JE forged pistons w/ proper rings, eagle 4340 forged rods, & a studded 4-bolt block.
would a 3.75 scat crank handle that?

 

They have before but nothing is a "for sure" thing. Will it break the first time or the three hundreth time? No one knows. Kinda like that ol tootsie-roll pop commercial.... "How many licks does it take..." lol.
And Scat makes both a cast and a forged crank... which are you planning to get. I've only personally seen 3 crank failures in my life and it's always tough to tell if it was due to shock, poor build tolerances, a spun bearing, improper press fit with the dampener, or maybe all of the above........... maybe something not mentioned...... maybe none of the above. Too many variables.

-Mindgame

 

TTT

 

Since you aren't getting much in the way of response, I'll try to stimulate a little thought.

Are the pistons specifically designed for a large shot of juice? Are they "nitrous" pistons? Is the top designed for the requisite strength? Has cooling been addressed by moving the heat correctly away from vital parts? Have the rings been placed further down on the barrel?

What rod length are you using, and what did you do about the placement of the wrist pin in the piston?

What rings are you planning to use? Ring rails?

You definitely need a forged crank to support what is probably going to be a 750-800HP engine. Can we assume you are talking about a SCAT forged crank - see question in first response, which you didn't answer.

 

As Fred implied, nitrous pistons are heavy. I am using the JE nitrous pistons and they weigh ~500gms w/o rings. You will need hella strong rods, bolts, and crank to spin these heavy suckers at 7K+! Which Scat crank are you referring to?

Rich Krause

 

thx for the replies Fred & Rich, i put a lot of value on the opinions of you both.

i was referring to the cast version of the scat cranks.

maybe i should ask my question like this, i'm looking for guidelines to build a budget 383. my starting point is a bone stock set of LT1 heads that i'll have upgraded to what they need to support a daily driven 383 with a compatible shot of nitrous. i want my car to be capable of road trips also. its a 93 M6 that will have Hooker LT's & 4.10 or so 12-bolt.
my goal is to have as much streetable torque & horsepower as i can without breaking the bank. i don't want to limit myself to a budget, because i'll locate an LT1 block to build while i still drive my car as is.
i'm more interested in horsepower per dollar.

questions-what exactly to have done to the heads.

2-bolt block with studs or 4-bolt with studs

i'll most likely use the cast scat crank since the 3.875 stroke runs much higher in $$ with minimal horsepower gains.

rods?

pistons?

rings?

and probably a 306, similar XE grind,or maybe even a solid roller cam if the bang for buck is a favorable ratio.

how big of a shot of nitrous?

thx again guys

 

Now you've really lost me.

The issue with "cast" is whether it will support the HP you are talking about. A decent economy buildup on a 383 should be able to net at least 450-475 flywheel HP. Add a 250- or a 300-shot to that, and you are going to be outside the limits of the cast crank. I would guess that it wouldn't want to see more than about 550-600HP. If you want to use a cast crank, you will either have to limit the RPM potential of the engine, and/or cut back on the nitrous.

Same with the block... a 2-bolt block is fine up to similar HP levels, but once you talk about spraying 250- or 300-, I would want the security of the 4-bolt setup.

I'd say maybe drop the nitrous completely... it will only complicate things, increase cost, and reduce the power potential of the N/A setup. Use a 2-bolt block, cast crank, some prepped PM rods and a set of upgraded hypereutectic pistons, and you have an economy stroker. Put the $$$ into the heads, getting as much flow as you can, and then select a cam to match, recognizing your limits of "streetability".

 

here is what My cast crank,stock worked rods, and KB hyper slugs take.... its a 355 with a .600/.600 242/250 solid roller ,aluminum Trick flow heads,jr intake. It has made at this point 30-35 passes shifting at 6800 to 7000(a few on a 150 plate) and im guessing 2000 or so hard street miles and its still running. I know that its not going to last forever but I was on a budget and wanted to go a little faster.

I know that im pushing it past its intended limits but its worked so far.

Good luck
Ray

Its dipped in the 10's on the gas and low 11's natural in a 78 camaro. I think its ok for a bucket of spare/barrowed/scrimped parts.

 

Now i dont know nearly as much as all you guys do, and i am still learning. but as far as i have seen, i have never read a whole lot on engine malfunction/failure due DIRECTLY to a crank. i have seen some people run very nice numbers on cast cranks (granted not alot of 700-800 hp). how many times have you fellas seen a screwup due to the crank not being able to handle the power (RPMs i would have to agree tho). Just as one example, IF i have read correctly, IF, in one of the latest summit catalogue, "Fast Eddie" Parker who has the "Fastest Street Car In America" is running a 632 cube 1140 hp/960 tq BB and he is reportedly running a Cullys steel crank and a 350 shot of giggles(of course he cant rev this to the moon). am i totally off basis? what have i not taken into affect...school me....in my unprofessional opinion it could be done if you lower the rev limit and stay with a cast crank

Paul (c:

 

What is your question? If Parker is running a "Callies" (???) steel crank, it is most likely a 4340 forged piece - not a cast crank. Or did I miss the point?

 

O.k.

How much N2O? A 200 shot on the right bottom end will be fine.

First yes you can run a Scat 9000 Series on Juice, but over 550hp it's not a good idea. That means that you are looking at a good 500hp 383 with a 50 shot on it, It's worth more to buy the better heads and go from there.

Spend the $700 on the 4340 crank and go from there. You already need $400-$500 rods for N2O, and $400-$600 pistons because you are doing forged units.

If you want a N2O cam it's much different than a NA cam. Larger LSA, and more exhaust duration.

Bank for the buck is not a term you use with a street Solid roller. Esp. if you are going from a Hyd Roller to a Soild Roller, get a dam Rev kit and call it good.

I guess the next question is what is your budget? That really will tell you how much power you want to make.

Bret

 

Not saying I haven't been lucky, but this is what I'm running:
383ci
Scat Cast 3.75 crank
Stock Rods - ARP bolts
KB -16cc pistons
2 bolt block - ARP bolts
CC306 cam
ARE STG2 Heads
175hp N2O

Has been to 6800 a couple times on N2O, was shifting 6400-6500 rpm NA, but try to stay around 6200-6400 now on N2O.

This'll be the 5th year for the shortblock and the 3rd year on the juice. As I said at the start, no guarantees this combo will last. I wouldn't do it again, but I had no idea I was going to do this to my car either!

 

My approach was to bite the bullet and put the parts in up front:

381ci
10.8:1
Callies Stealth 4340 forged 3.75 crank
Oliver 5.85" billet rods
BME custom nitrous pistons
Pro-Gram splayed 4-bolt conversion - ARP bolts
CC solid roller, 230/242 114 0.590/0.590
CNC LT4 Heads
300hp N2O

I spray from 5,000 to the 7,000rpm nitrous cutoff, and the rev limiter is set at 7,200rpm. Total output on the spray is approaching 800HP flywheel. Most of the runs to date are limited to a 125-shot, but it has dyno'd several times with the 300-shot. Hopefully I'll get a few 300 passes on it this year.

The parts were expensive, but I figure I shouldn't break anything, and won't have to buy anything more expensive in the future, assuming I want to push it a little further.

 

Could it work? Sure, we all know someone who… I know someone that ran roughly 900hp through a stock cast crank and modified stock block in a vette (148mph at the track with no traction) for 3 seasons and never had a problem with the crank/block (couldn’t keep gaskets and pistons in the engine to save his life). I don’t think that anyone would call it a reliable setup or recommend it.

You’re asking for conflicting things: 300hp n2o, 7000rpm long stroke engine, reliable street car good for road trips, cast parts… If you’re asking “what setup can I build that I could drive to an event, spray 300hp N2O through and drive home” I’ll say there isn’t one. At some point it will leave you stranded probably a few times a season. You will break something (not necessarily the engine if you build and maintain it right). If you want something that fast and to take it places plan on spending money on a trailer and tow vehicle.

Unless you consider the engine a disposable piece I’d suggest using good parts (something along Injuneer’s list is a pretty good way to go), because if you don’t something will eventually go taking other parts with it.

WRT to making a truly reliable setup I’d suggest some combination of:
- less N2O (N2O pounds rod and main bearings)
- forged parts
- less RPM (rpm breaks parts more reliably then excessive hp)
- shorter stroke (stroke increases piston speed which has a similar effect to increasing rpm)

 

Not a Callies, its says hes running a Cullys steel crank, hessays nothing about forged except the pistons. and my question was how many people have heard of failures due directly to a CAST crank giving up (granted it wasnt revved to high)? no flame, just a question...