Mrwilson

From what iv driven, i am not a fan of a single bore Tb (or likewise 2bbl carb)
Every car that has a duel bore Tb (or 4bbl) seems to me to be much more responsive in a daily driver/redlight racing setting to me.

Is there a Duel bore Tb for the LS1? is there even an intake manifold set up to deal with the increased flow of a duel Tb?

BOONE

iTrader: (4)

There is a 4 bbl intake setup but i would stick with the stock type, they have great throttle response compared to all old school hot rod cars from the old days especially if its forced induction. You are really looking at cfm of the throttle body and the intake design behind it. A ported one can flow in excess of 1000 cfm and then you can breathe on that some more too if ya want. Stock ported tb and a ls6 intake is pretty decent performing, you would not be disappointed.

gwj

What makes you think a dual will flow better than a single on an LSx manifold, with one inlet? It would seem to me to totally change the airflow dynamics. Not trying to be antagonistic, would like to hear your reasoning. Now, an individual TB for each cylinder on a high performance app, I can see. Which of course would have to be a custom intake, or one of the Aussie manifolds.
gwj

gwj

When you are talking about a 2bbl vs 4bbl carb, that is not a good comparison to an EFI intake where the computer adusts the A/F.
Besides, a 4bbl carb has primary and secondary bores and the fuel enrichment can be adjusted better for WOT + the increased airflow of the secondaries (vs a 2 bbl carb).

Mrwilson

right, but im not compairing a carb to a TB, im just saying...with a duel bore and 4bbl carb, there is/are primariy(ies) and a/are secondary(ies)

Um, actually i dont think i worded my question correctly about the increased flow. What i ment, was as you said gwj, the flow charisterics would be diffrent.

Im not talking about increased flow, just diffrent application of throttle.

ShevrolayZ28

iTrader: (4)

I don't know for sure but I think the only advantage to having a dual throat TB is space saving or fitment.

My Cobra came with a dual TB. I suspect if they tried to use a single TB that flowed as much it wouldn't have fit under the hood.

Just a guess.

slowpoke96z28

iTrader: (2)

two smaller orifices will net a higher velocity than one big one, giving it better part throttle driveability and throttle rsponse. its the same reason people dont just hog their cylinder heads out or run manifolds with no runners. intake charge velocity. yeah, a single opening is what the gm engineers choose because they weren't after low end(tip-in) throttle response. it would tak alot of homework and money to keep the benefits of a single port throttlebody while adding the benefits of a dual port throttlebody. there is a lot more to it than just this, but it should give you a basic idea.

Mrwilson

yeah, that pritty much answers my question..thanks.

but, what are the benifits of a single bore? Not that im saying there are none, i just dont know cuz i just never cared for them.

I mean, if i get a manual trans, there realy is no problem...but thats a diff story with an auto i guess.

300bhp/ton

sorry that doesn't make sense to me. the engine will repsond the same with an automatic gear box as it will with a manual. There may be a difference in responsiveness but this will be drivetrain related and should not be confused with the engine itself as they are totally seperate issues.

In addition I would say the engine response if actually very good at low rpms even with the auto box. This comes from some one whole also has a 4brl setup carb on a tuned Rover V8, and a EFI V12 Jaguar with twin TB's.

I'm not saying it can't be imporved upon, but I think most noticable changes would be in the drivetrain. A shiftkit and a stall would make a big difference, as would leaving the shifter in D (3rd) and not OD (4th), if need be you could even manually hold the box in gear. Combine this with a lightweight flywheel, free flow exhaust, LT's, lid, ported throttle body, ls6 intake and most importantly a TUNE. I honestly doubt you'll still feel the need for a twin bore TB.

ShevrolayZ28

iTrader: (4)

I like that better than my explaination (my guess lol). But the air stream is merged again as soon as it leaves the dual throat TB, does the air slow down again?

Mrwilson

if your intake manifold were designed to compensate for the diffrent airflow, i dont think so, but just pulling into a single bore tb designed manifold would prolly slow it down again, and would prolly not let the duel bore be used to full efficancy.


im not talking WOT, but the selectability of "tip in" power you can have.
With a single bore you either get open, or closed. and with an auto trans...if you try to open it more for more power...you may end up downshifting. With a duel bore, if your not getting enough power from the primary bore, you tip in a bit more, and start opening up the second, and giving you more power without having to downshift.

With the std tranny, you could just leave it in gear, and open the tb up to however much you want.