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Old 27th March 2010, 10:13 PM  
blueovalz's Avatar
Skinny Man
United States
Join Date: Aug 2008
Location: Arkansas
GT40: An orange car
Posts: 2,126
Progress on a Poor Man's LS1 ITB set-up

Economy price for an LS1 ITB intake manifold; $1400
Economy price for a set of 8 ITBs for a V-8; $1800

No horns, linkage, injectors, control, so that’s another who knows how much.

Total to just get started; $3200

So here’s my plan:

Edelbrock Pro-Flow XT LS1 intake manifold; $425

Chrysler LHS throttle bodies (8 total), salvage price; $160

Misc pieces to make this work: $125

Total to be in about the same position without the debt; $710

Plus it will be too cool if this really works (that’s priceless).

The intake will have the top cut off to expose each of the eight runners. The lower portion of the intake has all the injector bungs so that eliminates any complications with aftermarket injector set-ups. Thus all I need is a set of throttle bodies to place over the open runners (the runners will be modified to reduce the angle between the ITB centerline, and the centerline of the runner. My plan is to weld a mounting plate onto the top of the open runners, and then bolt an adapter plate to the mounting plate. This will allow me to use a variety of Weber or ITB induction set-ups by changing only the adapter plate.

The ITBs. The Chrysler LHS 3.5L motor has a unique set-up for their throttle bodies. This engine uses two Holley 48mm throttle bodies in which one is attached to the throttle cable, and the other (on the opposite side of the intake connected by a torque tube) houses the TP sensor. For a factory TB, these pieces are surprisingly simple, and is lacking the usual crap that is attached to a factory part. So I purchased a bunch of these to experiment with to see what could be done with them.

The adapter plate will make the transition between a round ITB exit, and the semi-rectangular intake runner. I placed a rigid .390” rod (10 mm was too large) through all the bearings to align the TBs perfectly, spaced them to match the runner centerlines, clamped them down, and then used the TB mounting holes as a guide to drill the mounting holes into the adapter plate.

Then I drilled and tapped the holes for M8 studs (used the Chrysler studs because they’ve got a neat pilot shoulder to index the TB.

Then mount the ITBs, scribe out a circle on the plate for the exit hole

Rinse and repeat for the other side. Don’t know if this will really work, but cannot find a reason why it shouldn’t, and I’m having a ball so far! Once I get it all together, I'll clean up the plate to remove excess bulk, lighten it up, and make 'er pretty!

PS, sorry for all the spaces. The preview shows none at all, but the post shows otherwise.

Mirage photo-documentation

Attached Thumbnails
LSx - Weber Intake Manifold-100_5297-jpg   LSx - Weber Intake Manifold-100_5302-jpg   LSx - Weber Intake Manifold-100_5299-jpg   LSx - Weber Intake Manifold-100_5303-jpg   LSx - Weber Intake Manifold-100_5283-jpg  

LSx - Weber Intake Manifold-100_5285-jpg   LSx - Weber Intake Manifold-100_5288-jpg   LSx - Weber Intake Manifold-100_5286-jpg   LSx - Weber Intake Manifold-100_5291-jpg   LSx - Weber Intake Manifold-100_5292-jpg  


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Last edited by blueovalz; 27th March 2010 at 10:50 PM.
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