel rail and not have to use the spacers or aftermarket fuel rails, but I could be mistaken.

[Devilish34]

I am pretty sure you can switch to an OEM LS7 fuel rail and not have to use the spacers or aftermarket fuel rails, but I could be mistaken.

you should test it out and send your 2300 to me.... You still have my address I'm sure.....

[Greg@PacePerformance]

I have another G8 I could test on if needed, so no need to send it to you sorry.

[Devilish34]

aww shucks

[Patrick G]

Sorry I'm late to responding to this thread. I've successfully tuned a fair number of cars with these spacers and have not had any power or fuel delivery issues compared to cars running aftermarket fuel rails and no spacers.

I asked the question to the Comp Engineer responsible for the design of the FAST 102 LSXR intake and here was his response:

If you look at the injector pattern of the ls3/ls7 injectors, its not a plume. Its a pencil style injector. Ive tested with and without the spacers and saw ZERO difference. Ive run them on my truck before also.
We made some top mount spacers and tried them out. They cause an extra
place for the injector to pivot and I knew withing two minutes that we would be buying burned down corvttes with the top mounts. I still have them in storage.
If these guys want to run OEM rails and not the spacers, FAST offers drop in LS2 injectors in 34/46/57 lb/hr. OUr billet rails also are a good solution, but require custom fuel line plumbing.

Hope this helps. Patrick

[vx-355]

I have billet fuel rails and braided lines which are made by www.aseturbo.com.au and look great. You don't need spacers and run a standard size injector. U can see what I am talking about on their website, but you need to call/email them and tell them u need the kit to suit a FAST manifold.