I've been around SBC motors for years.Why is it so hard to get major power from a fuel injected SBC?Popular Hotrodding always has some 350 making 500+ hp and it's streetable.About 3 times a year they show how to build combos pushing 450, 475+ hp.These are always carb motors with no emissions.In Florida we don't have emissions testing, so thats not a problem.

We run the same exhaust, short block, we can buy good flowing heads, so it has to be the fuel injection or limited variety of cams.

I just looked back though the PHR engine masters challenge. The winner laid down 604HP @ 6,500 rpm from a 355 ci .With only 11.4-1 compression ratio.And the editor said he's seen a lot bigger cam in street cars.These numbers are from the crank, but do we have anybody pushing 425 rwhp with a 350 and no nitrous or forced induction?

What gives?

:skep: :skep: :skep:

 

I think it is just easier to do it with the carb. I never had much luck with computers in cars when it came to mods. But if you go "Old School" it seems the sky's the limit.
:auto: :auto: :auto: :hurray:

 

You can get the same power numbers, you just have to pick the right intake setup.

You dont have to get a computer program if you dont want it, its not recommended, but the computer part is tough for a novice and its required for cam changes on an injected motor usually.

 

whats so hard about 500fwhp?

500rwhp is another story.
TBI/TPI just sucks

SPFI- we are dealing mostly with LT1. LT1, you dont have thee cylinder head options and intake options you do on the gen I.

Then the LSx ate them all.

 

[QUOTE]You can get the same power numbers, you just have to pick the right intake setup.

intake intake intake intake intake intake emissions intake

 

:lurk:

 

Typical carb engines build peak torque at higher RPM than C4 EFIs so of course the HP numbers are higher but don't foreget to look at the HP/Torque curve.

An engine can be "streetable" and still run a very different torque curve than our SBCs.

One advantage of building big HP with an EFI engine is that it will do it in various weather conditions wereas a carb motor may require jet changes.

Don't throw away your LT1 just yet; stroke it out to 383 and add the right ingredients to build some decent HP numbers.

 

I don't believe it's difficult at all... EFI can make the same power as carbs (and often better) plus they offer a broader power band than carbs. The jets, metering circuits, pump shot, etc are all generally tailored for a single specific operating parameter; EFI can be tailored to MANY different operating parameters in the SAME map. Good modern street carbs generally have seperate idle circuits whereas everything is built into the single components in EFI. Now that being said it IS simpler to take a carbed motor and jet it for max torque/hp if you're not concerned about part throttle or idle characteristics so it is an "easy" way out. EFI when properly tuned will be more consistent...

There's relatively little difference between an EFI SBC and a carbed SBC except the induction system. If you're talking about OEM style TPI manifolds then you are certainly going to pale in comparison with a dual/single plane carbed motor of the same stats...Camshaft selection is also much more critical on EFI combinations running TPI, modified TPI (like a SR), or the LT1/MR manifolds when compared with a carbed dual/single plane. But when you even the playing field with an EFI converted carb style manifold you'll quickly realize EFI gives up nothing in power consideration and will often make MORE power over a broader rpm range; and do so with a smaller BSFC.
-Jeb

 

SPEED &%) lives in Florida so he doesn't have the colder weather to deal with.

Another big factor here is money. The same equiptment to make = power to a carb will be at least $1500 more. Jeb is right the EFI can work better when fully dialed in , but that may take many hrs on tuning to acheive.

I remember reading in GM high tech a swap to a holley stealth ram and it made 10 more ft lbs of torque and 5 more HP tan the carb. It only took 20hrs of tuning to get it there and they admitted it still wasn't perfect.

 

:lurk: