Stroker MPG

[jason_alex_2009]

Alright guys I have done a little reading and right now i am getting 21 MPG on the high way with my 4.0 I am planning on a modified pore mans stroker IC944 pistons 4.0 rods scat crank and a stock cam, If the driving style dosnt change any idea how much my mileage will go down? I have heard numbers as low as 15 on highway... Most my driving is done in the city and since I drive only about 6 blocks at a time (small town) I get a wopping 12 in town.

Also dose any one have an idea how many HP/TQ a 42 RE can handle... buddy is trying to talk me into throwing a m90 on it to boost.

2001 Jeep GC Laredo
42RE
242
3.73 gears
2.5" ROR lift
30.5" Dyno Pro ATM

Thanks,
Jason

[Cheromaniac]

My highway mpg went up after I did the stroker swap and my city mpg was only slightly down, so overall mpg is still slightly higher than stock. Being able to maintain the same speed or accelerate with smaller throttle openings is what makes the difference.
The 42RE should easily handle the torque of a N/A stroker but adding boost will definitely require some tranny upgrades, not least a bigger tranny cooler.

[DaemonForce]

From the sound of that, I'm probably going to get frustrated with my A998, possibly try swapping in a 42RE and if that blows up, switching to a flywheel, premium clutch and an AX-15. I look forward to the part that works.

[Cheromaniac]

You'll definitely get better fuel economy with a stick shift and the Jeep will be more fun to drive.

[jason_alex_2009]

Sorry I am looking at adding around 4-6 psi of boost.

[DaemonForce]

I tend to read the 4-6psi/lbs? as a common expectation for these engines. I honestly expect them to handle more but then again we're not talking about the strip are we?

Forced induction is completely foreign to my building schedule but because I'm using hyper pistons, I think it's at least worth experiment. What should be expected of this cute little thing? :3

[jason_alex_2009]

I here is how I plan on mounting mine.... if i decide to go that "root"
http://www.youtube.com/watch?v=p2MOy3AKvps

[SilverXJ]

I tend to read the 4-6psi/lbs? as a common expectation for these engines.

If teh bottom is built to accept it with the correct compression ratio I see no reason you couldn't go 12 PSI or better. Teh thing is that the M90/MP90 will most likely make ~6psi with out over spinning the compressor. The more restrictive the head and exhaust are the higher the PSI though.

I here is how I plan on mounting mine.... if i decide to go that "root"

I would personally enlarge the outlet tube as well as the opening on the manifold if you go that route. The opening on the manifold is adequate for a 4.0L, but even with a larger throttle body on a stroker you need to remove some material. Now you are adding boost, which is hot compressed air. You need a larger opening.

BTW, check out a M90 build on NAXJA in the Street forum. A guy there is using a M90 and still keeping the AC. He has done a good job.

[jason_alex_2009]

Checked it out sweet build... my compressor is on the bottom being a wj so it looks like I could just pull a battery relocation and have the room for it.... as far as boost this is going to be some what of a DD so I dont want to go crazy, I am considering just running the stroker for a while then boosting later.

Thanks,
Jason

[Cheromaniac]

If teh bottom is built to accept it with the correct compression ratio I see no reason you couldn't go 12 PSI or better.

Except that at that boost level and beyond, I don't think that the stock or aftermarket MLS head gasket would hold up.

[jason_alex_2009]

just wondering on the stroker list it dose not show the hp ratting for the 944 with boost on a stock cam... any idea at 6psi what it would do?

[SilverXJ]

Except that at that boost level and beyond, I don't think that the stock or aftermarket MLS head gasket would hold up.

I know of two people that have had a head gasket failure under boost. One I believe was sixpack here and I don't recall what gasket he was using. The other was some clown on NAXJA.. but he was such that you couldn't believe a word out of his mouth. It has since been proven that the supercharger he was using would not make 12psi on 4.0L.

just wondering on the stroker list it dose not show the hp ratting for the 944 with boost on a stock cam... any idea at 6psi what it would do?

Not sure. Check back next year. I'm estimating 325-350 hp... if it doesn't detonate itself to death first. The stock cam maybe a bad choice here.

[wjtom]

I know ryan has done a bunch of boosted ones.No failures that i know of with head gaskets.Arp hardware would definitely help if youre going to push the limits.Pretty sure hes done a bunch over 10lbs with no failures.

[jeepxj3]

Not sure. Check back next year. I'm estimating 325-350 hp... if it doesn't detonate itself to death first. The stock cam maybe a bad choice here.

Nice, that must be crank hp. Any idea what the rear wheel hp might be?

[FlyinRyan]

I'll be doing a 15 psi turbo 4.0 shortly. GT3582r

We also did 18 psi through a stock 2.5....which is heavily based on the 4.0 .