mindless rambling/whining about power issues

[homey_15]

i've got a 86 cherokee with a 4.5 rubicon/home brewed lift, stock tow package (4.10's) and i'm rolling on 31x9.5 swamper tsl's. my problem is that i have a incredibly crappy powerplant (2.8) that doesn't like to cruize above 65, 70 i made a k&n cold air kit for it since nobody makes one and that made a noticable difference. i plan on either removing the cat or getting a high flow replacement because there's no doubt in my mind that the one i have now is plugged. i'll probabally go with first option because i'm poor. (i know i'm givin tree huggers somethin to whine about) i've also got a oem gm "hipo" cam that i bought from a guy with a surplus of them. supposedly he put one in his 2.8 jeep and there was a decent power increase. so that's waiting to be installed along with a set of original ported heads. i'm really wanting to go with some 31 10.50 bfg's. mud or all terrain, most likely mud. what i'm wondering is if i'll be able to pull the tires on top end. i can't decide what the problem is now, if theres so much rotational mass that it just cant do it on top (those suckers are heavy) or if i just have a chronic lack of power? most likely it's a combo of both but i want some other opinions on the subject. just for the record, i can spin the tires on anything thats not pavement but that could just be the 4.10's fooling me into thinking i'm not driving a turd. what's everyone out there think?

 

[rsalemi]

Problem only 173 cu inches

You have a Citation (remember those?) v-6 motor trying to move a truck and now you are adding weight and rotational mass and increased wind resistance. And you wonder why it won't cruise fast? A stock new 85 would barely do 85 MPH.
Forget the heads, the best improvement you can make on that combination is to advance the camshaft 6 degrees or so - you might do that with the new cam - and as for the cat - its probably OK because if it was blocked you wouldn't even be going 50 MPH.

 

[Eagle]

Actually, the BEST mod would be to find a 3.4L out of a Camaro, drop that in, and put the performance mods into that engine.

Agree with Bob about the cat. I had a plugged cat on my '88 4.0L MJ and it wouldn't drive the speed limit on a level highway.

 

[TRL WGN 1]

Sad thing is, you will probably be able to pull the 31" BFG's way easier than the TSL's, as they are heavy and pull hard. But, I also agree that putting money into a 2.8 is like flushing it down the toilet. A swap would be much better.
The cat could be restricking it some. Does the exhaust have a "hiss" sound to it? Since you gave it more air then it would help to open the exhaust some, to let that air out. Plus, it doesn't cost anything to remove the cat, so long as you don't have to pass inspections

 

[ashmanjeepxj]

Sad thing is, you will probably be able to pull the 31" BFG's way easier than the TSL's, as they are heavy and pull hard. But, I also agree that putting money into a 2.8 is like flushing it down the toilet. A swap would be much better.
The cat could be restricking it some. Does the exhaust have a "hiss" sound to it? Since you gave it more air then it would help to open the exhaust some, to let that air out. Plus, it doesn't cost anything to remove the cat, so long as you don't have to pass inspections

If you need the speed Id do the swap...

My yota has 5.29 gears in it and also came stock with 4.10s cause its a litte 4 banger 2.2L engine.

Its on a 5in lift and 33-1050 TSL and has good acceleration now. but has a max speed of like 65 in 5th gear.

If you dont need to hit 80MPH then Id sugest a regear.

 

[homey_15]

i plan on doing a 3.4 swap someday, finding the 3.4 is the problem cause i'm poor so i planned on doing some cheap/ free mods on the 2.8 and swapping the stuff worth keeping to the new motor (cold air kit, new hipo cam) since the engines are pretty much the same bolt for bolt. as far as a regear, i could do it myself and could probabally scrounge up a set for a decent price, hell i might even be able to find a locker but i wouldnt really be gaining anything here as i'm trying to pick up top end speed. oh, and about the cat, i've had them plug before and this one is definetly getting plugged, its just not to the point that its detremental yet. thanks guys.

 

[sidriptide]

B & M actually made small supercharger kits for the 2.8 back in the 80's... i see them ( the small blower unit) at swap meets all the time... they may still make them but i have no idea..... summers coming and the swap meets are gonna start springing up everywhere. cheap boost until u can do the 3.4...

 

[crimsonride]

Soemthing's not right with youre engine. I'm on 33's and 4:10's and I can make 75 on the freeway. It's a dog though, but you should be able to do a little better than what you're doing. I'm working on a 3.4 for it. You should have 110 hp claimed stock, the 3.4 fuel injected is 160 hp. You should be able to boost that fairly easily, the 60* engines bennefit from better oiling and roller cams. Also, if you eventually get one. Look into getting hypereutectic pistons. I the origional pistons glaze and lose compression. Suposed to be the result of some kind of coating on the origional pistons.
Oh yeah, I took off my cat and had a large, noticeable gain, using a K&N extreme flow filter and Gibson exhaust. I think they suffer from inadequate breathing.

 

[homey_15]

i took off my cat today and got a definet improvement, i was thinking about running dual 2" exhaust but am not sure if i'd see improvement. did you notice any extra power when you bolted on your gibson exhaust? also, i'm somewhat intrigued by the supercharger comment, especially since itd swap to the 3.4 when i get it. what do they usually run at the meets? thanks again.

 

[homey_15]

by the way crimsonride, what kind of tires are you running?

 

[5-90]

I'd go for the 3.4RWD swap (donors are Camaro/Firebird/S-10, and, I think, Astro/Safari and I believe going to a 4.3 is possible with some work - picture an XJ with 4.3 Vortec in place... Now I've got me thinking - 4.3V, 6# boost, regear, ...

Even the 3.1 is a better mill - the 2.8 is purely gutless. Make sure you don't get the FWD version, as the starter boss is on the wrong side and it will cause headaches for you. The V6-60 block is fairly plentiful...

Also, in case emissions is becoming a problem, you can make a 3.4/3.1 look like a 2.8 in place, and the sniffer measures relative levels and not actual volume...

5-90

 

[homey_15]

for now, unless i find a 3.4 for dirt cheap, i'm stuck with the 2.8. i definetly plan on swapping it out in the future though. i'm not exactly sure what i want to change to though. i've got a police interceptor 5.0 with the computer, wiring, all that neat stuff that makes it run just lying around so i was thinking about dropping that in backed by a c4 and a dana 20 out of a EB. i thought it through and i'd have to have driveshafts made, have exhaust ran, and some other little stuff and i think i can do the 5.0 as cheap if not cheaper than the 3.4 because for some reason, everyone thinks 3.4s are worth their weight in gold. as for swapping in a 4.3, its a 90 degree motor, just like a SBC so if i was going to all the work to drop in a 4.3, i could do a smallblock just as easy. anyone see any reason the 5.0 swap wouldnt work and do you know of anyone who has done it already? thanks again.

 

[woody]

Another interesting swap besides the 3.4l V6 Camaro/Fbird mill is the Caddy Shortstar 3.5l. 260hp/260lbf in a 330# wrapper= see the May 03 JP mag Pp52 for more insight.

It isn't a true bolt-up like the 3.4 RWD would be (bellhousing mods), but those #s make it awful appealing as a project. If the strip is stil open across the hwy from the airport out there, you'd be a Friday Night Hero with that + your 4.10s. Plus 260 LB/FT be good on the trails too.

Best bet is to peer upon www.car-part.com to help find what you need, but don't discount the local (non-wired) yards and bodyshops for a rearended camaro/f-bird or caddy.

I personally wouldn't spend a dime on a 2.8 (or even own a 2.8 Jeep unless a swap was planned for) but ya gotta dance with what brung ya.

HTH

 

[homey_15]

i assume you mean northstar? arent these motors transverse mounted? what exactly will i have to do to the bellhousing to make it bolt up? any "neat" stuff thatll make this swap a pain in the ass that i oughta know about before investing a bunch of time and/or money into checkin into this? thanks again, you guys are alot of help.

 

[crimsonride]

Nope, he meant the short star, they're a V6. Smaller version of the V8. I've been looking at them but they're expensive and not very common. Pretty new too.
My tires are BFG mudds. I love them. I had thornbirds. Worst tires in the world. They suck for wheeling.
I noticed a BIG increase (if you can say that about my engine) when I went to my new exhaust. It was a Gibson Grand Cherokee exhaust, I had new pipe bent for it and the shop just removed my cat since it was so banged up and shot. It's 2" pipe. I would stay away from dual. It just doesn't look right on a cherokee. Kinda poserish.
If I were you I'd go with that 5.0 idea. It's been done before and worked out nicely.