• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Anyone running turbo 2.5L ?

R

RJJR

NAXJA Forum User
Location
Montgomery, Texas
I have a 96' with the 2.5L and a freshly rebuilt ax5. I am comtemplating fabbing up an affordable turbo setup, Ive searched and havent found much info on a forced induction 4cyl. So does anyone have any oppinions as to which turbo to run, with good streetablity, and tq. I was thinkin a turbo out of the late model subaru wrx, since those can be had for pretty cheap.
I really do not want to do an engine swap due to how much $ ive invested into the current driveline.
So does anyone have any oppinions, or creative ideas?
 
I've contemplated it myself and have done a little research. Finding a turbo that mechanically adapts is easy. What I am having problems with is getting the computer to adapt. But mine is an early model 2.5l. I would bet that your computer could be reprogrammed to accept inputs from the boost. As far as torque, the turbo won't get you a heck of a lot more torgue, mostly plain hp. Would greatly increase the streetability though. Avenger makes a supercharger but it costs $3695.00. Where can you get a turbo from a WRX?
 
A WRX turbo is too small for a 2.5L Its actually too small for a WRX. I build custom turbo kits as a hobby. You should be looking more in the T3 .60/.63 area. Or at least a .48/60 60 trim.
 
HossHoffer said:
I've contemplated it myself and have done a little research. Finding a turbo that mechanically adapts is easy. What I am having problems with is getting the computer to adapt. But mine is an early model 2.5l. I would bet that your computer could be reprogrammed to accept inputs from the boost. As far as torque, the turbo won't get you a heck of a lot more torgue, mostly plain hp. Would greatly increase the streetability though. Avenger makes a supercharger but it costs $3695.00. Where can you get a turbo from a WRX?
Click to expand...

Torque is a measurable value, hp is calculated based on rpm and torque. If the hp increased, at any given rpm, then a torque increase is what made it happen.
 
RJJR said:
I have a 96' with the 2.5L and a freshly rebuilt ax5. I am comtemplating fabbing up an affordable turbo setup, Ive searched and havent found much info on a forced induction 4cyl. So does anyone have any oppinions as to which turbo to run, with good streetablity, and tq. I was thinkin a turbo out of the late model subaru wrx, since those can be had for pretty cheap.
I really do not want to do an engine swap due to how much $ ive invested into the current driveline.
So does anyone have any oppinions, or creative ideas?
Click to expand...

Go to the junk yard and get a turbo out of a 2.2 Chrysler Lebaron/Spirit there are tons out there and they're cheap. My buddy used the same turbo on a stock worn out 58hp 1600VW motor in a sand rail and went from 12 sec 0-60 to low 5's on 15psi. Torque gains will be hard to come by at low revs because you have to load the motor or rev it to get the turbo spinning. If you're looking for a quick spooling turbo, try to find one that came off of a motor of less displacement than your application. The WRX unit will probably be a lil big for your app.? For plain fun though, a small turbo that spools quickly would be an excellent choice for better streetability.

FUNKYTEE5
 
Mazda MX6 also has a small turbo for their 2.2L turbo engines, as well as a ford probe turbo. I'd check those places, if you want a T3 find a T-bird or an early 80's 300zx (only thing with these is their air cooled, the later 80's models were smaller but water cooled).

also remember a smaller turbo will build boost faster and you won't notice the lag as much. The bigger you go the more lag you'll get and it may not be ideal for offroading.
 
explorer said:
Torque is a measurable value, hp is calculated based on rpm and torque. If the hp increased, at any given rpm, then a torque increase is what made it happen.
Click to expand...
OK professor, yes hp is a component of torque but there are many factors that determine the hp's ability to turn such as crank length. I think everyone on this thread knows that you are looking for torque in 4-wheeling and not unusable hp at the higher rpms. So, for my 2.5l I realized that adding a turbo was not going to significantly increase performance on the trail. It would however make it much easier to get to the trail. I am always willing to add to the thread and am strongly interested in what others have done in hope that someone has come up with a solution for both.
 
There is a bunch of good info over on the street and perormance forum on turbo setups. I kep jumping between a supercharger and a turbo. Boh can be done from junkyard parts but both need fab work and such.
 
HossHoffer said:
OK professor, yes hp is a component of torque but there are many factors that determine the hp's ability to turn such as crank length. I think everyone on this thread knows that you are looking for torque in 4-wheeling and not unusable hp at the higher rpms. So, for my 2.5l I realized that adding a turbo was not going to significantly increase performance on the trail. It would however make it much easier to get to the trail. I am always willing to add to the thread and am strongly interested in what others have done in hope that someone has come up with a solution for both.
Click to expand...

I wasn't trying to be a smartass, just trying to give accurate info. Torque comes from the cylinder pressure acting against a lever arm, the crank. Longer stroke=longer lever=more torque, generally. Anything that increases cylinder pressure will increase torque. From there, higher hp comes along with it. As far as the torque curve, turbos can be set up to provide low rpm torque. Diesels come to mind. I have an Isuzu cabover that uses a 4.75L 4cyl. with a turbo that is very small. I know thats not a technical description of the turbo, and I won't claim to know everything about them. But that engine will make boost, and in fact its peak torque at just off idle.
 
go with the supercharger if your going to offroad it, its going to give you more power throughout your RPM range, where as a small turbo is going to lose its effectiveness at higher RPM's and a larger turbo is going to have to much lag down low to really help you when you need low end.
 
I am about to send in my original 2.5 out of my 85 for a rebuild and am adding alot of performance parts like a stage two cam and lots of other goodies. It is going to cost me about $2000.00 but I think it would be worth it. The guy that will be doing it for me has done one before and got an extra 75 horsepower and 67 more lbs of torque. I don't have the info in front of me but I will have it in about a week or so. The 2.5 is a good motor and has taken everything that I have thrown at it and then some. I would say go with a good rebuild and leave the turbo and supercharger on the shelf.

Kim.
 
85xjwoody said:
I am about to send in my original 2.5 out of my 85 for a rebuild and am adding alot of performance parts like a stage two cam and lots of other goodies. It is going to cost me about $2000.00 but I think it would be worth it. The guy that will be doing it for me has done one before and got an extra 75 horsepower and 67 more lbs of torque. I don't have the info in front of me but I will have it in about a week or so. The 2.5 is a good motor and has taken everything that I have thrown at it and then some. I would say go with a good rebuild and leave the turbo and supercharger on the shelf.

Kim.
Click to expand...
I'd definatly like to see some ino on your build. I already have been picking up parts when I can such as a mopar cam and such so It will be a stong motor to begin with. I'm playing with a few ideas as far as intakes and such. its going in 2wd street mj so i can do with out low end torque. as for the turbo/supercharger debate the turbo is by far better for my app and even if it was a 4x4 I would still proble lean towards a turbo. the blower is just easier to do.
 
I like the turbo idea...I'll keep watching this thread since it applies to what I run....I could use a little more bottom end if it's possible.
 
I told my mechanic that I am looking for just a little more low end power in the lower RPM ranges. I always run 4lo and with my three speed tranny is is great in the mud and steep climbs. I would just like some more wheel speed at the low RPM's. Once I hit a little higher RPM the motor wants to take off. I rev it over 5000 alot of the time and the motor just takes it. I have developed a small rod knock now but with the mods on the new engine I shouldn't have a problem. I just don't like the idea of a turbo or supercharger. Lots more wear and tear on the engine. It won't last as long.

Kim.
 
as far as the motor not lasting aslong that isn't that big of a concern heck the 2.5 in my DD has almost 200k on it and i just can't kill it. plus a properly setup system and good lubricants and mantince take care of a lot of abuse.
 
REDXJ4FUN said:
as far as the motor not lasting aslong that isn't that big of a concern heck the 2.5 in my DD has almost 200k on it and i just can't kill it. plus a properly setup system and good lubricants and mantince take care of a lot of abuse.
Click to expand...

Yes the 2.5 is a very durable engine but it cannot take alot of higher RPM for very long. I have put my 2.5 through alot of punishment also but after memorial weekend it sure doesn't sound the same and that is because of to much high rpm's. That is why I decided to go with the performance parts rebuild.

Kim.
 
The 2.5 has essentially the same size bearings as a small journal smallblock chevy....and the reciprocating parts are lighter....and the stroke is shorter.. all part of a formula for higher rpm if you can get it to breathe well enough.

With the stroke of a 2.5 the drop dead rpm limit based on a max 4500 fpm piston speed by far exceeds the airflow capability and the rod strenght...not to mention the pucker factor of nailin' 'er that hard.
 
MudDawg said:
The 2.5 has essentially the same size bearings as a small journal smallblock chevy....and the reciprocating parts are lighter....and the stroke is shorter.. all part of a formula for higher rpm if you can get it to breathe well enough.

With the stroke of a 2.5 the drop dead rpm limit based on a max 4500 fpm piston speed by far exceeds the airflow capability and the rod strenght...not to mention the pucker factor of nailin' 'er that hard.
Click to expand...

I am always learning something new about my engine everyday. Thanks for that info MudDawg. In the last few months I have learned more about my 2.5 than I have ever known anything else. Keep the info coming.

I am looking into taking my 2.5 and doing a list of mods to it in my rebuild so I can see what kind of results I will get so I can pass it on to others. Try new things and see what happens.

Kim.
 
I also plan on going with a two-barrel Weber carb for a little better breathing for the engine. I tried to find a different carb with a some better performance but had no luck.

Kim.
 
I used a Clifford 47-4501WH manifold....it's not ideal because the runners are cramped and too short and it has way too much plenum volume... bad for low end torque....It is also set up to use a 390 holley carb (unique bolt pattern) so it needs an adapter...that needed work to clear the throttle linkage....and you are still going to need to modify the power steering mount for it to bolt up.....don't use the 390....too much carb....and it's a pos to begin with (at least for offroad). The 36/32 weber progressive is a good choice if you can get one. The best bet would be to go to EFI, but a major hassle on a 85 model.
 
You must log in or register to reply here.

Similar threads

2
1984 - 2001 specs
Replies
4
Views
2K
2001JeepXJNS
2
Back
Top