Pro Stock John

iTrader: (34)

I had a 4.060 bore iron block twy years ago and even that was aggressive.

Like Gordon said I would go 4.000 or 4.030 at the most, 4.125 is not possible.

LSs1Power

iTrader: (5)

I dont know why people keep talking about going with C5R or Iron blocks.... I never heard of a LS1/LS6 block crack under boost soo far. Did u guys see a LS1/LS6 block crack from boost?

Evil F1 SS

Three reasons why the LS1/LS6 Block isnt as good as the Iron/C5R blocks.

1.The aluminum blocks distort more. Bad cylinder sealing and bearing wear that can lead to failure.

2. The bulk heads break (sp)

3. The threads in the block stretch under higher boost. Head lifting problem is less with an iron block.

Thoes are the reasons i have found or been told by shops.

INSOMNIAC

As far as I know, under high tensile forces stock LS1 / LS6 blocks start deflecting and moving which results in lifting of heads. That is the reason you don't see many people cracking the LS1 or LS6 block cause you will lift the heads way before cracking the block. Now, boring the LS1 / LS6 to higher 4.000 or higher bores reduces the cylinder thickness and makes the block more prone to deflection under tensile forces. C5-R block is manufactured to withstand much more tensile forces than the LS1 / LS6 although all of them are aluminum blocks. And the iron cast block is resistant to any deflection because of material property. It's massive iron and is not moving anywhere.

blu00rdstr

HP and Torque curves always cross at 5,252rpm, and the big motors have big torque down low, the small motors have to keep on revving to get a high HP number. I wish there were a number to describe the total area under the curve, this may put 500HP of a rotary in perspective with 500hp of a big motor. Not sure if you're talking rwhp, but with big motor cars we always talk rwhp. My first cars were Datsuns which had to furiously rev trying to keep up with the big cars, car seemed like a terrier among rotweilers. At least until I put a '63 olds aluminum V8 in a Datsun 1600 convertible.

BIGBOS

Build a 370 motor

6.0L iron block .30" over with a stock 5.7L crank

stealth

I have a 6.0 litre CI block bored to 4.06 that has made 869 rwhp on a Mustang dyno with ~17 lbs. of boost (last year). I agree that 4.06 and maybe 4.08 would be the max, but I have no real evidence to point to.

Pro Stock John

iTrader: (34)

With the amount of core shift in a 6.0 block, only a select amount can take a 4.060 or 4.080 overbore. A 4.080 ovebored 6.0 block is very rare.

stealth

Based on my friends' experiences, it is difficult to find a good and true CI block.

Pro Stock John

iTrader: (34)

A C5R block is in a class all it's own, it's a better block than a production LS1, LS6, 5.3, 6.0 or 4.8 block. Kurt Urban would be the best guy to expound on this, but it's a different metal alloy and it's also goes through a fancier hardening process.

If I were to try to build an low to mid 8 second car I would look at getting a C5R block.

CHRISPY

I think that is a great idea.

.030 over ironblock, 4.030 blower pistons and good rods, good bolts/studs with stock crank.

high flowing heads (2.08/1.60 valves)

Blower cam (236/242 on 114 or so)

Wouldn't be too expensive at all for the motor.

Then...

custom steel bracket and F series blower

Giant front mount intercooler

Sumped tank and full fuel system

Some sort of engine management software.

good gas and tune

Pro Stock John

iTrader: (34)

Gordon what's the lastest on your car, you have an F1 on there now?

1point3liter

Someone already answered this, but rotaries have 2.5 combustion cycles per revolution. your 1.3 liter is more like 3.2liter or so. a 2.0 liter 3 rotor is more like a 5 liter. Rotaries also produce a lot hotter exhaust gasses. The love turbos. You are comparing apples and oranges here.

A v8 requires 8 exhaust runners, and a lot more plumbing. The rotary turbo kits are simple and don't include an intercooler. A greddy t-78 turbo kit sells for $2800 at most dealers cost (means you got a smoking good deal). By the time you add a $1000+ dollar intercooler you're already up to about $4000 and still need a blow off valve etc. I don't really see how quality rotary turbo kits are that much cheaper.

Rotary's also only need 4 fuel injectors. (less cost when it comes to fuel systems)

Yes, Meth, alcohol, and water injection are utlizied on some setups. Some people have made a lot of power relieing on these systems.

I'm at work and don't have time.. but it isn't that hard to calculate if you look up the specs on a ls1.

I will agree here. Many of the LS1 enthusiasts are stuck on LS1edit. Imo, it sucks and I'm planning to run an AEM or FJO stand alone.

Some people run FAST etc... So yes enginemanagement is being used, just not as commonly as in the rotary world.

If you make a good kit cheap enough.. I'm sure people will buy it.

INSOMNIAC

I have been advised by bunch of people that block is not the way to go cheap if you are building a moster RWHP machine. So, I guess I should go with a C5-R block then. Bored to 4.125 with a 4.000 stroke.

Do you pick the piston bore size slightly larger than block bore size? Why dished pistons on supercharged cars? Can I order custom Lunati pistons? How do I know how much -cc? Do they thermal coat these pistons? How do I determine my compression ratio? I am thinking of 9.0:1 with 16 pounds of boost at 6000 rpm. Does that make sense? Centrifugal supercharger works linear to engine speed. But is there a way to keep 14-16 pounds of boost from 4000 to 6500 rpm? How much boost will I be making at 2000 rpm? All this is with a F1-R blower.

Does anybody have contact info for Lunati? I guess I should give them a call.

Wow, I just asked you guys a ton of questions. But I'm getting good replies and info. Thanks for all the input.

1point3liter

Seems like you're fishing.. maybe you better stop by the fishing shop for a better lure.

Just out of curiousity.. why are you considering a pushrod v8 if you're making such great numbers?

I'd ask you more about your turbo rotary setup (sounds like you're using two power adders), but I feel this is already border line hi-jacking (just helping to defend the LS1 peeps).


anyways... back to our regularly scheduled program.

Wet 1

iTrader: (4)

Any reason why no one has mentioned a screw type SC w/ aftercooler for this application? Don't they make one? They fit on the vette's with a slightly modded hood... correct? I don't know much about these systems on your engines, but I know I don't care for the centrifugal style because the boost build in a linear manor with RPM. I know many on here keep saying use a centrifugal SC... yes they will make the big number, but other methods offer way more power at lower RPM's which is more usable power IMO while still being able to reach your HP requirement. I'd gladly pay a little more for a FI system that made full boost at lower RPM's, rather than the centrifugal types which only make the # at peak RPM.

Just my 3 cents.

CHRISPY

Never get enough boost out of the current kits (pulley limitations).

Hard to go over 8# on a stock bottom end with one.

Evil F1 SS

I had the F1 on the car and we had bracket flex problems that would lead to belt failure. I sent the F1 to Procharger to get a standard spining f1 blower and am having custom brakets made(I can run a wider belt now). I had to delete the power steering and relocate the ALT. we are also doing the griffin FMIC at the same time.

Evil F1 SS

There is no Twin Screw blower for a Corvette. There is a M112 roots non intercooled blower (same junk thats on a 03 Cobra) Starr performance makes one for the GTO that could support 800 rwhp. they use a 3.3L Intercooled whipple with a 95 mm TB and intercooler set up. The accs. drive on the GTO is the same as on a vette so im sure you could get one to work with a vette. The 3.3L w/ intercooler would require a much higher cowl hood than the magnussun. GTO owners have to cut the hood to get the 3.3 L to fit. the 2.3 L will fit under a stock GTO hood.

No one is familiar with the MAF delete that the ausies are using to tune LS1 cars past the 800 rwhp mark?

Wet 1

iTrader: (4)

Why is that, are the units undersized for the application?