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rev limiter question ( mines funer than yours)
Posted: Sun Sep 12, 2010 7:22 pm
by wesley4x4
soooo i have a secret... my jeep has a straight pipe with no muffler ( but i got me a kitty cat under their still)...
I KNOW IM A HORRIBLE MAN
but get this... it sounds a lot better than a borla and produce's more low end hp (by feeling idk if its just in my head
) but anyways
this exhaust is fun to ping off the rev limiter like really really fun and someone came up to me telling me im going to blow my engine (the guy sounded like a mr.knowitall douche) and i said your wrong and he said fine have fun blowing your 1.0 i LOLED
really hard because i took 2 4.0 stickers and chopped it so it said 1.0... you'll have to see it
any ways.. i know factory sets the rev limiter way below blowing point on these engines and just wanted your input
5500 is my rev limiter and ive been hitting it off and on whenever im in a bad mood or just get that sugar spaz rush to bounce it off the rev limiter
is this bad or rrreaallly good for the engine
to only do it once in a while
im going to say it doesn't hurt it but i just want your fancy smancy inputs
its all like bwwwaaaaa bap bap bap bap and if i put pressure on the stick it power shifts itself... pretty neat and sooooo healthy for the ax5
NOOTTT
Re: rev limiter question ( mines funer than yours)
Posted: Sun Sep 12, 2010 7:53 pm
by johnsxj
It's not the best thing for the engine, but it probably won't blow with a rev limiter built into the computer.
Re: rev limiter question ( mines funer than yours)
Posted: Sun Sep 12, 2010 8:26 pm
by ZAEDOCK
The guy is probably right. If you continue to rev an engine to red line without a load on it, you'll eventually damage your rings or spin a rod bearing.
Just because it has a rev limiter, doesn't mean it's good for it. Expect me to bust on you when you post your WTB a 2.5L engine thread.
Re: rev limiter question ( mines funer than yours)
Posted: Sun Sep 12, 2010 8:42 pm
by johnsxj
Re: rev limiter question ( mines funer than yours)
Posted: Sun Sep 12, 2010 8:55 pm
by Hoodoo Man
Re: rev limiter question ( mines funer than yours)
Posted: Sun Sep 12, 2010 9:20 pm
by ChrisD
We love ya Wes, but please don't have kids...
Re: rev limiter question ( mines funer than yours)
Posted: Mon Sep 13, 2010 12:10 am
by wesley4x4
well every time i hit the rev limiter its always for a second and their is always a load on the engine when it happens... sometimes it usually happens (not on purpose) when im merging onto the highway... just was always told that the rev limiter is set lower than the factory settings and told i wont damage anything unless im just sitting their for about 20-30 seconds just slamming it off the limiter... but anywhoo thanks for the info and
LOOKS LIKE A STAGE 2 CAM UPGRADE IS GOING IN PLACE!!
Chris wrote:We love ya Wes, but please don't have kids...
joes kids turned out normal sooo ....... you LOL J/K
Re: rev limiter question ( mines funer than yours)
Posted: Mon Sep 13, 2010 9:52 am
by nostaw
wesley4x4 wrote:well every time i hit the rev limiter its always for a second and their is always a load on the engine when it happens... sometimes it usually happens (not on purpose) when im merging onto the highway... just was always told that the rev limiter is set lower than the factory settings and told i wont damage anything unless im just sitting their for about 20-30 seconds just slamming it off the limiter... but anywhoo thanks for the info and
LOOKS LIKE A STAGE 2 CAM UPGRADE IS GOING IN PLACE!!
JP did an article fairly recently comparing (re-)gearing the axles (4.10 -> 4.88) vs. trying to get more power out of the 2.5L.... The conclusion was that re-gearing offers more usable results than engine mods do. You may want to look the article up and see what they did before you sink a lot of $ to mod the engine. I think all of this was with ~31" tires...
JW
Re: rev limiter question ( mines funer than yours)
Posted: Mon Sep 13, 2010 8:42 pm
by ZAEDOCK
My butt dino tells me I make more HP than I used to, but that's after head/intake work, a 4.0L TB (with enlarged intake), and electric fan (which died, so I'm back to mechanical). I guess I'm making about 135-140 HP. The 2.5L is a purpose built truck engine (w/ a long stroke) designed to chug along and get decent mileage. AMC did a great job, but it's still only 150 cubic inches. Gears are the best help for a 2.5L and make it work a little easier.
I like my four popper because I would probably break 10X's more doo-dee with a V8. See, it saves gas AND money in borken parts.
Re: rev limiter question ( mines funer than yours)
Posted: Mon Sep 13, 2010 10:21 pm
by wesley4x4
ZAEDOCK wrote:My butt dino tells me I make more HP than I used to, but that's after head/intake work, a 4.0L TB (with enlarged intake), and electric fan (which died, so I'm back to mechanical). I guess I'm making about 135-140 HP. The 2.5L is a purpose built truck engine (w/ a long stroke) designed to chug along and get decent mileage. AMC did a great job, but it's still only 150 cubic inches. Gears are the best help for a 2.5L and make it work a little easier.
I like my four popper because I would probably break 10X's more doo-dee with a V8. See, it saves gas AND money in borken parts.
exactly
and if i throw a rod or slip a bearing ill just get a rebuild kit
the reason for the stage 2 cam kit would be you could redline at 8000k and still not be damaging anything
Re: rev limiter question ( mines funer than yours)
Posted: Tue Sep 14, 2010 10:26 pm
by ZAEDOCK
wesley4x4 wrote:exactly
and if i throw a rod or slip a bearing ill just get a rebuild kit
the reason for the stage 2 cam kit would be you could redline at 8000k and still not be damaging anything
There is no way in hell a Jeep 2.5L pushrod engine will ever rev (or for that matter, live) to 8,000 RPM with only a cam kit. It doesn't work that way.
Re: rev limiter question ( mines funer than yours)
Posted: Tue Sep 14, 2010 10:57 pm
by wesley4x4
ZAEDOCK wrote:wesley4x4 wrote:exactly
and if i throw a rod or slip a bearing ill just get a rebuild kit
the reason for the stage 2 cam kit would be you could redline at 8000k and still not be damaging anything
There is no way in hell a Jeep 2.5L pushrod engine will ever rev (or for that matter, live) to 8,000 RPM with only a cam kit. It doesn't work that way.
well the cam kit (rebuild kit)
*comes with a new cam shaft
*rods
*valves
*head/rocker arm system
*forged steel cylinder and arm kit
i think sooo
http://en.wikipedia.org/wiki/Overhead_valve
read limitations
or leme paste it
Some specific problems that remain with overhead valve (OHV) engines:
* Limited engine speeds or RPM ? OHV engines have more valvetrain moving parts, thus more valvetrain inertia and mass, as a result they suffer more easily from valve "float", and may exhibit a tendency for the pushrods, if improperly designed, to flex or snap at high engine speeds. Therefore, OHV engine designs cannot revolve ("rev") at engine speeds as high as OHC [3]
Modern OHV engines are usually limited to about 6,000 to 8,000 revolutions per minute (rpm) in production cars, and 9,000 rpm to 10,500 rpm in racing applications. In contrast, many modern DOHC engines may have rev limits from 6,000 rpm to 9,000 rpm in road car engines, and in excess of 20,000 rpm (though now limited to 18,000 rpm) in current Formula One race engines using pneumatic valve springs. High-revving pushrod engines are normally solid (mechanical) lifter designs, flat and roller. In 1969, Chevrolet offered a Corvette and a Camaro model with a solid lifter cam pushrod V8 (the ZL-1) that could rev to 8,000 rpm. The Volvo B18 and B20 engines can rev to more than 7,000 rpm with their solid lifter camshaft. However, the LS7 of the C6 Corvette Z06 is the first production hydraulic roller cam pushrod engine to have a redline of 7,100 rpm.
* Limited cylinder head design flexibility ? overhead camshaft (OHC) engines benefit substantially from the ability to use multiple valves per cylinder, as well as much greater freedom of component placement, and intake and exhaust port geometry. Most modern OHV engines have two valves per cylinder, while many OHC engines can have three, four or even five valves per cylinder to achieve greater power. Though multi-valve OHV engines exist, their use is somewhat limited due to their complexity and is mostly restricted to low and medium speed diesel engines. In OHV engines, the size and shape of the intake ports as well as the position of the valves are limited by the pushrods.
Re: rev limiter question ( mines funer than yours)
Posted: Tue Sep 14, 2010 11:06 pm
by johnsxj
How much does it cost, and is it REALLY worth it?
Re: rev limiter question ( mines funer than yours)
Posted: Tue Sep 14, 2010 11:14 pm
by wesley4x4
johnsxj wrote:How much does it cost, and is it REALLY worth it?
is so unpractical i love it lol im just kidding and just messing around with you guys about the idea
but its on the market so someone must have bought it and did the conversion... they also make the kit for the 4.0
Re: rev limiter question ( mines funer than yours)
Posted: Wed Sep 15, 2010 10:13 am
by ZAEDOCK
I know all about valve float. Started in drag racing prior to Jeeping. I used to shift my small block powered Malibu at 6,000 rpm. The valvetrain uses solid lifters and high pressure valve springs.
I've looked into the mopar stage 2 cam for the 2.5L. It moves the torque curve up in RPM and would make trail performance suffer. If you don't have the gears to be happy now, adding this kit would actually make it worse.
If you were to get the kit, the rebuild on the 2.5L will cost you about $1500.00 assembled. Having the machine work done and assembling it yourself would save a ton of money. Still, I think a supercharger (even at $3K) would give much better performance tossed on a stock engine than having a custom grind cam in an N/A motor.
I have three small block Chevy's in my shed and the right bellhousing to mate it to my SM420. I'm just not ready to take the plunge in my YJ. My little 2.5L sucks on the highway, but I always make it back to camp after a run. Even though it sucks, it has a character than can not be described. Having to floor it so I can make the hills in western MA or NH still puts a smile on my face. The trail performance is pretty good (except maybe deep mud), and I think I use much less gas than a 4.0L (less load due to gearing helps).
I'm going to get my fun with a V8 though, as I've finally decided on a drivetrain for my buggy. It will include a 350 Chevy ('carbed), SM465 tranny, and either a NP203 or NP208 Tcase. The rear axle will be a 14 bolt and the front a Dana 60. These are all going into a TJ carcass.