Topic: 2.5 turbo question

[l3uckeyefan]

researching cant find much but, i turboed my tj, i need to find out if the aem fic would work with the computer so i can piggy back that to tune.or if any one else has an idea, no one seems to know much about it, not many people turb the 2.5 any help, much appreciate it

[l3uckeyefan]

whats up all, im new to this forum and its the only one i could find with my topic. well i turbed my 99 tj with the 2.5, my problem is i need to get something to where i could piggyback my computer so i can tune. didnt think much about it during the project. I have been looking t the aem fi/c, but know buddy can tell me if it will work or not, and i dont really wanna spend the $400 bucks and it not be compatible. any answers or suggestions i would appreciate it.

[l3uckeyefan]

hey all new to the forum and i am hoping some of you guys have answers, I believe so with the fact you have the turbo thread.well to start I have a 99 tj with the 2.5 motor. just put a turbo on after I had the motor completly over hauled the complete motor. port, polish, angled and so on. I have bigger injectors and a walbro 255 fuel pump. my question or need help with is. I need to find a product that will allow me to piggy back my computer, so I can have it properly tuned, I have been looking into  the AEM fi/c ?. any suggestions or comments would help nobody in town has ever tuned a jeep or anything like it. I have one shop where they specalize in supras they told me they can help but not positive with the out come

[sharpxmen]

researching cant find much but, i turboed my tj, i need to find out if the aem fic would work with the computer so i can piggy back that to tune.or if any one else has an idea, no one seems to know much about it, not many people turb the 2.5 any help, much appreciate it

there are quite a few good threads in here regarding turbos.
I'd say read Sean's turbo project here http://4bangerjp.com/forums/index.php/topic,3560.0.html and also other ones by using the search to find some more on this site

and if you're interested how the boost changes the way an engine works and what the minimum requirements are once you start pushing more air in your cylinders you can have a read at this http://4bangerjp.com/forums/index.php/topic,7292.0.html (this one was started by a member asking questions just like you did, so no reason to post all that all over again, if you still have questions after lecturing these 2 threads  i suggest to start a thread where you can ask specific questions or clarifications - it is hard to answer something so general). good luck with your build.

[l3uckeyefan]

no i understand the mechanics of the motor the problem im running into is how to properly tune it. i have the larger injectors, fuel pump all that im just having a problem finding the hardware to piggyback the system. what i want to do is get it on the dyno and get the  gliches out, yet i do understand there are not many of these out there , and fewer shops that will touch it

[sharpxmen]

the hardware you need and the options you will find mentioned in those threads

[l3uckeyefan]

yea so maybe I dont see it but there is not an actual product in either of those threads to where i can piggy back my computer to have tuned/dynoed I dont know. Im not sure if you can point me to that actual information. appreiate it

[sharpxmen]

yea so maybe I dont see it but there is not an actual product in either of those threads to where i can piggy back my computer to have tuned/dynoed I dont know. Im not sure if you can point me to that actual information. appreiate it

Look for split second PSC1 or FTC1. I recommend you get the one that also has the O2 voltage mod (not sure if PSC1 has it, some of the FTC1 ones do have it). You can call them, they are very helpful and will sell you the right product with a base fuel map based on your engine and boost level but you will need to fine tune your engine setup. The product comes with clear connection instructions so you could install it and tune it yourself, their website is http://www.splitsec.com/ but you will not find information about your Jeep in there.
You will also find a good tuning document on the site that explains how to tune your engine once you have a piggyback system installed, i know you said that you know all that part but it is a good read anyway http://www.gadgetonline.com/U-Tune.pdf

Since yours is a 99 you might want to also look at maybe reprogramming your stock ecu, but i have no experience with that or if it can be done on your model of Jeep since mine is a 95 - Kenne Bell does (or did) reprogram the TJ 6 cyl ECUs for their s/c kits, so considering that i assume it can be done on yours as well, not sure if a DIY solution is available though but that means you can go by w/o a piggyback system (which if i had the option is what i would go for, or be my first choice if you wish - but with the piggyback the nice thing is that you can switch to stock w/o the need of an extra ecu or reprogram it back to stock)

I think Avenger and Rimmer recommend the use of the Split Second unit, in Rimmer's case they also recommend changing the AIT sensor location ahead of the compressor.

[l3uckeyefan]

thanks sharpxmen, that is what i was looking for i actually found that a minute ago, im going to look into it, out of curiosity sounds like your very knowlegble with this stuff have u heard of usins an AEM fi/c i like the product and capabilities but from what i have read they are universal but no one has commented on it but then again i havent found a forum with such knowledge and info about the turbo 2.5 jeep. and your right u guys are pretty prompt. thanks again

[l3uckeyefan]

oh one more question i went with accel 44ib fuel injectors, seems like iam duping to mush fuel to piston,from your post in the historylooks like those are way to big should i bring them down.

[sharpxmen]

what boost and also what pressure. Are your accels rated at 44lb/hr@43.5psi? - in think in your case your Jeep runs at 49psi rail pressure so you will dump even more than 44lb/hr - i think the result would be appropriate for a 300 HP engine if not more (at 49psi they will flow 47lb/hr and if you account for the boost that will increase your fuel rail pressure as well thru the vacuum port of your fuel pressure regulator those injectors will have a wopping static flow of 49.5lb/hr). so i would say that you're right, you need a better choice in injectors. Make sure when you pick the next set you calculate that based on your target fuel rail pressure, the ones you have are so big that there is no point in even trying to lower the pressure to get them to the right flow, the press would be too low and the fuel won't atomize properly. There's a link in the other post i mentioned to a thread where i explained how to calculate the flow based on pressure (if you want to have a look at it this is it http://4bangerjp.com/forums/index.php/topic,7203.0.html) - i made an excel spreadsheet where i put the values in and get the results so in your case i got this (i assumed you'll be using 6 psi just for an example)
Old flow (lb/hr)   | old psi   | new psi   | New flow   | boost   | new flow (with boost)
44                    | 43.5     | 49           | 46.70        | 6         | 49.48

- in case you want to make your own little calculator in excel the cell id for the old flow in that spreadsheet is C3 and the formula for the new flow is =C3*SQRT(E3/D3) . E3 is the new psi, D3 is old psi and so on, G3 is boost and the formula for the flow with the new fuel rail pressure + the vac/boost reference adjustment by the fpr is =C3*SQRT((E3+G3)/D3) - there are also a few interactive ones you can find on the web (search for injector flow calculator or something like that).

always keep in mind that you will increase your fuel pressure aproximately by the amount of boost thru the vac port on your FPR. 

[l3uckeyefan]

would u have any recommendations for injectors and yea they are 44lb/hr@43.5 psi. im stumped on this fueling problem. i can wrench,weld whatever but this has got me. i have several performance/import shops and no one has ever seen nor worked on a jeep like mine.

[sharpxmen]

thanks sharpxmen, that is what i was looking for i actually found that a minute ago, im going to look into it, out of curiosity sounds like your very knowlegble with this stuff have u heard of usins an AEM fi/c i like the product and capabilities but from what i have read they are universal but no one has commented on it but then again i havent found a forum with such knowledge and info about the turbo 2.5 jeep. and your right u guys are pretty prompt. thanks again

not familiar with it, post a link and i'll have a look maybe later tonight and give you my 2cents on it.

one thing i forgot to mention is open and closed loop - that's why i suggest you look for the one with the O2 mod - when your ECU is in closed loop it will not matter what your piggyback map output will be, your ecu will try to go back to 14.7afr based on O2 feedback and will be too lean when in boost - in case the choice is to reprogram the stock ecu usually the new fuel map (table) will take it out of closed loop sooner. Since you are OBDII you have the advantage of monitoring the open/closed loop state and fuel trims with a laptop which is great option for tuning.

[sharpxmen]

would u have any recommendations for injectors and yea they are 44lb/hr@43.5 psi. im stumped on this fueling problem. i can wrench,weld whatever but this has got me. i have several performance/import shops and no one has ever seen nor worked on a jeep like mine.

need boost and fuel rail pressure to make a guess (again would be a guess). I recommend also to use an adjustable FPR so you can tune your injector flow.

this is a link for the injector flow vs horsepower calculator http://www.injector.com/injectorselection.php
use 0.6 for BSFC and the target horsepower based on your boost - for the horsepower use your target max boost but be conservative and account for losses (to calculate your target horsepower you can use this formula NewHP=OldHP*(boost+14.5)/14.5 but take off about 5 to 10% out of the final result as you will never get it right on the money.

the result you will get from the link above is the requirement of fuel in lbs per hour for a certain horsepower output. from there you take the output of in lb/hr, use your fuel pressure as the old psi (keep in mind to add the boost to it if your FPR has a vaccuum port) and 43.5psi as the new pressure - you will get the result of what injectors you need at standard fuel pressure, so if your final result is 32lbs for example you will want to get something that is manufacturer rated at that flow for 43.5psi (some are rated at different pressure based on the vehicle they are installed on).

EDIT: by using that link above your accels are suitable for a 300HP for a normally aspirated engine (0.5BSFC) and in case it is a forced induction you can support something like 285HP at around 14.5psi boost/2bar absolute pressure (very approximate boost value though using 150HP as the starting point).

[l3uckeyefan]

yea, im fing stumped im going to take it to a friend see what he thinks. appreciate the help. let you know how it goes