Vette beater

the first day i had my car and i spun a bearing, thats what i get for buying a pre modded car...since im most likely going to have to replace the crank, i would like opinions on wether or not to get a stroker. how many of you would or wouldnt and how much power gain would i get out of a 383 stroker? assuming it already has a mild cam, and full intake and exhaust.

TurboLark

iTrader: (3)

Might as well. Just gonna cost a bit more. From what I have seen on here it will be around 25-50 hp and ft lbs better.

slowandrichws6

iTrader: (2)

sorry to hear that about your car. always remember that theres no replacement for displacement

donalr76

I have an LS2 403 and you gotta love the torque it makes you can get the HP with a stock crank, but it won't have that same grunt down low.

joker machine

That sucks, I would go for the stroker motor 402 or 408 tho. Like slowandrichws6 said no replacement for displacement.

landonew

It will cost almost as much to get a 383 stroker plus your blcok rebuilt, than it would to buy a forge 402 from a sponser. Could always just get the crank turned, and put new bearings in it. That is what i did. Sucks man, sorry about your car. Look at my sig, we are in the same boat.

SlowZ28/SS

iTrader: (14)

Stroke it all the way!!!

InchUp

iTrader: (2)

All else being equal, a short stroke engine and a long stroke engine will make about the same horsepower. The difference will be the long stroke engine makes horsepower at a lower rpm, which means it makes MORE torque. Same horsepower, more torque. The long stroke engine wins. Over-simplified, the airflow potential of the head determines horsepower, but the displacement determines rpm, and therefore, torque.

Stroke it, bore it then boost it. You'll have a monster on your hands.

blu byu EH

iTrader: (25)

That sucks (landonew and vette beater) i hope that **** don't happen to me when the install is done that would suck

landonew

This is true, but only marginally. You will see a lot of TQ gains on the bottom end, but there will also be marginal gain on the top end. But to stroke your ls1, you will need a rebuild ($1850) plus forged rotating assemble( $1750). This is just a $1500 dollars shy of a built 402 from lme or tsp. Why not spend the extra money and have a beast. Could prob sell your short block for 300-400. I would have done this, but i just decided to cheap out and have the crank turned and have new bolts/bearings installed. Hope this helps.

InchUp

iTrader: (2)

Marginally indeed. You'll see about a 15-20% increase in additional torque and horsepower from boring and stroking a motor, the real gains come from forced induction.

landonew

yea, but the kid has a spun bearing and is looking at building a reliable DD. Not a force fed track car! Not saying that FI is unrealiable, but it is a little hit and miss. ask any of the FI guys.

landonew

Do yourself a favor and have the shop or you if DYI check the bearings. Hell, just get some ARP rod bolts, and new bearings. Its cheap insurence. Good luck bud, and don't be pessimistic. I am sure your build will go better than mine.

InchUp

iTrader: (2)

You're hinting at it, but that's alright. I agree. Those who don't put the right controls on a forced induction system experience hit and miss results. Especially when they don't do enough R&D before hand.

landonew

Yea, I really don't know enough about it to argue the point. I do know that if you are going to do it, you should commit now and buy a purpose built boost motor. Im talking 8.5:1 compression, boost pistons... the works. I think the guys who have the most issues are the guys who Cheap out(cut corners) and the guys who decide to do FI on motors that are not built for them. For instance, you wouldn't want to just slap a procharger on my engine @ 13.5:1. Well actually, as it sits it probably wouldn't matter. Whats it gonna do, spin a bearing??? lol!

InchUp

iTrader: (2)

8.5:1 compression is most definitely not required. Neither is 8:1, 7:1, 9:1, 10:1...ect. There are many variables that go into determining ideal compression, static and dynamic. I invite you to buy and read the book "Maximum Boost" by Corkey Bell and learn the basics about turbocharging. It will be a good start down your road to learning the ins and outs of boosting a motor. Definitely read the book if you get the chance. We (enthusiasts) spend hundreds even thousands on our vehicles, yet surprisingly how many of us own even 2 or 3 technical pieces of literature at home? Magazines don't count. $20-30 spent on a book is well worth it.

landonew

Yea, I will be the first to admit that I am unsure about the ins and outs of FI. I know that most motors built for boost have lower compression. This allows them to run lower octane fuel and still maintain high boost levels. I guess you can go with more compression if you have meth/alky injection or run race gas. The point is to keep the tempurature of the A/F mixture below the critical temperature to avoid pre-ignition. The higher the compression, the greater the temperature increase during the compression cycle (simple ideal gas law, you compress a gas it's temperature rises). There is also temperature rise when you increase the amount of pressure to the engine at BDC. So basically, by having a lower compression motor you alot for the ability to have more boost while maintaining an overal temperature that is similar to the one prior to the increased boost. Am I on the right track? So, while nothing is "required", lower compression is advantageous in the respect that it allows you to run more boost without exceeding the critical temperature thus avoiding pre-ignition.

InchUp

iTrader: (2)

There is no such thing as the 'best' or 'ideal' compression ratio. The simple fundamentals are such that the lower the compression ratio, the easier it is to produce a lot of boost with no detonation, however on the other hand the higher the compression ratio, the greater the fuel efficiency and non-boosted throttle response. You are certainly on the right train of thought with the pesky gas laws associated with compressing a gas, like oxygen, when passed through a compressor (turbo or supercharger). You are also on the right track with trying to avoid detonation at all costs, however, as I said earlier there are more variables to play in that are more important. Such a variable is the added bennefit of being able to take that increased temperature charge out of the compressed air through means of a heat exchanger, or around here called an intercooler. Serious efforts with intercooling allow a builder to have their cake and eat it too by being able to have a motor that is quick to respond while sacrificing no boost potential in the upper rev range where the compressor exceeds at doing its job. Such other variables include block and head material, cooling system of the engine, camshaft profile, octane fuel availability, spark plug heat range, advance/retardation of the timing, intercooler and compressor efficiency, amount of boost pressure, BOV's and finally electronic safety controls. I'm sure I have forgotten somethings but those are the basics I can remember off the top of my head.

I still encourage you to pick up the book. It's an enlightening read.

tillery

iTrader: (4)

then why dont you boost your V6? GNs adn some supercharged Grand Prixs dont suck that bad and they are a 3.8 liter

InchUp

iTrader: (2)

Simple answer: Money and reliability. It is cheaper for me to swap in a 6.0L V8 that will last 100k+ miles than build up a boosted 4.3L to see the same 100k+ miles. Furthermore, a sport oriented motor is not what I'm after; in a truck such as mine I am in need of low end torque with good gas mileage.

If you'd like the complex answer PM me. I don't want to continue to hijack Vette beater's thread anymore than we already have.