2.5L stroker kits and cams etc

[JeepnGreg]

is there such a thing as a stroker kit for the 4 banger? i know cams are made...whats best and what type of gains can one expect......superchargers are too much $$$..im poor and its only a 4 banger...so i wouldnt wanna spend 5 grand.

i think Mopar has a performance racing crate 4 banger thats somewhere near 3.25L...i think it uses a head from the Hemi motor....so its like ahlf a v8....can i make the 2.5L that big [img]images/graemlins/grin.gif[/img]

lemme know, but keep the talk of "im better off swapping a v-8" for some other time. im just curious to see whats out there

[CJ7Taz]

The V-8 is probably a much more cost effective way of getting more horsepower. There just isn't that much aftermarket support for most 4 bangers.

Now, with that said, there is a lot you can do assuming this is a hypothetical question or you are racing in a 4-cylinder class and want to win.

Any engine can be stroked, it just gets expensive. A cheap method to gain a little stroke is to have the crankshaft reground off center. If you can find .050 under rod bearings, you can have the journals ground .025 off center and gain .050" of stroke and increase the compression ratio at the same time.

You could bore it out .060 is usually no problem. If we are not concerned about reliability, you can go a lot further than that but you may have to find oversized pistons from a different engine.

You can port and polish, balance and blueprint everything and run at a higher RPM which will give you more horsepower. With forged crank, proper rods, double valve springs, roller lifters, etc., you could get up to around a 10,000 rpm redline. If you've got lots of money, we could custom fab an overhead cam setup.

If we are not limited to the present engine and have no budget limitations, the possibilities really open up. With enough machine work, any V-8 could be transformed into a 4 banger. Pontiac did it with the 389 for the Tempest back in the early '60s by just deleting one bank. Other than capping off the missing portion of the block, the only other big problem is the intake manifold. Theoretically, you could go the other way and cut the four cylinders out of the middle, weld the front two back to the back two and build a V-4.

As you said, superchargers are expensive, but turbochargers are reasonable.

Forget the hemi, it's highly overrated. Just because it did great on the drag strip back in the '60s with a blower, don't mean it'll perform naturally aspirated. The hemi does alright but there are better places to start if you are not going to supercharge it. Of course, you do get the testosterone flowing bragging rights with the hemi.

Still, there's no substitute for cubic inches.

[Skellator]

Try asking that same question at 4Bangers United
[img]images/graemlins/RockOn.gif[/img]

[dorfs]

As Taz said, off-set grind the crank. But instead of off-set grinding it to fit the stock Jeep rods, go way down to the size of chevy rods and use Chevy rods and pistons. It will take a little research, but any good machine shop should be able to help you out. There is also the big advantage of using very cheap Chevy parts. This is the way Hesco builds their 4.7 stroker. May want to contact them for 2/3 of one of their kits. But Hesco expensive.

[desertbuzz]

I don't understand why would one wanna stroke a 2.5 4banger? [img]images/graemlins/lame.jpg[/img]
I'd assume it'd be easier, cheaper & neater to drop a 6 cyl 4.0..... no major mods to do.... definitely easier than dropping in a V8.... and the power and performance gain is tremendous compared to the ole 4banger.... [img]images/graemlins/burnout.gif[/img]
Down here a lot of jeepers ditched the 4 banger.

[GeeAea]

</font><blockquote><font class="small">In reply to:</font><hr />
I'd assume it'd be easier, cheaper &amp; neater to drop a 6 cyl 4.0..... no major mods to do.... definitely easier than dropping in a V8.

[/ QUOTE ]

Not necessarily ...the trans is different between the two ...so is the transfer case input splines (at least w/231) ...so now you're into a trans purchase and swap ..and at least some work on the t-case. Although the power difference would be substantial for any engine upgrade ..the costs would be equally substantial. For someone who can do the non- machine shop work themselves ..this would definitely give the cost edge (by far) to stroking the 2.5.

[desertbuzz]

I rest my case [img]images/graemlins/grin.gif[/img]
(I just hate that 4 banger [img]images/graemlins/lame.jpg[/img])

Since we're throwing ideas around...
With a throttle body you could always consider adding a turbo. The question would be the stock ECU. You could probably piggyback an electronic boost controller $300 or use a manual one way cheaper, use a chip $200?, a remanufactured turbo $600, a blowoff valve $150, and a buddy who can weld pipes and exhaust flanges. You can run a straight "hot pipe" until you can save up for an intercooler($800) or get one off one of those Volvo cargo trucks($100-200) It really isn't THAT difficult. You'd probably be safe with 5psi. My buddy and I are putting a Nissan Silvia turbo 2.0 into a '72 Datsun 510. I thought it would be kind of cool to put one on my 2.5L...something different.

[Olin18]

Since we are tossing around Ideas for a 4 dinger here is my .o2
Balance and print it so you can run at a high RPM. Go .o60 over. Add a turbo, it will work great if you are running a high RPM. Then round out the party with a NO2 kit.

[JeepnGreg]

this is a purely hypothetical thread by the way...im not super building the 4 banger....i dont have any money...i couldnt even if i wanted too! i will at some point get a whole new engine/tranny combo...but that way down the line

turbo woul be fun....it'd prolly break parts on the trail though, since it'd make sudden jump in the HP/torque.....

kinda be cool to tell people you have a Turbo Jeep :-p

what you alll think about turbos?? [img]images/graemlins/burnout.gif[/img]