CalSpeedPerformance

iTrader: (64)

Im looking to put together a new combo for my LSx powered fox stang with the S-91 ive got. Goal would be 8.50 as thats as fast as the car can go without going under major surgery to make it a 25.5/25.2 car and I dont want to do with that to it since its a street car. The car will be at a 3250 race weight, which is pretty light.

Ive got a new LSx block in the crate sitting here and trying to decide what way to put it together...either all out or budget. I think I can build a mid-8 sec daily drivable setup pretty cheaply if I put my mind to it. I already have the BS3 efi, 96lb injectors, complete turbo setup and all the other small parts/misc. Just need the longblock finished.

I've still never seen anyone have much of a problem with 1000-1200 rwhp on a stock crankshaft and I want to run the TFS 245cc LSx 6-bolt heads (I can get new for $2300 setup ready to go).

Before I started ordering parts, I figured i'd throw it out there.

396" Cube LSx Shortblock Plan at the moment:
LSx Engine Block Own
3.622" Stock Crankshaft (prep) Own
6.125" rods /w arp2000 bolts $475
4.175" Wiseco Pistons /w rings $750
Rod/Main Bearings/Rod $175
Machine Work/Assembly $1,100
ARP Main Studs $188

Total: $2688

Remaining Topend:
TFS 6-bolt Cylinder Heads $2300
MLS Head gaskets $220
ARP Head Studs 6-bolt $360
7.4" ChromeMoly Pushrods Own
melling 10296 oil pump $125
LS7 Lifters $125
Rollmaster Double Chain $125
Custom Camshaft $340
Stock Rockers Own
LS2 or LS6 Intake Manifold Own
90MM TB or stock ported Own

Total: $3595
Grand Total: $6283 for complete engine



I'd love to hear anyones thoughts/opinions or ideas if you see any flaws in the build.

bluecamaroz28

If you go TFS heads, stock rocker will not work.

trey04gto

iTrader: (4)

props on trying to do a budget build!!! But... I would not use the stock crank and get your cubes from such a large bore. most of the better engine builders will tell you even on the LSX blocks in cases of large boost numbers ie that from a S91 to just go 408ci with it via 4.030 bore and 4.00 crank. maybe 427ci with more crank and a little more bore. my 2 cents.

CalSpeedPerformance

iTrader: (64)

Oh really... I hadnt heard/seen that. I have a set of yella terra ultra-lights I can put on it if needed.

Pro Stock John

iTrader: (34)

I ran HS rockers in the h/c/n20 Camaro with TFS 215's.

I would probably run the same rockers with the 6 bolt TFS heads that I just got.

I think you should just take the block out to 4.030, treat it like a BBC. You want to leave some material in case you have to redo it at some point.

Jake@EPP

Id throw a aftermarket crank in there just for the saftey net, sure the stocker works, but if it snaps or something happens, not only are you out a crank, but a block/rods/....


I understand you want to save some money, but going 8 seconds and being cheap have nothing in common.

Like they say, Cheap Fast Reliable, pick 2 of them and it aint the other.

bluecamaroz28

Better leave some meat in the block and get a 4.0" crank for added safety.

With TFS, you must use roller rockers.

black98ws6ta

iTrader: (77)

I like your thinking alot! I am doing something similar, and not going to hesitate to use the stock crank. I would also go smaller bore for a future rebuild.

BLWN1

iTrader: (6)

Do you have a LSx block with your stock crank....^

CalSpeedPerformance

iTrader: (64)

Phil's mustang runs 4.175" bore with 2000hp in his LSx block and he is still turning it up. His car has went 191mph and im looking to make half of the horsepower, so I'm thinking ill run 4.155" which leaves .020-.030 for a rebuild.

Mr.MartyStone

iTrader: (12)

Yeah but he's also running a crank that doesn't look like a jumprope at any decent RPM. I would chit chat with Erik Koenig about the build, 4.150" is probably the most I'd go to keep some meat on the walls.

trey04gto

iTrader: (4)

listen to some of these people man. Alot of intelligent, experienced folks on here. Talk to Erik Koenig as listed above or LME maybe. They build Steven Feredays motors which just happen to be.... a 408ci LSX motor with no expense spared. He has gone 7.57 on his 408 LSX with a 106mm precision. He is now testing/running a 114mm.

Pro Stock John

iTrader: (34)

Sounds like Phil is looking for a stronger crank:

http://www.yellowbullet.com/forum/sh...ad.php?t=76202

CalSpeedPerformance

iTrader: (64)

One think I'm noticing...is all the builds you see with 6.0's (370") almost all use stock cranks and you rarely see anyone recommending a crankshaft upgrade for 1000 rwhp applications with 346-370" motors.

Im not trying to be stubborn, its just that I havent seen anyone break a LS1 crankshaft due to too much horsepower. With doweled main caps on the LSx you wont see any main cap walk etc but I know there is concern with crank flex. I think if i was going to turn it up about 1000 rwhp i would step up.

Another thing im thinking about that relates to crank strength:
Torque is main cause of a crankshaft failure, not horsepower. RPM isnt much of an issue like it is with a connecting rod. Basically without the stroke in the motor, its not going to see huge torque numbers like with a 4.0" stroke etc.
Examples of high horsepower LSx setups running 800-1000 rwhp and no problems on the stock crankshaft.

Examples of success on stock crank with the power numbers im looking for:
pro stock john 870 rwhp , 144mph traps
mightymouse: 1000 rwhp, 155 mph traps
harlan 1000+ rwhp, 170+ mph traps...
Ohio boys, 8.6 @ 160+ Ls2 setup, 1000+ rwhp

My budget also includes just standard eagle h-beam rods and a shelf forged piston with standard wrist pins. If I was going to aim my goals over 1000 rwhp it would cost an additional $400 in rods, $800-1500 crankshaft, $250-$400 in custom pistons with tool steel pins, custom ring stack, coated etc, carb style intake/elbow/90mm+ TB/ETP LS7 heads etc ($2500 more), better converter, stronger powerglide swap instead of th400 etc. Im trying to stick to my guns and keep it very budget oriented and I only have the LSx block because I traded an rough old 2nd gen RX7 car for it.

Basically I would spend another $10,000 in parts to have a solid setup that would live with that horsepower.

Im not seeing any examples of people with "I had a stock crankshaft fail on a 1000+ rwhp setup". Only the suggestions that "its not a great idea to do it.

If I planned on running a 100mm+ turbo, I would step up to a 4.0" stroke. But Im thinking I can get alot more power out of this S-91 if I stay with the smaller inch motor. Jose @ FI has told me 440" motor (4.0" stroke) is going to run the S-91 really early and would suggest a bigger turbo for it.

Any more facts/details anyone has to share?

black98ws6ta

iTrader: (77)

I agree with what you have typed above. I pay attention to people who push the stock cranks, and how they look when they come apart, and for your budget I think it is a good decision. I would still go with a smaller bore. I dont see the cubic inches you gain in the bore being worth losing strength and rebuildability of your $2000 block.

trey04gto

iTrader: (4)

Very well stated SoCal. I get where you are going and the mindset for your build. I agree with the above post still though. Smaller bore and try the stock crank. Later you can still have plenty wall thickness left and then go to a stroker crank.