4.1 stroker kit still a go?

[Timbo1969]

Originally posted by DARK SDE '02:
Eh this is of no use to the boost boys :( Higher compression = bad. How can it run mid 13s with only 240whp on a FWD car? LS1s have around 280-290rwhp and they only run mid 13s themselves. Something seems a bit off to me.

Well ask Zooomer how the car did it then.

As far as FI goes on the stroker kit, the reworked crank will only hold up to 375hp before it snaps, so I wouldn't try boosting it, to much. I guess if you really wanted to you could take the reworked crank to an Eagle dealer and have a forged one made identical to it. It'd probably cost you a ton of $$ though..

[Turbo V6 Camaro]

yes its weker becuase the take so much off the crank to lighten it, they broke it in half, have you ever heard on person break our crank, you would be better off keeping you crank stock and getting longer custom fordged rods and low c/r piston and i bet you would be at the same price with a better set up

[Arctc Wolf]

lightening the crank may have 2 happen to balance the whole assembly. here's another fact. cast parts weight more than forged because it takes more material to make them just as strong. this is why forged wheels weight less than cast. The new stroker kit, if it just adds stroke or if it adds broe also, will have to use a 3.65" stroke to make 4.1 liters. U'd have to take waaay too much material off of a stock crank's journals to up the stroke that much. the new stroker kit will have to come with a new crankshaft, and it's prolly forged. I have no idea what rod thength or piston compression height they plan on using to make the kit, nor do I know how far down the cylinder the piston will be at TDC. I know that a 3.8 bore and a 3.65 stroke equals a little more than 248 cubic inches, or close to 4.1 liters. I've tried 2 ask zoomer about the specs on the kit, and he's avoided telling me anything, probly cuz he think I'm out 2 copy his kit since I know what all the technical terms mean, and how all these measurements work together.

[T-Punk]

so with a properly tuned and built block it might be possible to get 400hp out of this? Do you ever plan on making a heavier duty kit for those of us who want to run Forced induction?

[Turbo V6 Camaro]

no the crank is NOT forged its a reworked stock crank that's all, you have to send yours back as a core

[Turbo V6 Camaro]

This is going to depend on how you setup the rest of the car. With a larger engine head flow and cam choice play a larger role in performance. This kit raises compression from 9.4 to 10.2, this should give about 2% more HP output. The 7% added displacement should give 7% more HP assuming the rest of the engine can support this. Those factors alone add up to 9% more output. The forged connecting rods are very light; the crank is also lightened from stock. Lighter parts mean a quicker reving engine and more HP. Another big advantage of stroking is the mechanical advantage the longer stroke has. The piston has more leverage to rotate the crankshaft. (An example of this would be like using a longer end wrench to break loose a stubborn nut.) This gives an engine better low end and mid-range response. Our L36 with the stroker kit dyno'd ~240WHP or roughly 20% more than any other engine in our Grand Prix FWD community. We have a lot of mods done and expect to further increase HP with some tuning. Even more impressive than the HP is the massive amount of low-end torque gained, it will totally change the way the car drives and feels.

How much do the components weigh?
L36 rod w/ bolts and bearing 674gm

Stroker rod w/ bearings and bolts 540gm
Stock crank 34 pounds
Stroker crank after balancing 32 pounds

Will it affect my gas mileage?
After the install you will have a larger engine. This means higher fuel consumption. With the added compression your engine will be more efficient which should bring mileage to standard levels. The camshaft you choose to run will determine economy much more than anything else.

Does it come with a warranty?
The kit is guaranteed against defects in craftsmanship for a period of 90 days. There is no guarantee against hard part failure. Please inspect all items before installing them in your engine. If you follow our instructions for intended use your engine should not give you any problems. If you choose to ignore our guidelines and run a 250 shot of nitrous to win a race we cannot and will not be held responsible. We can however assist by providing individual parts if later needed. To add a breakage warranty would raise the price of the kit considerably.

What am I actually buying here?
The basis for our kit is a reworked stock GM 3800 crank. This is why we charge a core. You're old crank will be modified, machined and sent out to another buyer. The rods are a forged connecting rod from another factory application. They have been shot peened, magnafluxed, and reworked for use in our kit. They have new bushings, new ARP bolts, and have been lightened and balanced to within .1 gram. The kit comes with modified Clevite rod bearings as well as Clevite main bearings and ARP assembly lube.

Why does the kit cost so much?
Adding up the bearings, rotating assembly balancing, custom rods, ARP bolts, crank work (which is expensive on our type of cranks) you'll see that we are right in line. Developing the kit took an investment and a risk. We had to spend a lot of money just to make a prototype engine. After that we had to dyno the motor and finally destroy it so that we could accurately report its limits. It is easier and cheaper to copy someone's work after they have proven the design and done the R&D but we feel this is not ethical and hope you feel the same way.

How can you balance the motor w/o the pistons or balancer?
We are balancing in a similar way that the factory does. All the crank pulleys, flex plates, rods, cranks, pistons, etc are nearly the same from the factory. They balance a setup and duplicate it. We take it a step further by individually balancing the rods to with .1 grams. We then balance a full rotating assembly using a stock L36 balancer and flex plate. In short, after installing the stroker kit your engine will be balanced better than when it was new from GM. If you wish to send in your parts and have any custom balancing done, we can do this for an extra charge.

What other parts do I need to make this work?
The kit itself allows you to build a 4.1 liter L36 but does not come with full engine rebuilding supplies. You will still need things like head gaskets, main bolts or studs, gaskets, oil, etc. We recommend our high volume oil kit with the use of 5w30 synthetic oil.

Do I have to prep the block in any special way?
Boring your engine over or doing other custom engine work will not affect the operation of this kit. No special clearancing or parts are needed. This kit changes the block deck height so if you are machining your block you will need to run a thicker head gasket. We recommend a head gasket between .062 and .070 assuming your block has not been decked. Please check all distances and clearances before assembling and running the engine.

Can I use nitrous and/or boost?


We tested in a boosted application and raised power until the motor failed. The engine ended up making ~375WHP and well over 400ft/lbs to the wheels before the crank snapped in half! The kits we are shipping now have some minor strength improvements from the original design but we do not recommend using nitrous or boost. The kit was designed for NA applications and therefore the parts are of minimal weight to maximize HP.


We do not know where the limits of these parts will be in your car. We can only provide you with the data that we have thus far collected. It appears that with boost in the range of 6-8 pounds you would be fine, but remember it's your choice. It stands to reason that if the boost is coming from a centrifugal blower you could run higher PSI than with a turbo or roots application. You should be able to run a small shot of nitrous, like 50HP, but be careful. Nitrous is very violent in the way it adds power and we would expect the parts to fail much sooner than with boost.

When will you have a kit for boosted/nitrous applications?
We are working on a few variations of this kit, which we may or may not sell separate parts for. Check the site often for more updates including complete engine packages.

Do I need to break in the engine?
Yes. You will need to use standard mineral oil at first and take it easy for 1000 miles. It works best to vary engine rpm and load. We recommend against going WOT until you have at least 500 miles on the new components. We recommend against racing the car until you have changed the oil and finished the break in period.

Will I get KR with compression this high?
If you did nothing else but install this kit we would guess that KR would be an issue. We recommend installing an aftermarket camshaft or running P&P heads. Either of these will eliminate any KR. On our test car we had a few degrees of KR when we tested with 87 octane. We were using an aftermarket cam and milled P&P heads. Compression ratio was 10.6:1

Why do my rods look like they don't match?
During the balancing process the rods have material taken off of them by hand. This means that each rod is going to look a little different. The cranks have handwork done to them also so each one is going to look a little different. Rest assured, every rod and crank have been checked for proper weight, lengths and specs.

What cam should I run?
After you have stroked your engine it will produce peak power at a lower rpm than before (assuming the same mods) You'll want a larger cam than normal with an LSA about 1-2 deg narrower than before.

Will I pass emissions?
Stroking your motor does not change emissions.

Do I need a custom PCM?
No, in fact because the stroker makes so much more low-end power raised shift points aren't as critical to performance. The increased stroke gives the car more vacuum at idle so it will idle smoother with the same size cam that might make a 3.8 run rough.

* NOTE: $100 Core charge, this money will be refunded when you send back your stock crankshaft with no spun bearing journals. We do not need any other parts back.

[Die Ford V8]

Ok, so I want more cubic inches but boring is minimal and the stroker kit wont work with a turbo with a decent amount of boost. Is there a "cheap" way to have a forged kit made. That sucks this think can only take 375 hp, which is only about 350 or less to be safe. Someone said just to get rods and different pistons but that still doesn't make it a "stoker" pistons still go up and down just as far. When they make a kit with a forged crank that will handle 500+ hp w/forced induction then I will buy the kit, but until then us turbo guys or wannabe turbo guys still have to stick with stock. :( :( :( :( :( :( :(

[Turbo V6 Camaro]

if you buy connecting rods that are longer then stock it pushes the piston up father and pulls it down more!!! go forged and you will be fine, but you will need custom pistons for the added stroke to bring the c/r donw to at least 9.0, high boost 8.0 or 8.5

[Arctc Wolf]

wrong viper, longer rods don't pull the piston down farther. the same stroke w/ longer rods will make the piston travel the same distance, but will add compression since it's decreasing TDC volume. Now that I read that post above, I'm really wondering if I wanna get the kit. Reworked stock crank, some kind of forged factory reworked rods, hmm... I'd feel safer w/ a forged crank down there. I'd think about cryo-treating the rods and crank b4 I put them in my car, just for a little added peace of mind for myself.

[firebird1]

remember when stroking a 3.8 seemed like a good idea? [img]graemlins/barf.gif[/img]

[Die Ford V8]

why did they to this with a stock crank when they knew it wouldn't hold up to any real amount of horsepower. these engines would only last 20,000 miles per crank at only 300 hp

[Die Ford V8]

is a l67 crank the same as an l36 but stronger???

same pistons too but stronger or???

sorry if this was already gone over

[Red94Camaro]

This is just my opinion, but you guys are better off just doing an LS1 or LT1 swap. I wouldn't spend that much on this kit. Then you have to pay for the engine work also. I didn't even spend 2k on my stroker kit and it will handle up to 700 hp easy. I would wait until a supercharger/turbo application is out then boost it. I wouldn't spend 2k then labor to gain 40 hp. An engine swap is the best thing to do with all that money.

[2002firebirdguy]

I agree with Red94. This is way too much money for the power you get. Do an LS1/LT1 swap and have way more hp. This kit is WAY to expensive based on the power gains. Not trying to rag on the guys that built it. It takes a lot to do something like this.

You could buy Tiago's turbo for 3k, have it installed, and have 270+ hp. Rather than this kit for 2k and 240hp.

Just stating the facts.

[Die Ford V8]

well said. if the kit goes for a little more than doing a non stroked forged kit maybe, but like you said, its fricken expensive.