Jeep 4.0L + turbo

[czb83]

Hello, first post here(just found forum after searching for turbo jeeps). I've been researching on how to turbo my Jeep cherokee with a 4.0L I6 engine. I saw a few post regarding turbos and Jeeps, so thought this might be a good place to ask for help. I've already researched fuel/ignition, and decided on MegaSquirt, which I am currently tuning. Ive actually drove around town, but there a couple bugs left(wiring issues).

Anways, I've been trying to decide on a turbo, but there so much variations on turbos its seems, that its hard to pick one. I've followed the guides, but was wondering if someone here might be able to help. Heres some calculations I have done.

(CID × RPM) ÷3456 = CFM

(242 * 5250) % 3456 = 368 CFM

368 * .85VE = 313 CFM

(10 + 14.7) ÷ 14.7 = 1.68:1 pressure ratio

T2 = T1 (P2 ÷ P1)0.283 = temperature rise

T1 = 80F + 460 = 540R
P1 = 14.7psi
P2 = 14.7psi + 10psi = 24.7 psi

T2 = 540 (24.7 ÷ 14.7)0.283 = 625 R

625R -460 = 165 F inlet temp ideal

165 - 80 = 85F increase

Ideal Outlet Temperature Rise / AE = Actual Outlet Temperature Rise

85 / .7 = 121F actual outlet temp rise

80 + 121 = 201 °F Actual Outlet Temperature

(Inlet °R ÷ Outlet °R) × (Outlet Pressure ÷ Inlet Pressure) = Density Ratio
(540 ÷ 661) × (24.7 ÷ 14.7) = 1.37 Density Ratio


Outlet CFM × Density Ratio = Actual Inlet CFM
313 CFM × 1.37 = 429 CFM Inlet Air Flow
429 * 0.069 = 29.6 lbs/min

Anyways, the calculation i did here is for 10lbs of boost. I'm making about 200hp stock, i'm looking for about 300. 10lbs boost = 1.68PR which would equal 36.3 lb/min of flow, but I did calculations for air temps and found PR to be 1.37(wow!). So when looking at a flow map, do I plot 1.37 against 29.6lb/min(from calculation with temp increase). 1.37PR = about 5lbs boost. Originally i plotted 1.68 against 36.3, but that was without air intake calculations. Does this mean I have to choose turbo that produces more boost than i want, because after air expansion, it ends up being less?

In the calculations above, it put in 10lbs boost, i end up with DR of about 5lbs of boost. Alright, I think i'm confusing myself now. Anyways, after doing these calculations, a t04B 60-1 trim looks perfect. Does this look good, or are my calculations wrong? Should I take into account intercooler when choosing one, because it would lower temps, and my turbo wouldnt have to flow as much to get same power, or is that completely wrong?

Phew, that was long first post. Well, I'll take advice I can get, as I'm a little lost right now.

Thanks

[Frank]

Welcome!!!!

Good job on working the equations. I could have saved you a lot of math, but math is good for the soul! Anyway, I have a turbocalc you maybe interested in. It is web based and free and is the best one on the net. http://www.squirrelpf.com/turbocalc/index.php. Taking a stab at what you want, I would click on the below link for what I have already filled out for you. In addition, below are some turbo suggestions.

So if you are going to upgrade your exhaust, put a good intercooler in, and clean up the intake and exhaust tracks, you could expect the following. In addition, your calcs are pretty dang close to mine. I came up with 7.7psi of boost. I used some dyno plots of 4.0L jeeps to come up with your power range and VERY rough VE. But it should be dang close!

CZB83's Turbo Config

In my opinion, you are going to want a smaller turbo then normal because you dont want to sacrifice your low end torque, especially if you take it off road.

T04E 57trim - If you seriously go off road with it, then most definently put a T3 exhaust section on as a StageIII. That would be quite boosty too. No lag. If you want full exhaust, keep it stock wheel, dont upgrade the exhaust to any stage.



There are others, but there isnt much justification to them as they are alot more.

[czb83]

Wow, thats a pretty good tool. Thanks, as that should save me some time.

I was playing with tool, and I think I found something that looks very good. I plotted it against a t04b H-trim and the red dots fit within the high efficiency regions better than any other turbo map I have looked at. Also, looking at the bottom cut off line is much lower, which is the flow at which is produces minimum boost right?

I was planning on getting a rebuilt garrett from blaast performance. I found they have two h-trim t04b's, one with t31 hotside
http://www.blaastperformance.com/index.php?p=t31t04bh
and one with t4 hotside
http://www.blaastperformance.com/index.php?p=t04b-htrim

Then i started looking at t04e turbos, and found that the t04e 60 trim looks like it would get me boost with greatest efficiency, just the minimum boost line is higher than t04b H-trim. I found that one too
http://www.blaastperformance.com/index.php?p=t3t04e-60
which is stage 1, they have a stage 3 for more $$, but I'm not even sure on the difference. How can i figure out what hot side I need?

Anyways, that calculator really is helping this progress. What do you think on my turbo choices? If I can't find an intercooler, will my choice of turbo change?

Thanks

[Frank]

Umm. You need to have an intercooler no matter what. It is just to hot. If you dont, then you will have reliability issues. The T04B H-trim does look good. I would get it with a StageIII T31 side as you found.

I would however change your source of buying the turbo. You can get the turbo. For the same price, you can get it from Turbos Unleashed who is a vendor on this site. They are a very good vendor with good warrenties.

As for intercooler, I know that one of our Turbo Jeep guys was using the NPR and it fit very well.


Frank

[czb83]

Will do on the vendor, his prices look pretty good. I'm now leaning towards the t04e style turbos as they seem more efficient. Space is tight, so I was leaning towards to4b, but it may still work. the 57 trim seems out of place when comparing flow maps. the 54 and 50 trim look they fit very well as I compared different power estimates. I changed the config to have max boost by 2500 rpm, is that unreasonable? Also, this is not an offroading Jeep, so keep low end is not extremely important. I'm just doing this as a fun project to give me fun to drive.

http://www.squirrelpf.com/turbocalc/...uct=5calc=yes&

[Vigo]

one thing about off-roading is the last thing you want is a sudden surge of power to send you into a tree or off the trail. low rpm boost would be detrimental to off-roading in my opinion. the 4.0 in low range is more than enough to take a 4000 lb jeep up a 50 degree incline as long as you dont want to go more than 5 mph (if you do you're insane). keep us updated and post something up about your megasquirt in the electronics section!

[Frank]

Will do on the vendor, his prices look pretty good. I'm now leaning towards the t04e style turbos as they seem more efficient. Space is tight, so I was leaning towards to4b, but it may still work. the 57 trim seems out of place when comparing flow maps. the 54 and 50 trim look they fit very well as I compared different power estimates. I changed the config to have max boost by 2500 rpm, is that unreasonable? Also, this is not an offroading Jeep, so keep low end is not extremely important. I'm just doing this as a fun project to give me fun to drive.

http://www.squirrelpf.com/turbocalc/...uct=5calc=yes&

Cool. I think any of those turbos would work well. I think a full T04E exhaust housing would then be in order. It will give a good clean climb in power. I would say it should be very close.