[BENT8]

Hey all im looking for some opinions, as some of you would no from my previous questions i was going to procharge my current roots SBC combo but i dont think it will cut it in the class i wanna run here. So i have bit the bullet and im going to start again

I have started piecing togther a combo that i think will kick ass and i just wanna run it by you guys and see if you think it will make the HP that i think it will.

SBC 4.200 bore with a 3.800 stroke
6inch rods
10.5:1 comp
Brodix CNC BD 2300 heads
Brodix BM102 manifold
ACCEL 2600cfm throttle body
Morris 4500 pro hat
Moran injectors
fuel will be methanol
As far as a camshaft is concerned i will be ordering that from Steve Morris.

Now i wanna use a F2 reverse drive unit spinning it to the moon, as in the class i will run in currently allow any size procharger but im damn sure that will change in the near future to be F2 only.


Now what do you guys think ? I think it will make an easy 1500hp and the power will be limited by the F2.

 

[sbc_racer]

i think wa might wanna keep crank at 3.75 to get a good piston in it as rules cant run iron eagle block

 

[ASH]

http://www.racerpro.com.au/13_deg_head.shtml

 

[dennysavage]

i think wa might wanna keep crank at 3.75 to get a good piston in it as rules cant run iron eagle block

I would also think twice about that 4.200 bore.... Not necessary, and you'll play hell keepin head gskts in it, even with the F2... Dont underestimate the F2...
I've got a friend that I help, with a 358" SBC, with an F2 that makes 1000HP at the rear...

 

[blwncrewchief]

Not much of a sb guy but just a few thoughts.

If your not limited to a f2 by the rules I would do a f3/117 or 123 and run what you need to and hope they don't change the rules Then you can step it up when you need to

4.200 is too much bore

10.5 is low for methanol unless you are going to run 50+ psi. I would go 11.5 - 12 for 30-40 psi. 11.5 at 40 psi still has a very reasonable tunning window.

Talk to a good piston company about what you need for a good piston design for your application then pick the stroke/rods based on that.

The best advise for methanol is lots of fuel and lots of fire power.

 

[morris]

I agree with everyone else here.
I would also put it on a 3.750 stroke and a 4.125 bore at biggest.
I would also think of pushing the rules to let you use that 123 F3 with a inlet reducer if need be later down the road. You will break the F2 at some point the F3 you wont.
Easy power

 

[sbc_racer]

inlet reducer thats a good idea makes me feel better as im in same class an have an F3R 131 allready

 

[mitro67]

I agree with everyone else here.
I would also put it on a 3.750 stroke and a 4.125 bore at biggest.
I would also think of pushing the rules to let you use that 123 F3 with a inlet reducer if need be later down the road. You will break the F2 at some point the F3 you wont.
Easy power

there has been some other series that have required a reducer and it didnt slow the cars down much or at all...

f2's can make 1800 hp on a small block.. chris groves runs psca wild street.. 410" ish sbf with tfs high ports(i think) f2 went 7.66 et in a stock suspended 3200lb mustang on a 275 m/t radial.. also look at the crank drive setup vs the belt drive... alot of guys running the crank drive havent hurt their head units as much.. and 2 bov's... my buddy hurt his f2 trans several times from peddling the car.. (small tire stock susp) two procharger bov's is what alot of guys are saying will eliminate this... or One Vortech mondo BOV.

 

[sle383]

Hey all im looking for some opinions, as some of you would no from my previous questions i was going to procharge my current roots SBC combo but i dont think it will cut it in the class i wanna run here. So i have bit the bullet and im going to start again

I have started piecing togther a combo that i think will kick ass and i just wanna run it by you guys and see if you think it will make the HP that i think it will.

SBC 4.200 bore with a 3.800 stroke
6inch rods
10.5:1 comp
Brodix CNC BD 2300 heads
Brodix BM102 manifold
ACCEL 2600cfm throttle body
Morris 4500 pro hat
Moran injectors
fuel will be methanol
As far as a camshaft is concerned i will be ordering that from Steve Morris.

Now i wanna use a F2 reverse drive unit spinning it to the moon, as in the class i will run in currently allow any size procharger but im damn sure that will change in the near future to be F2 only.


Now what do you guys think ? I think it will make an easy 1500hp and the power will be limited by the F2.

good luck with the new combo mate.

 

[ProchargedNova]

Not much of a sb guy but just a few thoughts.

If your not limited to a f2 by the rules I would do a f3/117 or 123 and run what you need to and hope they don't change the rules Then you can step it up when you need to

4.200 is too much bore

10.5 is low for methanol unless you are going to run 50+ psi. I would go 11.5 - 12 for 30-40 psi. 11.5 at 40 psi still has a very reasonable tunning window.

Talk to a good piston company about what you need for a good piston design for your application then pick the stroke/rods based on that.

The best advise for methanol is lots of fuel and lots of fire power.

Why do you think the 4.200" bore is to much? I'm running an F2 sbc now with a 15* head and 4.155 bore on gasoline and plan on changing to the BD 2000 and methanol with an F3. I was recomended to go as big a bore as possible to help unshroud the valves. Is 12:1 common on alky at around 35 lbs of boost?

 

[BENT8]

Thanks for the help guys, im wondering too what the problem with the 4.200 bore is ? Is it more a headgasket thing or just cylinder wall problems.

 

[Blownbird]

Thanks for the help guys, im wondering too what the problem with the 4.200 bore is ? Is it more a headgasket thing or just cylinder wall problems.

Keep the Cylinder walls as thick as possible, you will have incredible cylinder pressure. Valve shrouding is not going to hurt it like it would on a N/A combo, especially with 20+ psi on the back of the valve.
DonB.

 

[blwncrewchief]

Why do you think the 4.200" bore is to much? I'm running an F2 sbc now with a 15* head and 4.155 bore on gasoline and plan on changing to the BD 2000 and methanol with an F3. I was recomended to go as big a bore as possible to help unshroud the valves. Is 12:1 common on alky at around 35 lbs of boost?

I have found in general at some point with a max effort, boosted methanol engine the head gasket sealing and keeping the cylinders stable will become an issue. Parts strength also becomes an issue in a max effort combo. That is one of the main reasons all the high hp blown alky stuff is all solid billet blocks and heads. A sb with a big bore water block and water heads will run out of strength before you run out of power making ability on methanol.

Think of it this way, a screw blown or turbo 500ish ci engine can make 3500+hp on methanol. That is in the neighborhood of 7hp per ci. If you build a 400ci engine can your parts, block, heads, and head gaskets take 2800hp? That's why I would not do anything close to a 4.200 bore on a 4.400 bore space block on a high boost/methanol setup.

Static compression ratio is just a number and many other things play into it. In general I like to see about 11.5 in that boost range. If the cam doesn't bleed allot of cylinder pressure 12 might start getting a little narrow tunning window around 40 psi. I know people that have run around 13 with those boost levels, I just don't like running stuff that far out on the edge. But, I'm pretty conservative and don't like hurting stuff. Just my opinion.