I'm 6', but my seat is solid mounted 1/8" off the floor. Adding a seat cushion has helped, but I don't like doing anything that will raise the CG of the car. Below is a picture of my car. The hood scoop doesn't look real tall. But like you said, 1" can make a big difference. 2.5" can make a huge difference.

 

Since a c4 can pull over 1g stock and I'm sure you have a better setup. I don't think raising you and an aluminum racing seat up an inch or so would change the handling characteristics of your car. Provided you have helmet clearance.

 

You may be better off adding ballast to make weight, if you like your current setup.

 

Yeah, I agree that my butt being 1" higher isn't likely to make a measurable difference. It's probably more psychological than anything. But it's the little things that add up.

 

have you looked into the c5 corvette oil pan? It is more shallow than the camaro and truck pans.

 

I originally thought about trying one of the C5 pans, but other guys who did the LS/C4 swap said they wouldn't fit. Apparently the F-Body pan is the only one that clears the crossmember/frame. So I used the F-Body part & added baffles.

It would be cool if that information was incorrect.

 

I think I have found a solution to the "height" problem, so the carb setup will come back into play. So if I'm looking for max area under the torque curve from 2500-7000, is the carb still going to be a better setup than the FAST Intake & TB? At what point is the EFI system better? It's hard to imagine all that fancy technology hasn't found a way to make up for the lack of max timing. If the carb is better for max performance across the board, then why do I hardly ever see guys running it?

I understand that there are always compromises, so I'm trying to get an honest assessment of what the downside of the carb setup is.

 

It looks like the Batwing pan fits, and is about 3/4" shallower sump, but long tube headers won't fit. So the C5 pan is out. But it looks like the LS2/LS3 pan is also 3/4" shallower (and without the wings). ImprovedRacing website says they are going to be making a baffle system for it. Yesss!!!

 

People don't run carbs because they are either lazy or don't know how to tune them. It is much easier to sit inside the car and fiddle with a laptop or just have someone send a tune to upload to the pcm. Plug reading is a lost art, jet changes can be no fun, changing squirter size and cams is becoming a lost art also. A/F ratios are easier to see on a computer screen and changes are less labor intensive.

 

Would the rules allow boring the 5.3 ?

you could bore the 5.3 (3.78") out to an 5.7/LS1 3.898" bore size (sonic check 1st) and use the 5.7 pistons (or full rotating lower end and therefore have an iron 5.7 ?. This has been done many times.

BC

 

The short answer; we hardly see guys running a crab because most LS powered vehicles are street & track cars. EFI is far superior in getting best street fuel mileage, comes on a stock LS1/LS6, LS2, LS3 & it's expensive to do a carb swap. There's emissions to pass, in many States now, & EFI w/ OBDII is usually required (not always). The EFI intake generally tops off @ .600" lift. Guys use higher lifts in order to increase the under the curve power. Plain & simple; the carb intake breaths better.

Downside to carbs are fuel mileage, oil change intervals, emissions, cold start, hood clearance (lol), intake weight, limited programming (MSD LS6). Can be an off throttle to on throttle bog if not set up correctly. Am sure there's more, but can't think of any.

Carbs are tunable using a wide band A/F meter & knock sensors for feedback. That's how I tune mine.

If you were to choose EFI, don't put a FAST intake on an L33 (5.3L). Especially, not on a road course car. LS6 intake will make more under the curve power/tq down low because the air flows faster through the LS6 runner than it will through the FAST runner with 5.3L displacement. I have done a lot of LS6 intake testing (measuring flow/pressure) in real world LS1 applications. The FAST & LS6 are both excellent intakes for 5.7L & larger displacement engines. Again, w/5.3L an LS6 intake is all you need.

 

The rules only require that my motor is automotive based. Beyond that, I can do whatever I want. It would be silly for me to bore out the 5.3 for more displacement. My minimum legal weight is based on my displacement, which is the reason for considering the 5.3 in the first place. (Min weight with 5.7 = 2226lb; Min weight with 5.3 = 2154lb) Creating an Iron 5.3 (or 5.7) does nothing but add needless weight to the front of the car. And THAT is bad.

 

Thanks for all the great info. I'm not the greatest at tuning carbs, but also know that it's not real hard if you are willing to take the time to learn. In the past I've always had co-drivers that were good with carbs, but now I'm going to be on my own. I'm an old school kind of guy, so it's great to know that I can run at the pointy end of the field with a carb setup.

Can you recommend a source for learning how to tune my carb using the wide band A/F meter & knock sensors?

Thanks,
BeerMan

 

Carb & then the PCM/tuning section (has good tuning parameter info related to engines, not just PCM tuning). A/F ratio @ WOT needs to be around 12.6-13.0 without engine knock. The reason for the A/F meter is to confirm A/F ratio that produces max power & max torque @ max safe timing without engine pre-detonation (knock). For example, max torque might be 12.8 @ 4000 RPM & then max power created from 4200 RPM to ... RPM @ 13.0. Part throttle should be stoich, 14.63 A/F ratio; part throttle from idle to say 2800 RPM. A very good carb that comes with all of the needed tuning parts/options are the Quickfuel line of carbs.

 

A LOT of good information here. Some counter thoughts I had. When I auto-x the percentage of time at WOT above 5500 RPM was maybe 10-15% of the time depending on the course layout at that event. That being said would the weight reduction/lower center of gravity of an EFI manifold say LS6 or a FAST78 counter or possibly outweigh the the gain in WOT horsepower. Just food for thought.

Now a question, would there be a considerable difference between setups in the 3k-5k under the curve area?

 

yessir just put a 4.8 crank in it......

 

yessir just put a 4.8 crank in it......

 

4yrs later

 

You're the Jesus of the Conversion forum...LOL

Andrew

 

no, apparently I'm a teenage troll!!!!!....nowadays...they are trying to spike me to a cross!!!!! But thank you I will take that as a compliment. .....