Originally Posted by rons 00z

just a FYI guys my cam is a 247 252 @108lsa in a 383 lingenfelter CNC heads 11.2:1 SCR and it has the harrop 52mm intake. the cars idles fine at 900rpm and only bucks from 1k rpm to 1.5krpm in first gear. ******* car is almost like stock but pulls like a raped ape.

Originally Posted by Beaflag VonRathburg

Do you have any pictures? What did you end up doing for filtration?

Originally Posted by rons 00z

i just took these.
http://i135.photobucket.com/albums/q...z/P7290006.jpg
http://i135.photobucket.com/albums/q...z/P7290007.jpg

as you can see i have about a blond **** hair of room to work with. i had to chop that plate thing off since harrop wanted to charge me 1k for new air horns that were separate. so i said **** it and hacked away. now i have alot more room to work with but not enough to use a regular filter like the singles that are 4 inches long from K&N. i did find something thats like a screen with a foam deal that goes over the tip but it's like $20 a pop so i'm really putting that off. heres the link to the only thing that looks like might work.

http://www.hilborninjection.com/prod...=363&CatId=132

Originally Posted by Beaflag VonRathburg

I plan on starting on making my own setup really soon. I already bought two sets of 2007 GSXR 750 throttle bodies. I forgot to measure the first set of shafts, but each runner tapers down to the back throttle bodies which are 42mm. They also have two sets of injectors in them. I'd like to leave the back set and use it with a stand alone fuel cell to control a dry direct port. Here's some pictures:

Originally Posted by 3.4camaro

8-50mm diameter tb's= 15705 sq. mm. surface area of throttle body.

1-105mm tb = 8654 sq.mm. surface area.

So the ITBs have a little less than twice the throttle blade surface area. Maybe that's why ITBs outflow a beck intake and tb.

In a ITB setup, each cylinder gets its own air supply. This means that each cylinder creates its own vacuum, and 1 cylinder doesn't suck on the supply of another cylinder. Maybe this raises the deltaP, because the air on the outside of the valve(in the intake runner) isn't being sucked(causing a low pressure) by another cylinder. This keeps the deltaP higher than it would be with a traditional single tb setup, and we all know a higher deltaP moves more air into the cylinder.

This make any sense to anyone?

Originally Posted by racer7088

Originally Posted by racer7088
The independent runner stuff with the small independent throttles before each port with the constantly pressurized near 100 kpa "mega plenum of the world" above those same little throttle bodies are just less affected by the exhaust reversion that affects a plenum car worse since the whole intake system on these setups is at very low pressure and the exhaust is at such a higher pressure. The exhaust reversion can and does fill up the whole plenum behind the central TB or carb and the whole runner of each cylinder with exhaust diluted air that causes the repeated and erratic misfiring that we hear as the cool loping sound some people love so much.

With enough overlap the IR systems will also lope too and turn black under those cute little throttle bodies from idling with all the same vacuum under them when they are closed and idling but they have less of the total runner to become as contaminated since the higher pressure is close at hand right above them and in the rest of the runner. You will sometimes, with really big cams in these systems see the exhaust and regular reversion in the form of standoff above the runners with some of them at lower engine speeds.

Also when you crack the throttle instead of an entire manifold plenum having to pressurize up slowly instead, now the port sees full atmosheric pressure and density basically almost instantaneously so the throttle response is WAY better. In fact some people need a progressive linkage or it's too jerky for them! Also just realize that Australians ARE crazy and they all drive cars with blowers and NOS and have mohawks. They also like cubic inches in a lot of their racing and RWD but that's finally coming back to the USA too as people here have had their fill of the FWD crap.

Originally Posted by J-Rod

I agree with the above post that those are too small. I'd look for something between 50-55MM. You find a lot of stuff derived from carbs to be around 42MM as that seemed to be about the limit for good signal for a carb.

Originally Posted by Beaflag VonRathburg

Will they be too small even with the taper to increase velocity? I still need to measure the inlet side's diameter.

Originally Posted by GrannySShifting

You have a multiple thousands of dollar intake, a vacuum pump, and your letting $20x8 hold you up?

Originally Posted by Drew04GTO

Yes, even with the taper you lack the cross sectional area to support the CFM the motor needs. I don't want to sound like an *** but I quite honestly wouldn't be suprised if it lost power over a stock intake on a stock LS1. I know that's a bit harsh but I hate to see people waste more money than they have to. Letting you know about these shortcomings now will save you a bunch of time and heartache.

I've been looking quite a bit at home-built ITB setups for a while and it seems like on healthy honda motors (300+ cfm at less than full lift, lots of RPM and big cams) Hayabusa throttles seem to be the only ones that don't loose 20+hp up top. Yeah, they gain a bunch in the mid range but drop off early.

When I was looking at making an ITB setup for my car I was going to use IIRC Acura Integra LS throttle bodies as I believe they're 55mm stock and can be had for pennies.

Originally Posted by J-Rod

I agree with the above post that those are too small. I'd look for something between 50-55MM. You find a lot of stuff derived from carbs to be around 42MM as that seemed to be about the limit for good signal for a carb.

Originally Posted by LSOHOLIC

So.........it seems I'm late to this thread. Would it be possible to get a list going of all the companies making ITB's for the LS ??

Because I have noticed that some of the links to "said" companies making these is ITB's are dead....


Thanks.........

Harrop
Higgins
Hocking
Jenvey
Kinsler
..??

Originally Posted by Cheatin' Chad

I had dual 48mm Carbs on my Honda VTR and it was a bear to tune. I believe they were the biggest carbs used on a Honda ever.
.

Originally Posted by rons 00z

i just took these.



as you can see i have about a blond **** hair of room to work with. i had to chop that plate thing off since harrop wanted to charge me 1k for new air horns that were separate. so i said **** it and hacked away. now i have alot more room to work with but not enough to use a regular filter like the singles that are 4 inches long from K&N. i did find something thats like a screen with a foam deal that goes over the tip but it's like $20 a pop so i'm really putting that off. heres the link to the only thing that looks like might work.

http://www.hilborninjection.com/prod...=363&CatId=132