I never thought I would be posting about a TPI article on here but the info on the HSR and the Single plane are interesting.
http://www.compcams.com/Community/Ar...?ID=1737510521
Another good one:
http://www.compcams.com/Community/Ar...p?ID=-61543841
Its all old news but worth reading......

 

Free your mind.

 

Air distribution. There are drastic differences between the port flow of the low (bottom plane) entry runners and the high (top plane) entry runners - as much as 30 cfm. With a carb, the fuel stays with the air, so the cylinders that are starved of air are also starved of fuel. With port injection, you give all the cylinders the same amount of fuel, so 4 run rich and 4 run lean.

 

It's nice to talk about theory of dual runner intake manifolds, but the fact of the matter is that a well-designed intake manifold for a 2-valve motor doesn't need 2 lengths of runners. A well designed intake manifold (LSx) has medium length runners with no kinks, smooth surface finish, and a fair amount of taper. You basically get the torque advantage of the length, with alot of flow from the size and finish, plus the added benefits of taper. I think you would be hard-pressed to top a LSx intake manifold with a dual-runner/valve intake.

All this is a moot point, though. Only 1 in 1000 people who say they are fabricating an LT1 intake will actually do it. I bet no one ever builds a dual-runner/valve intake, so discussing it is really wasting time. I would be VERY interested in seeing an LSx style LT1 intake, though. It would work well, assuming it's designed right, and it might actually happen.

Mike

 

Mike,
If ya ran the Hilborn set up that goes direct into the chamber right next to the plug the fuel would be the same. Then anything coming from above would be air only.
Have used there in sprint cars a few years back but they had maintenance problems 'cause the nozzles needed maint EVERY time they were run. The old nozzles in the intake worked as good.

 

Well i'm going out to the garage right now, picking up my air tools and fabricating a new LT1 intake!!!!

Right after I finish my twin-turbo, over-head cammed, variable timing 355.....

But seriously, I agree with engineermike. The LSx style intake seems to work well and you don't have any of the hood clearance issues. Obviously you would have to redesign it to fit the port pattern on LTx heads. Maybe someone with knowledge of plastics casting could manufacture a composite intake?

 

Come on, I want pictures

 

The LS1 manifold is an interesting hybrid of the TPI and LT1 stuff and is cleverly packaged to get good runner length in a small size, that's what made it interesting to me from a design standpoint . As far as the basic LS1 design being optimal, many people seem to think the LT1 motor has more low end punch than the LS1. If that's true it might owe to the fact that the LS1 runners while longer are also a lot bigger diameter which would negate some of the charge tuning at lower RPM's. I'm not convinced that the LS1 intake is so well designed that dual stage intakes offer no clear advantages. Having driven them they were much less engaging in the lower/mid range than the old TPI cars even though their cylinder heads are much more advanced. For the most part it seems that one moderate length runner is a workable compromise that gets the job done for a reasonable price. With available technology could a setup be constructed that would ram the charge past the intake valve much better than an LS1 at lower RPM's while still having superior top end pull too? I believe. I believe

Help me up, I've fallen and can't see. I was blinded by a bright light!.

 

grammarman, I invite you to build one then. Please.

And BTW, the LS1 isn't the first engine to use that style of runners and plenum beneath it. I've seen it on foreign V-8's, even domestic V-6's for many years. In fact, the Dodge 318/360 is the same layout. It just makes sense on V engines with limited hood clearance.

Mike

 

I have a question... Supposing, that I want to go with a professionally built sheet metal intake from Hogans or Wilson. What all information is necessary to provide them to build the best designed intake for my setup?? Obviously designing an intake is a very complicated process, and probably should be left to professionals with several years of experience in the area. So is getting the best sheet metal intake as simple as a phone call away? - by providing information such as: I have an 381 LT1 with GM LT4 heads which flow XXX, and these are the cam specs XX ? or do you need to provide more detailed specs that you want to have the intake built to?? such as what volume that you want it to be, and what length you *think* the runners should be, and etc. ?

 

I'm sure the people at Wilson or Hogan will be able to give you some expert advice based on the engine you have. Most importantly based off of the cam/heads combo and your goals for the project. I'm sure it would be easier if you already knew the plenum volume and runner length desired, but I'd rather let the experts figure it out.

Jeremy

 

a really well built sheetmetal intake will require the block and heads to be present.

 

Just watching

 

Found these:











It's apparently a C5R intake built by Harrop. I can't even begin to fathom what tuning something like this must be like.

 

It looks like it might tune itself...probably should for what someone might pay for it. Either way it appears to have adjustable valves in the runners, what do you think about that 1racerdude?