Topic: Anyone knows of any parts off of other motors that will increase performance?

[countryboy15]

Does anyone know of any parts off of other motors that will increase the performance of a 2.5 L '91 YJ? I know about the 4.0L stock air intake system and the 4.0L thottle body. I was just wondering if there were any other cheap junkyard mods like this that I could do to my YJ. I have heard speculations about swapping the intake manifold, off of the newer 2.5 L TJ , onto a YJ 2.5 L but haven't read about anyone doing this.

[FourbangerYJ]

The FAQ -> -> http://4bangerjp.com/forums/index.php/board,11.0.html has a lot of info your looking for. E-fan and injectors and gearing info.

[countryboy15]

I already decided on the alternator setup. I already have the e-fan.  I have a custom air intake, throttle body spacer, and a 4.0L throttle body, I dont know which injectors to go with. The FAQ doesn't speak clear to me since I dont understand what it is talking about. I need help on understanding this.  The gearing stuff is something I know about and I doubt I will find 4.88 geared axles off of another vehicle in a junkyard, any advice on this? So I take it there is no other mods that can be done to a 2.5 L YJ with parts off of other vehicles. thanks for any help.

[bumati]

Alternator setup?

[countryboy15]

Alternator setup?

The 136 amp alternator off of a 2001-2005 jeep grand cherokee is which one I was referring to.






Which fuel injector to go with? I tryed to look the FAQ theard (about the fuel injectors) over again. Now I am worse off than I started and am now even more confused about fuel injectors. I have a wrecked 4.0 L '91 jeep wrangler, will the fuel injectors off of this jeep work on my 2.5 L '91 jeep wrangler?

[sharpxmen]

Which fuel injector to go with? I tryed to look the FAQ theard (about the fuel injectors) over again. Now I am worse off than I started and am now even more confused about fuel injectors. I have a wrecked 4.0 L '91 jeep wrangler, will the fuel injectors off of this jeep work on my 2.5 L '91 jeep wrangler?

91 4.0L injector flows 21lb/hr, the stock 2.5L is 17.4lb/hr - 20% increase in flow so at wot your afr will be 20% less - will result in something below 12 afr which is way to rich (i think will be close to 11) - your mpg will be hurting bad and you'll be smoking black quite a bit (again, this is at wot when the pcm is in open loop with no o2 sensor feedback).

[countryboy15]

S

91 4.0L injector flows 21lb/hr, the stock 2.5L is 17.4lb/hr - 20% increase in flow so at wot your afr will be 20% less - will result in something below 12 afr which is way to rich (i think will be close to 11) - your mpg will be hurting bad and you'll be smoking black quite a bit (again, this is at wot when the pcm is in open loop with no o2 sensor feedback).

Then which fuel injector is recommended to go with? The fuel injector FAQ confused me even worse than I already was. From what I am getting, The Stock Ford Mustang 5.0L and the Ford explorer V8 are the ones to go with, but is there any specific years to look for the specific fuel injectors in these vehicles and what is the part numbers that I need to be looking for? Thanks for any advice.

[neale_rs]

Does anyone know of any parts off of other motors that will increase the performance of a 2.5 L '91 YJ? I know about the 4.0L stock air intake system and the 4.0L thottle body. I was just wondering if there were any other cheap junkyard mods like this that I could do to my YJ. I have heard speculations about swapping the intake manifold, off of the newer 2.5 L TJ , onto a YJ 2.5 L but haven't read about anyone doing this.

Yes, all the parts from a Chevy V8! 

[countryboy15]

that would be nice but dont have the money or knowledge to do this since I am 16.

[neale_rs]

I know you mean to do something else     but your age is not really an impediment.  Regearing will do the most for you although it can be costly.

Good luck with your project.  This reminds of my first one with a '43 GPW, it was awesome having a Jeep at 16.

[countryboy15]

I was just wondering if there was any little small thing that would give my jeep a little more peep like the 4.0L throttle body did.

[sharpxmen]

Then which fuel injector is recommended to go with? The fuel injector FAQ confused me even worse than I already was. From what I am getting, The Stock Ford Mustang 5.0L and the Ford explorer V8 are the ones to go with, but is there any specific years to look for the specific fuel injectors in these vehicles and what is the part numbers that I need to be looking for? Thanks for any advice.

a few things need to be considered when choosing an injector. the ones you see referred to as 19# injectors are actually 18.4lb/hr (or something like that) but the pressure at which they are rated is 43.5psi. your YJ runs at 39psi - the resulting flow is less than stock if you install those injectors. They are also a different type, the design III have 4 holes and are disc compared to pintle on the stock ones (design III are better than stock). if your goal is more power you need to look for an injector that flows between 5 to 10% more than the stock ones so your result is reasonable and not flooding the engine with fuel. the alternative is an adjustable fuel pressure regulator, hesco makes direct fit ones - increasing the fuel pressure will increase the fuel delivery at wot (wide open throttle). for best results a combination of the 2 would work, design III injectors and and adjustable FPR. i don't have an injector p/n that i know for sure will give you the result you're looking for just by itself but you can research and use an online injector flow calculator (google that) to determine the resulting flow on the YJ fuel pressure.