Vettegineer

I'm buying parts for my LS3 retrofit--and I have (at least) two questions that I can't figure out. I'm hoping some of you will tell me what you have done!

First, the LS3 intake is often shown with a bit of a stubbed off air filter at the intake. Even my L48 version reached out over the radiator for its meager 200 hp. I've seen guys make an immediate turn and run across the engine bay so the MAF has a straight-away, and I've seen some guys Y it out and run to both sides. I've even seen one picture where someone dropped the intake route downward, passed to the side of the radiator, and got a cone out front. I haven't seen an off-the-shelf solution. What are people doing lately? Seems like it matters where you get sufficient cool air for 480 hp.

I've read the sticky on LS swaps, and several books on the subject, but I've yet to get a feel for the optimal position of the LS3 corvette accessory kit version relative to "stock" location. I don't have a rack in yet, but intend to, and I'd really like the C4 front transverse springs in the front (someday,) and I need to fit headers in there--1/2" forward seems most people's guess. What have you guys done--there should be a best position for a c3 Vette!

Since I'm asking--one further question--I have quote for Melrose headers--but not too many headers fit for LS3 and C3 Vettes (or at least advertise that way.). Anyone found a Kooks set that fits? What are you using lately?

Thanks! Les

carriljc

The guy on this delorean states that it is.

http://ls1delorean.blogspot.com/

If it is, then you can just point it at the cowl and use cowl induction. May simplify things. You may want to look into that.

I remember reading something about this when I was putting the Ram Jet 350 in my 68......but it isn't reversible on the Ram Jet.
I ended up using a L88 hood and ducted some cowl air via that. You can see some pics under my corvette photos off to the left <<-----.....but if your intake IS reversible on the LS it should be a lot neater and simpler.

Vettegineer

I had not really considered that--it'd free up the rush for air in the front. Pretty crowded up there with electric fans on the radiator and ac condenser--the stock air intake over the radiator is only about two inches tall at most. I need to dig into that idea a bit more!

That dude with the Delorean is gutsy...I bet he'd like an LS2 or 3 now! Of course with all the changes he made changing to a bigger bore would be cake for him.

I'll need to search around to see other pics of that style of air intake--it was stock in what years/models with the carb? Might lift the hood a bit--L88 hood lifted you 2 inches--or more? Any sound from that on yours--I mean pulling in along the windshield...

I can't believe no one else has done that yet with all the LS swaps...
Les

Garys 68

On my LS swap, I didnt have room to run the air intake right or left due to the AC compressor and alternator. And I was using a mechanical fan, so strait ahead was out of the question. So with the L88 hood, I wrapped around the intake tube, and put the filter on top of manifold. It draws air from the back of the hood.


Another pic.
In progress, the metal hold down box was intended as a temprary fix, but I never swapped it out. I also mounted the TAC module to the back.

Vettegineer

That looks pretty slick too--similar to CarriLjc--do you have another pic from up toward the driver so I can see the rest of the filter box? Never seen one with mechanical fan--pretty innovative!

Gordonm

I have a set of Melrose headers on mine and they fit good and look good but ground clearance is terrible. I had to modify them to fit the rack system which they were supposed to fit without a problem. One tube was modded and the guy did a great job but these were expensive headers that were supposed to fit right out of the box. The ground clearance is at best about 2 inches. Terrible. My car is not lowered either. Just about stock ride height. I also have a set of F body headers that give good ground clearance but the outlets are not optimal. Still up in the air on what I need to do. May again modify the Melrose headers, more money then I would have to recoat them, more dollars or modify the F body headers.

As for the cold air, I have been looking into this also. I have an L88 hood and was looking to go on top of the radiator and fab a cold air system also. Most guys go behind the radiator with a 90 degree bend and a cone filter. This is still hot air and will retard the timing due to the hot air therefore reducing power. My setup should make around 520HP so I want all I can get.

Unfortunatly my build is at a stand still. Going through a divorce and the car is just sitting now and it will be a few months before I can get back to it. Pretty bummed about it. You can see my progress though by looking at my build here.

http://forums.corvetteforum.com/c3-t...o-my-72-a.html

Vettegineer

Gordonm--couldn't be sorrier to hear about your trouble--God knows I've been there and it's a rough road.

Thanks for the feedback on the Melrose headers--I'd hate to pay 900, then not be able to lower the car--or easily install the rack system. Funny, I'd been looking at the F-body headers too. I'd really wait for someone to chime in with great fitting headers on their LS3 install. I'm not sure if the headers matter between LS motors. Did you go 1/2" forward or what? I'd pretty much decided that--and plan to use the manifolds while I run the engine for the first few thousand miles anyway. Anyone using the Kooks headers? Sure are pretty to look at.

Peace Les

Garys 68

Befor you spend too much on aftermarket headers, read this:
http://www.carcraft.com/techarticles...e_header_test/

Vettegineer

Interesting read--I had heard that the manifolds were much better than what used to be stock manifolds. The 2009 date, and the design of the headers they used in the test may be part of that result--the collectors are about 5 inches--and the LS1 is a new platform that may "overshadow the sbc juggernaut", so it makes me wonder--what has been learned about headers for LS engines? The point is, that on a budget, dropping 1000 there isn't as important as it once was--so my plan of starting with the manifolds is a good one.

I'd still like to know what headers actually do bolt right up--and not struggle with getting around a rack--or ground clearance--and also WHERE IS THE BEST POSITION TO MOUNT THE ENGINE? 1/2" forward came from the guys selling Melrose, and I'm not buying them based on Gordonm's feedback.

I looked closely at the K&N C5 & C6 cold air intakes, and asked them for CAD models or drawings to see if they could be made to fit. I saw one builder who built a 79 w LS3 and it looked like one of these with an extra piece of inlet tube.

Thanks for the answers--please keep them comin--I need to get this stuff ordered before the cash in hand disappears on family stuff!!!

Vettegineer

It looks like several sponsors on here for headers--how about it--Kooks, A.R, LG?

texas jim

Can you not get a good quality header kit(good material) and make a good set? That way you could have the best material along w/ exact pipe length f/ each cylinder, which even the better headers don't have. I know the good kits aren't cheap either, but atleast if you spent a grand, you'd have a perfect fitting set.

Vettegineer

Making them is definitely feasible--I'm not sure how they tune the length to "scavenge" the exhaust between valve positions--but I had though about trying my hand at it with Ansys. I'm not sure they would fit perfectly if I did it--though I do have some friends that could weld if I drew them. Seems like more work then fun almost, and this is supposed to be fun! Lol!

I see LS install kits for all kinds of things (Volvo?!) and don't see one for a C3 Vette? I wonder why!

Gordonm

Here is a setup I would like to use and will build it someday

gdh

Gordon, anymore pics of that setup - just incredibly clean!

Gordonm

I have tried to get more pictures of that setup but I can't remember where I got tha tfrom. I would like to duplicate this or very similar to this when my build resumes. Yes very clean setup and it would draw the air in over the radiator. I have an L88 hood so this setup could work nicely.

Garys 68

If you're running a MAF, you can have problems with that type of setup. At partial throttle, airflow is only at the top and bottom of the throttle blade. If the MAF is too close, it will give incorrect readings. An SD tune will eliminate the MAF, but that's a step backwards IMHO.
I've seen a few of these on later vettes that put the whole filter in front of the radiator. I would imagine you could mod or make one for a C3.
http://www.ebay.com/itm/K-N-57-3020-...cded51&vxp=mtr

Gordonm

Gary, Yes I have heard that also and would rather do the setup in front of the rad. The probelm is wit hthe current hood design the hood will not be able to open fully. I have tried this. My brother in law in his 67 modified the hood hinges so the hood picks up like the newer Vettes. This works very well and looks really cool but requires mods. Also the rad. support has to be modded in order to get it over the support and under the hood. Like I said I have more work to do once I get back to the project. Definitley a better setup though the one yo usuggest. I was just throwing out options

Here yo ucan see on Jeffs car the hood opening up differently and the cold air over the radiator. He dropped the support down some and modded it. Obviously everything on this car is custom

cv67

Dont think youll ever see a measurable difference but personally I like the idea of cooler intake air also

Think cooling the fuel would help more.

Gordonm

The newer cars will retard the timing quite a bit with hot air vs cool air so yes there is quite a bit of difference. It will knock out as much as 10 degrees timing if my memeory serves me right. Olus cool air dsefinitly makes more HP. On a 200 hp low performance motor not as much but when you get up into the 500+ HP a cool dense charge will give you quite a bit more performance.

74modified

Not a C3, and depending on your clearance