LS3 + Carbs ? + other tuning related

[Phantom Mark]

Anything to be gained by getting a good Carb setup on the LS3 engine out of interest ??

Still trying to learn what is worth it and what is not worth it, im not a millionaire so any investment I make into tuning this engine I want a worthy return, im not ignorant to the fact tuning petrol engines is not cheap however.

I am so far not keen on the the supercharger "whine", maybe I can grow to like it when I need more power than the NA option can provide, not sure turbo's will be in keeping with this kind of engine ?

I would really really love to hook up with anyone local to Sleafaord nr Newark/Grantham Lincs who has ANY mods on their cars to experience it for myself if thats possible please ?

[ringram]

The intake wont be the restriction initially. For best power NA stock setup get a 1-7/8 dual 3" exhaust and an otrcai intake setup like Donkv8 or similar. You want cold zero restriction intake.
A set of higher ratio rockers will also help.

But your best bet is a mild cam which should get you well over 400rwhp and give the old LS2 SC setups a run for their money. A popular effective one for the LS3 is the comp xer224-230-114

Tiler recons 400rwhp is possible totally stock with exhaust, intake and tune, so you have room to move already even without cam.

Plus a carb setup will throw so many codes I doubt your car would even start!

[granada203028]

The engine would look very pretty with a quartet of IDFs!

[ringram]

+1 if you want something that looks nice search for Harrop Hurricane or Kinsler intakes.
But they cost mega ££

[stevieturbo]

You would only fit a carb as a last resort...or if for some reason fuel injection was simply out of the question.

A carb will also make for a very tall engine, some 6-8" higher than a comparable efi setup.

Why would you want the carb option ?

[Phantom Mark]

thanks guys, learnt a little from the replies so far, im a complete newb tuning one of these motors so some of the terms and "tuning" talk went straight over my head

It was only for the fact that on smaller engines at least a decent Carb setup can release horses quite easily, like on BMW 6's or many of the 4 pots, just wondered if the same principles applied to the 8, of course now you mention height it would be totally stupid and out of the question in any case.

@ Ringram, thanks mate, you have given me hope NA will suffice for the time being

Could you roughly estimate how much it would cost to get me to the 400rwhp from where i'm at now ?

Its just so I know how much saving im gonna have to do lol........buying the car skinted me pretty much for the near future so having to budget sensible and plan sensible for all my mods.

Very big thanks again for lending your experience guys.

[stevieturbo]

A well set up fuel injected engine will always produce more power than a carburettor engine, regardless of size, cylinders...whatever.

Just because many other engines have a very restrictive efi system, doesnt mean carbs are better.

[Drew SS]

stevieturbo said:

A well set up fuel injected engine will always produce more power than a carburettor engine, regardless of size, cylinders...whatever.

Just because many other engines have a very restrictive efi system, doesnt mean carbs are better.

why dont dragsters run fuel injection then is it because of the fuel they run

[stevieturbo]

Drew SS said:

stevieturbo said:

A well set up fuel injected engine will always produce more power than a carburettor engine, regardless of size, cylinders...whatever.

Just because many other engines have a very restrictive efi system, doesnt mean carbs are better.

why dont dragsters run fuel injection then is it because of the fuel they run

Good question.

Although I think given the nature of those engines....efi probably would be very complicated, and perhaps not worth the hassle.

Those engines dont operate under a variety of conditions, and are pretty much WOT, and a single operating speed for the duration of a pass ( clutch slips for the duration of a pass too to control power delivered to the axle )

I'd hate to imagine the size of injectors and pumps required to feed one though !

[Boosted LS1]

I doubt dragsters are into precision metering like efi can produce. They need to shovel it in in bucketloads and at the end of the day at full chat efi and carb's will make the same power. Also could their fuel fk up injectors and maybe the rules prohibit efi?

Perhaps they're more concerned with clutch packs and traction.

Where's that Slinky fellah?

[ringram]

Actually all out efforts use carb intakes in place of the composite factory intakes. The factory intakes are limited in flow due to packaging requirements etc.

[Phantom Mark]

@ Ringram, thanks mate, you have given me hope NA will suffice for the time being

Could you roughly estimate how much it would cost to get me to the 400rwhp from where i'm at now ?


tia

[gsd2000]

ITB's

[stevieturbo]

ringram said:

Actually all out efforts use carb intakes in place of the composite factory intakes. The factory intakes are limited in flow due to packaging requirements etc.

As GSD says..an all out n/a build would use ITB's

With boost....many use the carb intake, for whatever reason. I just did it because I like the look.

I dont believe for one second it performs better than the standard LS6 intake though.

I'd like to try one of the new Edelbrock manifolds though.

[bobchevy]

Boosted LS1 said:

I doubt dragsters are into precision metering like efi can produce. They need to shovel it in in bucketloads and at the end of the day at full chat efi and carb's will make the same power. Also could their fuel up injectors and maybe the rules prohibit efi?

Perhaps they're more concerned with clutch packs and traction.

Where's that Slinky fellah?

[bobchevy]

bobchevy said:

Boosted LS1 said:

I doubt dragsters are into precision metering like efi can produce. They need to shovel it in in bucketloads and at the end of the day at full chat efi and carb's will make the same power. Also could their fuel up injectors and maybe the rules prohibit efi?

Perhaps they're more concerned with clutch packs and traction.

Where's that Slinky fellah?

You are right the rules prohibit efi in most classes of drag racing, the majority of blown cars and bikes run mechanical fuel injection [ none electronic ], petrol or gas is normally for carbs, methanol and nitromethane is injected n/a or supercharged cars + bikes.

[ringram]

stevieturbo said:

ringram said:

Actually all out efforts use carb intakes in place of the composite factory intakes. The factory intakes are limited in flow due to packaging requirements etc.

As GSD says..an all out n/a build would use ITB's

With boost....many use the carb intake, for whatever reason. I just did it because I like the look.

I dont believe for one second it performs better than the standard LS6 intake though.

I'd like to try one of the new Edelbrock manifolds though.

Agreed on ITB but Ive seen dyno's composite vs carb with the carb having more power. For example..

http://www.hotrod.com/techarticles/engine/hrdp_090...

"Comp's mildest cam is also its most popular. Even with only 216/220 degrees duration at 0.050, the XR269HR-14 was able to make nearly 500 hp with a carburetor; more than 480 hp with EFI."

[ringram]

As per above

"That the carb outperformed EFI on top is no surprise; it's in line with what we've seen on past carb-versus-EFI smackdowns. In this case, it seems that the EFI intake posed a high-rpm restriction, as the carb'd intake allowed as much as an extra 500 rpm, and rpm with supporting airflow means more horsepower. "

[stevieturbo]

Looking at the pics...that article used a standard LS intake manifold.

That isnt a fair comparison against a high flow carb intake and carb setup.


Fit ITB's or a good aftermarket intake, and then test the carb against efi.

[ringram]

I think they used the LS3 intake, which is supposed to be pretty good.
But ITB should beat it for sure.