Calgary Jeep Association
4x4 Related Groups => Tech Talk => Topic started by: SWJeep on September 17, 2006, 08:53:50 AM
-
Has anyone put a turbo on a 2,5L? Is there a lot involved? Someone was telling me that you could get them off of some old Doge mini vans, that would fit.
-
As far as I know, Avenger makes one for the 2.4L, and the 4.0L. Other than that I haven't seen any other super/turbo kits for the TJ.
-
I think Avenger is working on a soon-to-be-released supercharger for the 2.5L. I could be thinking of the 2.4L, i don't remember.
-
I am putting one together soon for my 2.5l (could be early next year though). My friend is a cnc machinist and has made me several turbo manifolds in the past. We are trying to put together someting that will develop around a 100 hp increase thats very reliable. There is alot involved (ie. tubo sizing, fuel managment, high volume fuel pump, FMU and or pressure switch with coldstart injector,boost friendly map sensor, oil supply and or coolant supply, boost pipes, intercooler [if you want more than 4-5 psi], blow off valve. If you are still interested, or for more info PM me.
Mike
-
Just a thought for you guys, have you looked at the bottom end on the 2.5?!?!? The big end of the rod, is not that big, not to mention, Isn't the 2.5 roots, based in the old AMC? made to produce something like 90 HP? we've already upped it too 115-125-ish..........i'm not sure about the engine's ability to accept the boost necessary to basically double it's horsepower output.
A 20 HP increase....I could see that being reliable.....but that's just my 2 cents.....
-
Just a thought for you guys, have you looked at the bottom end on the 2.5?!?!? The big end of the rod, is not that big, not to mention, Isn't the 2.5 roots, based in the old AMC? made to produce something like 90 HP? we've already upped it too 115-125-ish..........i'm not sure about the engine's ability to accept the boost necessary to basically double it's horsepower output.
A 20 HP increase....I could see that being reliable.....but that's just my 2 cents.....
You are right that a 2.5 is an old 4.2 with 2 cylinders cut off. As simple as that.
But,
That same crank and rod desing and size is whats used to build today's 4.5, 4.6, and 4.7 litre strokers that push as much as 500hp and 650lbs of torque. 500hp being the blown, and stroked motor they put out.
There is a guy who built a natural 2.5 to put out 220 plus hp. His right up is on the 4 banger jeep forum.
Avenger has been putting blowers on the 2.5's for a few years now. No word of it being an issue.
Built right, there should be reason a tuned up little 2.5 wouldnt last.
-
some of the 80's dodge cars came with turbos maybe you could adapt somthing. My 87 Dodge colt had a turbo (but a mitsu. engine) and some late 80's and early 90's shadows and lasers came with turbos.
-
Thanks for the insight....
My automotive experience is limited....
I had a 2.5 throw a rod, and when I took the engine apart, I couldn't believe how small the big end was. not to mention the total weight/heft of the piston/rod assembly.
My experience comes from Superbikes and such, and when I was lookin' at the 2.5, it just looked soooo archaic.....
-
The rods seem to be much thicker than my hondas (60 thou bigger). And a good rule of thumb is at double atmos. press. (1bar) which is 14.7 psi you double your hp output (engine, not wheel). good tuning to keep your a/f ratio at stoic. or even a little rich (self assurance), can get you a little more or less depending on the situation.
Now my honda (1.6l DOHC VTEC) put out naturaly asperated 167 hp (engine) boosted to 10 psi with very good tuning (wide band O2, computer crap, running perfectly stoic.) put down 313 wheel hp. Now 10 psi boost on 10.5:1 compression ratio is the very limits of that engine.
The rods on the 2.5l are thicker and the compression ratio is much smaller at 9.5:1, should accept boost nicely (theoreticly). I want to run between 7-10 psi safelyand intercooled (ruffly 185- 205hp).
-
Interesting stuff.
What will you do to make the power at the bottem? Is there a way of tunning the turbo impeller or something else to eliminate, or minimize lag?
How will you address mud? Jeeps are a SOB to keep cool, and thats 10 fold when you start packing mud into the rad. An intercooler in front will compound that issue.
What kind of money do you think you will be looking at? You think this will be a one off, or something you might start doing for a people locally for a few $ on the side?
My wifes is a 2.5 and could use a bit more pep, although it does fairly well offroad.
Might be interested in this if you come up with a clean system that works well.
-
I thought the 2.5L was a whole new engine, because the 4.0L was based on the 2.5L, hence the interchangeability of parts.
-
Other way around.
The 2.5 is literally a 4.0 with 2 cylinders chopped off.
The 4.0 is only a slight variation from the old 4.2. Again, why mostly everything is interchangeble there as well.
-
Actually Bnine, in JP a few months ago it stated the 4.0L was based off the 2.5L
-
Have to be carefull how you take what you read.
I thought it was the 4.2, but wasnt sure where the 2.5 came from.
Anyways, the 2.5 is a 6 with two cylinders cut off.
When they re vamped the 4.2 to the 4.0, they mimic'd some dimesnions from the 2.5, but.....
You can still take everything off of a 4.2, exhaust, intake, crank, rods, cylinder head, etc etc etc, and bolt it on to a 4.0
The 4.0 still excepts the same camshaft used in that basic 6 cylinder design since 1956. You can go to cranes site and look up 4.0 cams. The specifics are "AMC 6 cylinder, 1956 and up"..........lol
THe only thing they did was change the bore and stroke on the 4.0, the same as they did when they designed the 2.5
So its kind of a chicken before the egg thing, but basically, the root design of the 4.0 is 30 years older then the original 2.5
Saying the 4.0 was designed based on the 2.5 is a bit misleading IMO.
-
I dont know much about the 2.5L - if I ever replace my willys Fhead I would look here first to keep it jeep;
I had a 4L in my long gone cherokee :( , missed it so bad my old yj engine top is now a 4L HO -- I put as many 4L parts I could find on my 4.2L :D , I run a prep'ed 91 4L HO head (water jackets closed ) with same year headers, MPI intake and distrib off a '95 , 4L head gsk, 4L thermostat & housing etc, reused old 4.2L pushrods and all stock there down .... thats where the canibul comes from ..scavenging some of the better parts to keep the old yj going ...
there's something about turbo's vs. superchargers that comes to mind, if I got it right superchargers make torque (offroad=good) and turbo's make horsepower (onroad=good) ... ?
I think avenger is only building superchargers for jeeps
http://www.rockcrawler.com/features/newsshorts/01july/avenger.asp
I did a trail two years ago with a tj from G. Prairie that had one installed similar to pic .. only 1 I have ever seen , .... it was spinning '37's pretty gooooooooooood ....
-
Bnine to answer the question obout turbo lag. my friend the cnc machinist and i are going to port & match the intake and exhaust ports as well as polish the exhaust for way more reliability and cut down on the chances of detonation. This should also add more power. as for money we have done the math and a good turbo 200-500 dolars intercooler 300 (core from mack truck and new tanks welded on, cut down to size that fits). Machining free, manifold (he wants to teach me how to use the cnc, so just the blank metal. welding(now thats an art) I dont weld well so ill have to pay to get that done. really the only thing we would have trouble with would be fuel management, its THE HARDEST PART. The intercooler I would either top mount with brakets paralel to the hood and add a hood scoop (functional no laughing please) and for those times when you are crawling I would add a small pull elec fan, ie. from a firefly. And with the intercooler on the top the boost pipes would be very easy to route, keeping everything nice and close. Also on the LAG portion you can get hybrid turbos ie t3/t4 or I believe t3/t66 is another one these are very tiny exhaust prop with larger comp end. this = extreame quick spools and tons of volume. only prob with more vol. larger chance of boost creep. Your right though supercharger probably better for low speed crawling. but Those kits are like 5g notes arent they. I plan on spending way less than one thou. yes this will probably be a on off, for now untill all bugs are addressed. Then I will talk to my friend Leen and well keep the kits cheap. But lets face it anything is better than the stock 123 hp.
-
Cool, look forward to seeing what you come up with.
-
Oh and yjcanible, all boost equals more torque. Stock 2.5l= 139 lbs/ft with a turbo at approx. 7psi boost you get roughly a 50% increase in peak torque. Roughly 70 lbs/ft more so 210 total (again very rough estimates could be more could be less). the only diffeerence is the exhaust needs to be pushed through the turbo to get it going, hence lag. at WOT with a good matched turbo could be fractions of a second. this results in higher torque out put but also at a higher engine speed ie 210 lbs/ft at 4200 rpm vs 139 at 3200 rpm.
Boost is definetly different and takes some getting used too.
-
thanks Buki , I like and cant argue with those numbers, my thoughts were the aftermarket is mostly making superchargers for offroad cause you can use them at lower engine speeds to make the same/similar torque which if correct seems to be desirable, I know they both offer lots of power improvements but where and how they make it in the powerband seems tobe whats important ...
this is a question more then a statement - I thought you had to push the vehical ( gas pedal = down, rpm = up ) to make use of the turbo and because they spin at 20,000 rpm they are really sensitive to dirty air opposed to a s-charger ...
thats a pretty huge undertaking and let me know how it goes cause I am always interested in such things and learn lots from these discussions ...
:)