turbo chrysler 3.7L (low boost)?? been done?

[turbosocks]

Not really sure if this is the right area for this, but I am looking to do a low boost remote setup on my 4x2 2010 Liberty and both the Jeep and Nitro forums don't seem to have any good input or any real information.

seems like the best place to come is where pretty much only turbo guys come to hang out.

There is ALOT of hearsay that I have received from the Liberty/Nitro crowds so far about pistons failing, crank exploding, etc. but no one with experience or proof. you guys probably know how that goes.

I am hoping there is SOMEONE on here that has done it or at least pondered the idea since the 3.7L came in so many different vehicles (ram, dakota, grand cherokee, liberty, nitro, etc.)

this is quoted from my thread over at the nitro forums.

this is going to be a long post........

I am teh n00b on the forums, but not a n00b to boosting, but was wondering if there has been anyone to turbo the 3.7L yet. I have read a little bit about the now discontinued kenne bell s/c kit, but nothing about turbo.

Here is what i found regarding the kenne bell kit:
http://www.kennebell.net/supercharge...7/libert37.htm

Stock:
210 bhp @ motor
235 ft.lbs @ motor
166 rwhp
193 rwtq

Kenne Bell:
296 bhp @ motor ---------- +86
343 ft.lbs. @ motor -------- +108
235 rwhp ------------------ +69
275 rwtq. ------------------ +82

Thats with a twin screw supercharger. I would THINK that a company like kenne bell would never produce a kit, much less with that big of an increase in power if they had issues with ring lands or anything else. I also would think they would see issues, considering the testing they probably go through with a kit like that.

thats about all i can find to run on as far as if the 3.7L can handle boost or not. The rest of the information I have found or received in posts seems to be mostly heresay, and we all know how that is on the interwebz....

Here is what i know about the 3.7L..
Cast Iron block (closed deck)
9.7:1 compression (not to bad for low boost)
forged powder metal rods (pretty darn strong)
aluminum pistons (cast? my main worry)
MAP sensor (not sure what bar) 5v
returnless fuel system (49psi)
split-pin crankshaft (not the best for stress)


I am looking to push about 5lbs of boost on a t3/t4 turbo using a remote style setup right behind the collector, about midway under the vehicle. I was going to use a small air/air intercooler, and bump up the injectors to compensate for the boost to start. at such low boost levels a step or two colder plugs should be perfectly fine also.

Some concerns: mainly the hearsay around the internet saying the 3.7L is weak. the hearsay regarding the failing ring lands because of how high the top ring is.

Some pros towards boosting: MAP instead of MAF... forged rods... decent compression for low boost.. easy to upgrade injectors.. closed, cast iron block..

Some people say the compression is WAYYY to high for boost, but i would beg to differ. most of the 4cyl communities that are boosting have 10:1 compression or more and have no issues with boosting. For example, the beloved honda guys.. also, the miata crowd (10:1 compression) also are a boost friendly crowd.

I have been involved in the Hyundai scene (yes.. hyundai, lol) for the past 6 years and the Beta (4 cyl. Tib motor) has 10.3:1 compression, cast iron, closed block, cast alum pistons and non-forged rods. They run 10-15psi all day long without issues. I was personally running 8-10psi on a completely stock motor for 20k before i sold it. I now sell turbo kits to other Tiburon owners, and none have yet had issues.

Now i'm not saying just because all the Hyundai, Honda, Miata, etc. guys can boost without problems its the same as the Liberty, I'm just wondering why there is so much hearsay about the 3.7L being so weak if it hasn't been tried much/if at all.


I could be totally off base here, but I'm just trying to find some more information on why everywhere i read it seems taboo to even THINK about throwing a little boost at the 3.7L.

I am really not looking for a 'It can't be done, IDIOT' responses.. It would be nice to have a good discussion on why or why it may be possible and reliable.

[fishcleaner]

Forward Motion (Wilmington, DE) did a low boost/high volume system on a Stratus years ago, he may be able to help, but your looking at some serious fabricating.

[Dusty_Duster]

Forward Motion (Wilmington, DE) did a low boost/high volume system on a Stratus years ago, he may be able to help, but your looking at some serious fabricating.

First of all, I don't recommend Forward Motion for anything. Not only do they take bloody ages to do anything, they are quite rude and unpleasant to deal with.

Second of all, a remote mount turbo (like what the OP is talking about) wouldn't require much fabrication beyond bending and welding pipes.

If this motor has been boosted before via that kit, go for it. But you might want to find out why the kit was discontinued. Was it discontinued because too many engines detonated with it?

My only concern would be fuel management. You can't just bolt on bigger injectors with a rising rate regulator and expect it to run. You could use MegaSquirt as a piggyback system and install a second bank of injectors that only open under boost. Some Vortech kits use auxiliary injectors.

[SebringLX]

Tuning is going to be your biggest problem. I think only one company is even doing NGC4 vehicles, and that's Diablo. However they aren't doing anything for any 3.7L.

The PCM will absolutely freak out on you. Even if you use a piggy back system and/or auxillary injectors as Dusty suggested, the PCM will freak out when it sees boost. Probably a 1.5 bar MAP sensor in there at best. Most piggy backs will clamp the MAP voltage, then you run into dangerous timing levels.

[turbosocks]

fuel management isn't a concern to me. at a boost level of around 5psi the computer might fuss, and it might not. In my past experience, at lower boost levels 5 or less lbs, the computer doesn't have much of a problem.

with a decent rising rate regulator and slightly bigger injectors, things should go together well. also throwing in a step or two colder plugs should do well at the very low boost level.

if things don't go well for an 'un-managed system' I have an AEM FIC here that should do the trick.

as dusty said, the fabrication will be pretty easy with the remote setup. the stock muffler is HUGE and in the middle of the Jeep, so it would provide plenty of space for the system.

I have boosted a handful of cars in the past few years, including one of my own. also had a NSRT-4 at higher than stock boost levels with just upgraded (S2) injectors without further tuning.. still going strong with the new owner 30k later.

I'm not really worried about the tuning aspect of it, as i have it covered either way, mainly wondering if anyone on here may have boosted a 3.7L chrysler before.

Kenne-Bell hasn't responded to me yet regarding why they discontinued, but i doubt they will admit to alot of their customers blowing up their cars as the reason.

There is to much hearsay on the other forums and i was hoping someone with a Ram/Dakota/Liberty/Nitro/Grand Cherokee/Durango/Commander may have dropped by to ask the same thing or show their setup off.

Some people also said that the 3.7L and 4.7L are pretty much the same monster, but from some research theres a key difference from what I can tell which is my main concern.

The 3.7L has a split-pin crankshaft and the 4.7L doesn't(theoretically making it stronger)