91 BangNbuck

I'm almost ready to start piece n together the components for my stroker motor, but I can't seem to decide which way to go. I've always had Nitrous on every race car I've built and pretty much every car I've ever driven, but almost never been High Compression NA. So question I know it's preference but I'm building this for mud not a 1/4 so it's different. Any one already done this either N2O or NA with either good or bad results? I'm just looking for some opinions. I'm going either 10 1/2 - 1 NA or Nitrous. And I do realize I could go NA with the nitrous hooked up just in case with the high compression.

Evil Bender

Having had cars with Nitrous I dont think I would go that way with a 4.0 .I think higher compresion would be the way to go ,but 10.5 seems high.If your tunes not spot on AND you get some bad gas it could leanout and burn it up.What about Water Methonal?

91 BangNbuck

I don't think I want to go that route lol it's gonna be NOS high comp or NA. I'm leaning more towards the NA side anyway I guess I'm just trying to get someone to convience me other wise

J Pugh

I finished my stroker about 8 months ago. It is high compression 10.6:1 with a Comp 68-239-4 cam for a DCR of 8.9:1 and it's zero decked with a quench height of about .043. Two points I'll make here:

1) Don't go any higher than about 8.7:1 DCR. I am doing a LOT to control heat, and I still get some light pinging in the summer. And I have a good quench height and a notched block. I was going for an extremely efficient engine, and I guess I got it, but in retrospect, I'd rather not have it make so much damned heat, because as everyone knows, these motors blow at staying cool as it is.

2) The AMC straight 6, while a tank, is not very well engineered for high performance. I think Nitrous would be a waste of time/money/energy. Not to mention, I doubt that you'll ever be in a situation where you would need the extra power, I make almost 280rwtq at 3k. I just don't see the point for Nitrous at all for off roading, unless you are actually racing, like high speed.

Hope this was helpful. I think this might be the first time I've posted on CF...

91 BangNbuck

No it was helpfull I am utilizing my jeep as a daily driver/advanced 4 wheeler/ mud bog racer so I'm trying to design/build it to dip into all three categories. I'm basically going to pick a cam I like and build the motor around it. As far as your heading problem did you ever think about trying like a top mount intercooler or radiator? I don't know if it would work, but I'm sure a little custom fab and it would work. My problem is finding a cam I don't know what I'm looking for!!!!

Kamaran

High comp and meth injection. If you read up on meth injection you'll see how amazing simple and how much benefits there are.
I come from the turbo world. I just got done building a lexus IS300..its got a 2jz. I built it and the guys running 701whp daily in it.
Meth injection will cool off the intake charge, help prevent detenation and also steam clean your motor, so no more carbon build up ever!!
With the small amount of reasearch I've done, I would do 19lbs injectors & meth injection. The meth will substitute for some fuel so bigger injections shouldn't be needed..if anything a small upgrade and thats it.


But you said your a mud racer right? Well doesn't that mean you need power quick and now, like right off the jump?
nitrous will give you that, if you can control the wheel spin enough. For what your doing I honestly see nitrous being far more beneficial and cheaper...to start with lol. Refills get expensive.
But I would have to vote for a high comp stroker as well. Just remember they will both bring power on differently!
The high comp stroker will bring power on later and depending on your cam..that'll pretty much decided your power band.
The nitrous will be instant and come on alot stronger.


My advice is do a decently high comp, long rod stroker! With meth injection I can tell you now, meth will take care of the heat problem people see when doing these kinds of motors.

Kamaran

Ok I've reread this to get a better understanding! I saw "daily driver & mud boger & wheeler"
So I have a few questions..do you have E85 local to you? If so then you just found out what fuel you'll run. Its cheaper, helps the enviroment and you'll make more power on it.
With E85 though, you'll need a bigger fuel pump & bigger injectors...I'm talking bigger than most people run and more fuel pressure couldn't hurt. Reason for this is because you'll burn almost 2x as much E85 as normal gas!

If thats not an option for you then heres my advice...
Do a long rod stroker...long rod because the longer rods give better rod angels, inturn you'll get better longevity out of the motor. Also you'll have to have forged pistons which is a major plus!
And alot of people tend to say the longer rods will make more power per RPM vs a shorter rod...google search and find the reasons! Its far too much to type out lol.
Don't go to high on the compression, do just enough to where your safe on 91/93 oct, do a header & nice 3" s-pipe/downpipe and a nice 2.5" exhaust.
I would run a Comp 231 cam if its still a daily driver. It'll make the power you want and still provide tons of torque down low.
When building your motor, make sure you go .60 over which would be a 4.7L stroker. I say .60 over because it'll unshroud the valves and you'll get a more complete burn and more power because of this!!

My goals or moot points on a stroker build would be keep the heat in the exhaust and out of the intake! So ceramic coat the header & downpipe. Also ceramic coat the intake manifold and use that heat sheild/wrap stuff.

So far on my stock Renix 4.0..not the high output. I've wrapped my header, got a 60mm throttle body & spacer. Used the head sheild stuff that Dino savva used, and relocated my IAT sensor & did 703 injectors. I've also done a high flow cat and a Magnaflow muffler, its 2.5" from the flange by the crossmember back.
I also added my stock air box back in, and use the 97+ lower portion. I did this because on the Renix lower intake box, I have a valve and such on mine for the egr. With the 97+ lower I can do a cowl snorkel and only have to block off 1 hole v/s 2 with my Renix. Its just easier.

With these few upgrades I've done, I can outrun my buddies 96 4 door 2wd jeep xj. Hes got a K&N intake, 99+ intake manifold and a throttle body spacer, and no exhaust..He runs a stock header, stock downpipe, stock cat and a turn down directly after. Hes 30x9.5 AT's with stock 3.07 gearing and a NV3550. He was converted from 4wd to 2wd.
I've got the mods listed above and 3.07s with my 31x10.5 tires, also a ax-15. I've got more/higher mileage on my motor as well!
I know these slight upgrades have helped my jeep so much. I can now bark the tires in 3rd gr if I try lol. It would never do that before.

Gee oh Dee

With n2o you have to fill the bottle every once inawhile.

Just stroked all you need is fuel.

Kamaran

Exactly the n2o will add up in cost quickly..even if its cheaper to start. I say do a good strong 4.7L build, don't go high comp and have fun. I highly doubt you'll need more than what a stronger 4.7L can provide.

91 BangNbuck

I got E85 down here for sure I also got 110 AV gas!!!!! I'll have to do some research in the meth injection I don't know alot about it. I know ALOT about nitrous I've had it on just about everything including a go-ped and my Grizzley 700 FI quad lol. But I'm taking alot of my advice from my buddy and my brother. My buddy build retarded 1000+ HP Vets and my brother is a gear head @ Toyota. I trust them with the motor questions because I don't know as much as they do or YOU ALL for that matter. I'm good with tear down, put back together, superchargers, turbos, and nitrous that's about it. Tech talk not so much lol. But I shall check into meth injection. See the jeep is my hunting jeep sometimes I'm cruising through some nasty crap in the woods that's why I say it's my daily driver and I wanna start racing in my local mud bogs there's alot of cash and the last couple of times the people winning em I could prob **** faster than it takes them to go from A-B lol. But is it better all torque and tires or torque tires and the HP? Lol I don't know these things I got 30' BFG AT's on now but as soon as I can find some Cheap 2" spacers I'm putting on the 33" Super Swampers I it laying around.

91 BangNbuck

Kamaran

Your an have a auto trans right?
I'll throw out what I know for ya lol..you don't want wide tires in mud racing because you'll push through the mud, instead of just cutting through it..If you can get some 33x10.5 those would be great! Or similar of course..you mention swampers. I believe they have a 33x9.5 which would be awsome. But I'd stick with a 33x10.5
Not only in mud racing but daily driving as well, the 10.5 will get better mpg than a 12.5!
If you have an auto that means you have 3.55 gears. So with 33's your gonna lose some of that umph but thats not to big of an issue...read ahead lol
Most guys will start out in 2nd gear so they don't get the wheel spin..you just want to get up and go, not waste time spinning your tires! So with 33's and 3.55's you may be able to make your first gear useable..as in not spinning your tires.
I say grab a buddy and go try some runs. Have your buddy time you! Always run in 4HI and try starting in first and second. See whats faster, and see how much wheel spin you'll get.
I would start in second and load her up on the line. As in holding gas and break down, and as soon as your green to go, let up on the break. You shouldn't spin too much because you'll be starting in second, and you should still have good get up and go since your loading up the motor. I think in first gear your just gonna blow the tires off!
I say ditch the meth injection idea!! Its just 1 more thing to worry about incase something goes wrong! I would run E85 the whole way. Its great if its available to you. You'll make more power and burn cleaner!


If your truely serious about this, then I would plot out your moves and go from there! Starting with a lift and tires!
Keep your rig low and stuff in some 33's. I would try for 3-4" lift and 33x10.5. Keep your 3.55's!
Start gauging your motor..figure out what you'll need and or want with it!

Heres my plan for my motor just to give you some ideas.
When I build my motor, I'm doing a HO head swap since I have a Renix.
So I'll be cleaning up and mildly porting & gasket matching my HO head. I'll be doing SBC (smallblockchevy) swirl polished and undercut valves. They are very slightly bigger than stock..not even enough to matter, but what will help is the swirl polish and undercut stems. Thats the main reason for doing them, and they are cheap! I'll be running a stock cam also!
For the short block, I'll be doing a OEM rebuild! Yup no stroker here! It'll be .60 over to unshroud the valves, and stock polished rods. All of it will be balanced and blue printed.
My main goals for the motor rebuild are to gain effciencey and power. Not focusing on anything but effciencey, gaining power is a bonus is the way I see it!

I'm also kicking around the idea of using a 4.2L short block..So I'd just swap in a 4.2L short block, while using the 4.0L and everything else! My reason behind this is because the 4.2L should help bring on power a little sooner. And its a 4.2L so a minor displacement gain!
If I do this I'll still do a .60 over and use the same 4.0 stock cam. I believe because the shorter stroke it'll bring power on sooner and since we only run to 5k at most why not take advantage of more power sooner lol.
I think with the 4.0 cam in a 4.2L block, with a 4.0 head it'll run just like a 4.0 but bring the power on sooner..at least thats what I'm hoping. And since we only run up to 5k, it should be able to hold power through out the RPM range!
Also with the 4.2L block, I can use the 4wt 4.2L crank which weighs like 9-10lbs less than the 4.0L crank. It will give me a lighter rotating assembly and mass which means it be better on gas and want to rev up quicker. I'm going over every possible with this idea. So far I haven't seen much negative at all! And so far it looks like I'll be grabbing a 4.2L block and going after it!

Again I'm currently doing my homework on this project! So if you know something, then correct me and let me know!

91 BangNbuck

I definitely agree on the tires with you the super swampers are 33x10.5. And I have an RC 4.5" lift alread on there with the tires I'm clearing about 6" I don't want to go any bigger on the lift well I would, but it's not practical. Now I don't know **** about the E85 I can run that on just the stock motor with out having to convert anything? I thought you had to make some minor conversions with most Fi cars to run E85 unless you buy the new Bio Flex fuel cars. I'm still researching for a cam I really have not figures out what I want......i know I want a roudy/aggressive cam but....I don't want a cam that like you said I'm gonna be spinning and putting on a show instead of driving hahaha.

Kamaran

You want the comp 231. It holds power up top but still makes great low end! I think its the best all around cam, and if you've got headers & a 2.5" exhaust, you'll still hear some of that cam lope!

As far as E85, you have to remember you need almost 2x the amount of E85 to equal gas. So you'll need bigger injectors at minimum and maybe a bigger fuel pump. Idk the limits of our fuel pump..but to be on the safe side I'd ust upgrade it.
I'd look into 24lbs injectors and a Walbro 255lph. Both can be had for about 250 all together.
E85 is cheaper than gas, so even though your burning 2x as much it may still very well be cheaper. Do some searching on google and you'll get your answers.

Get you some 33x10.5's and go launch her and get a few runs it. Find out the best method to use. I bet loading her up and going will be the fastest!

91 BangNbuck

Yea I gotta do so more research. But good looking out thanks.