Offroad engine selection. 1200-1300HP, reliable.

[Keith Morganstein]

What is the duty cycle? Time at max HP? Average HP output?
What can the engine package weigh?

[viper]

I will try to better explain. The figures targeted were "optimistic" but I have realized are probably not realistic. When I say 500hrs, I mean fatigue life of rods and crank and possibly the heads. Even that might be off the rocker. Typical might might 100hrs running at mostly 50% power. Duration of race can be 12hrs or more. The extra power is only for short burst acceleration only.

Actual weight of the engine would be best at 500lbs but give or take a bit will not be a huge issue.

This is endurance racing in an open class so very few rules other than finish the race.

The LS7 is making about 800hp and we have used them as turnkey but would like a little more accel when needed. vehicle weight is about 4500.

I do own a machine shop but we are not an engine shop so some of this build work will have to be outsourced.

Not to pick the pepper out of the fly shit but roots and twin screw are different. Twin screw is internal compression and runs much better efficiency. I intended to use a liquid to air intercooler. Pos displacement is ideal due to the instant power, no lag. I realize turbo would be much better to get the HP target. However, again, I realize I might have to 'ask' for 1300hp but settle for 1000hp. I know that torque is what will likely be the winner here. Being able to grunt out max torque at 3k rpm is something only a pos disp blower can do IMO.

I do like the Viper V10 platform but that will be very spendy. If I can find a way to stroke or otherwise squeeze a little more from am LS7 or similar, it might work. Hell, just intercooling might be a solid advance here.

I seem to remember Kenny Bell pulling some ridiculous numbers from an LS7 on pump but I also realize that could really bite us with engine life too!

Mostly just looking for ideas here guys. Turbo diesel is just not realistic. Turbine is not realistic. Guys are running peepee out of the LS7 at 800hp. I would just like to get a little advantage. Just doing some brainstorming here.

[Notchback]

This reminds me of a few Ty Lofstrom builds. Well educated, possibly lacking in experience in the particular topic. Has Read both of Corky Bell's Forced induction books. I will be interested to see where this goes.

[66Vette]

Not sure why the big block chevy is not getting more consideration. It is not that much larger than a small block and weight can be trimmed down in the 500 lbs range with aluminum head, intake, and other diet pieces. Push a low deck block out to close to 600 CI and you can have 800HP NA……easy. Add in a power adder of choice and your 1200 HP is well within reach.

Here is a low deck BBC at 1000 HP NA from Shafiroff:

http://www.ultrastreet.net/engines/598_bigdawg_sr20.php

[viper]

I appreciate the reply and quite possibly something we are considering. BBC was mostly taken off the list in hopes that the SBC could fit the build but hell, if we are looking at the Viper V10, the BBC might be the best move here. Even at 1000HP NA, that knocks the snot out of the budget and complexity not needing the blower, IC, etc.

What block are you thinking of as the donor? I'll admit, the pricing anymore for bare blocks is getting insane! The the point we could damn near machine a solid billet block cheaper than buying a casted one!

On the heads, I intended to select a good "bench mark" head and rework them from there and go ahead and port our own via 4 axis and blend things by hand. Can get about 90% with 4 axis. I probably mentioned we have a machine shop, flow bench, and I have been porting engines for a day or two. I just have to look at the impending grenade! Not if, but when...


Hell, I wear the T shirt "no replacement for displacement"

[66Vette]

Dart Big M. For a price point, here's what Shafiroff sells a 598CI short block for:

http://www.ultrastreet.net/shortblocks/ ... owdeck.php

Your goal of $15K looks pretty reasonable if you do head work and all the assembly. Of course you could go tall deck and push the displacement even further, but that is another step up in size, weight, cost etc.

[viper]

Price looks reasonable for that short block but I might question the guts on that one. Has to be cheaping out somewhere.

I would really rather select my own guts and find a good source for a bare block? I'll admit that for that price, I would probably come out ahead to just sell the guts and rebuild the short block. Use to be able to get bare blocks for 1500 bucks or less! Now you pay extra because a bigger hole costs more! lol


Also, if we decide to boost the engine, I would need different pistons anyway.

[wyrmrider]

sbc is not going to have the durability you desire at anything near your desired power level and rebuild times
look at the bearing widths, crank pin overlap, etc

[Keith Morganstein]

Price looks reasonable for that short block but I might question the guts on that one. Has to be cheaping out somewhere.

I would really rather select my own guts and find a good source for a bare block? I'll admit that for that price, I would probably come out ahead to just sell the guts and rebuild the short block. Use to be able to get bare blocks for 1500 bucks or less! Now you pay extra because a bigger hole costs more! lol

Also, if we decide to boost the engine, I would need different pistons anyway.

Here is a low deck BBC at 1000 HP NA from Shafiroff:
http://www.ultrastreet.net/engines/598_bigdawg_sr20.php

He's not cheeping out, it's a street engine. Scats import 4340 crank and h-beam rods. Its not a racing endurance engine. You need a Callies magnum or Crower crank, Oliver rods. He'll build you whatever you want.

They buy cheaper than than you can, they have all the machining equipment and experience. Hard to beat a block and rotating assy package from a reputable builder unless you can do all the machining.

A big M billet cap block, all machined (through a blueprint shop), to your specs is around $3000. Add the cost of the balanced rotating assy and the related parts for assembly.

Some want the satisfaction of assembling the engines and are proficient at it. More power to them, but they don't always save cash.

540 cu is probably enough with a centrifugal supercharger.

[Keith Morganstein]

Mostly just looking for ideas here guys. Turbo diesel is just not realistic. Turbine is not realistic. Guys are running peepee out of the LS7 at 800hp. I would just like to get a little advantage. Just doing some brainstorming here.

Finally we get the picture. You want more than an 800hp LS7. You were asking for a 400-500HP advantage...not so little.

IMHO, if the LS7 is living, its not at the higher horsepower levels very much of the time...

[justahoby]

Something like a turbocharged BBC on Methanol in a New Century block or do a hemi. EFI. Bring your check book and a few extra pens. A v16 Silver 92 Detroit would meet the power and durability goals but packaging could be an issue.



The off idle torque will be a noticeable increase from your basic warmed over 350.

I was going to be smarta$$ earlier also..
http://www.fordgaaengine.com/index.html
Friends I bring you 1100 cubic in all aluminum tank engine .. Over 1000 ft lbs of tourque at 2800 rpm .. Many people reliably removed the governor and ran them a constant 3000+ rpm .. In a V8.. Still large lol

[redcorvette]

This would meet almost all of the requirements.
http://www.automotix.net/usedengines/bu ... ntory.html

[viper]

He's not cheeping out, it's a street engine. Scats import 4340 crank and h-beam rods. Its not a racing endurance engine. You need a Callies magnum or Crower crank, Oliver rods. He'll build you whatever you want.

They buy cheaper than than you can, they have all the machining equipment and experience. Hard to beat a block and rotating assy package from a reputable builder unless you can do all the machining.

A big M billet cap block, all machined (through a blueprint shop), to your specs is around $3000. Add the cost of the balanced rotating assy and the related parts for assembly.

Some want the satisfaction of assembling the engines and are proficient at it. More power to them, but they don't always save cash.

540 cu is probably enough with a centrifugal supercharger.

I am certainly not in the business of wasting my time just to say "I assembled it". I don't have anything I need to prove to anyone. However, this is not just about building "an engine", this is more of "an engine program" so we will need to have a few and constantly opening them. In the sake of both time and cost, it might work in our favor to do some of the work. We don't have line hones or crank grinders or anything here by my local guy is good, fast, and cheap. If I tell him to take .0023 off the crank journals, I will get just that.

I do hear you on qty sales on parts and it might be cheaper to just start with someone building us the short block and we can work it from there. All just going to be a numbers game but I would need to decide on a block config. I am not sure how the Pontiac stuff compares to the short deck BBC. I also don't want to step too far off in "custom build" territory which just means expensive. I like smartly matched off-the-shelf goodies.

[wyrmrider]

http://richardmoser.com/Images/Torq.pdf

[PackardV8]

The Moser V12 spec sheet gives 50 or 75 hour warranty. The OP requires a 500-hour durability.