Supercharger Rebuild

[cnidy1230]

supercharger rebuild

My name is Chris and I am new to this cite, so hello all. I plan on puting a custom super charger onto my 92 XJ with a I6 4.0. The supercharger is off a 00-04 nissan exterra. I have another engine in the garage and plan on building it up but still not sure about stroker engine. main problem is i have the stock AW4 and cant find upgrades for this. thought about th350 upgrade with advanced adapters help. still not sure that is the way i want to go any help/advice would be great.

 

[Beej]

Re: supercharger rebuild

My name is Chris and I am new to this cite, so hello all. I plan on puting a custom super charger onto my 92 XJ with a I6 4.0. The supercharger is off a 00-04 nissan exterra. I have another engine in the garage and plan on building it up but still not sure about stroker engine. main problem is i have the stock AW4 and cant find upgrades for this. thought about th350 upgrade with advanced adapters help. still not sure that is the way i want to go any help/advice would be great.

This thread will likely be moved to the street/performance forum. There is a lot of info in there regarding boosted 4.0's. The AW4 will comfortably handle 400hp, so unless you are shooting for something beyond that, you'll have no problems. (Other than a blown motor ).

For performance enhancements on the AW4, check out Level 10 Performance...

http://www.levelten.com

 

[5-90]

Re: supercharger rebuild

The AW4 was designed by Toyota, and is used in their RWD Van, automatic Pickups, and the Celica and Supra (yes, the turbocharged version of the Celica.) It's also found in some RWD Lexus applications.

Why is this important? It helps to open up the field...

I believe Level Ten (Google them, I don't recall the URL) offers some upgrades for use with the 03-40/AW4 slushbox, so that should be a good starting point.

As far as the blower itself, can you be more specific? I know you said it's off of a late Xterra, but does it have any "maker's marks" on it? I'd be almost willing to bet it's an Eaton or a Whipple - or a knock-off of either one. Most "two-rotor" blowers are fairly simple devices, but I'd hate to give you bad info...

Meanwhile, welcome aboard, and I hope you learn a lot!

5-90

 

[cnidy1230]

Re: supercharger rebuild

I beleive it is an Eaton. i saw a post on this cite saying the AW4 will handle 400hp and that gave me hope to keep it. the supercharger runs about 6 psi stock so that will give me around 350 hp if i run a stock engine.

 

[Beej]

Re: supercharger rebuild

Well, not quite 350hp. More like about 260-270hp...

 

[cnidy1230]

Re: supercharger rebuild

right, sorry wrong calculation

 

[5-90]

Re: supercharger rebuild

350hp may be a little, er, "optomistic," but here's a rule of thumb...

Take the peak power output of the engine.

Take the boost you're going to feed it (in atmospheres.) Add one. (for instance, a 6psi boost would be 6psi/14.7psi, or ~.4ATM. 1.4ATM total.)

Multiply the output figures times the number you get from the second step above. Figuring, say, 200bhp for peak output, that means 200bhp x 1.4 = 280bhp

Granted, this is horribly over-simplified, but it should serve to give you an idea. It's also optomistic in itself, since it does not account for adabiatic efficiency of the blower, charge air cooling greatger than 100% (charge air ends up cooler than ambient temperature,) parasitic drag, or any of a number of other factors, but it's a good ballpark to work from.

Once you start to firm up your numbers, you can then run a simulator (Desktop Dyno or similar) to get a better estimate.

Also, bear in mind that, just beacuse the blower makes 6psig boost in its original setup, doesn't mean the same setup is going to make 6psig for your engine. I'd be willing to bet it came off of an engine with a smaller displacement (lowering the effective boost,) and that the crank/blower pullys will also need to be changed to maintain boost. There's a lot more to supercharging an engine than just sticking on a blower... However, a lot of us are willing to help you.

While we're on topic, I am going to move this to "Street and Performance" - since it more properly belongs there - and thank Beej for saving you Googling Level Ten (I couldn't recall the URL offhand, and didn't want to post a dead link...)

5-90

 

[Beej]

Re: supercharger rebuild

Jon's right on (as usual). I just researched that supercharger you've got and if it is indeed from an XTerra, its an Eaton, Roots-type, but unfortunately its only rated at 3.5psi of boost on the XTerra. Assuming those numbers transfer to the XJ 4.0 (which they probably won't exactly), that's going to give you about a 24% increase, or around 235hp.

Assuming you can get more boost out of it though, it should be good to go. From what I've read here, I don't think you can put more than about 7psi through the 4.0 without some significant internal mods...

Hope this helps...

:thumbup:

 

[cnidy1230]

thanks again, I looked at the wrong figure on my paper. This will be my first blower install and first fuel injected engine rebuild. I am used to building big horse other ways with a carb engine. I have found alot of good info from the Internet on things to check for and prepare to do.

 

[Beej]

It should only be a matter of a few swapped out parts for more boost though. I bet you'd get some good info by contacting Eaton directly.

 

[5-90]

Re: supercharger rebuild

Jon's right on (as usual). I just researched that supercharger you've got and if it is indeed from an XTerra, its an Eaton, Roots-type, but unfortunately its only rated at 3.5psi of boost on the XTerra. Assuming those numbers transfer to the XJ 4.0 (which they probably won't exactly), that's going to give you about a 24% increase, or around 235hp.

Assuming you can get more boost out of it though, it should be good to go. From what I've read here, I don't think you can put more than about 7psi through the 4.0 without some significant internal mods...

Hope this helps...

:thumbup:

Getting more boost is usually a matter of selecting pullys with more overdrive to them (smaller snout pully and/or larger crank pully.) This will change the drive ratio at the blower snout.

Also, what displacement was the engine that it came off of? That would generate a significant correction, as I'd mentioned (fixed-displacement blowers generate boost based upon the amount of air they can feed related to the basic air movement of the engine they're bolted to.) Isn't the Xterra engine somewhere around 3 litres? That means a 30% reduction in boost, before anything else is accounted for - simply due to the larger displacement of the AMC242.

Eaton pullys, however, should be fairly easy to find - and any competent machinist can make them on a lathe, if it comes to that! You may still run into a ceiling based upon the model of the blower you're dealing with (Eaton fields four for production vehicles, as I recall. I should have compressor maps around here somewhere...) and you'll really need to know! The difference between the four is the basic displacement - the amount of air each blower should move per revolution. I was originally looking at, I believe, the second largest Eaton - until I got into Whipples (increased efficiency, don't need to run them as fast, increased thermal efficiency) and I've been working on ideas for a Whipple and a fabbed intake...

5-90

Oh - and contacting Eaton directly may not work. Try Magnuson Performance first - but you're probably going to end up having to get a few things made. I'd also say try contacting Kenne Bell (since they do the Whipple kit for the TJ,) but they don't mod the intake manifold, and there would be some hood clearance issues putting a blower on top of the intake and trying to close the hood - the KB TJ kit comes with 1" pucks for a body lift...

 

[cnidy1230]

the easiest way to increase boost i found is pulley size. many people have done it on the exterra and i guess get a good increase in boost. i will see, alot of brackets and fab work to do still. still in the research stage of this project.

 

[Beej]

Keep us posted...

:wave:

 

[cnidy1230]

clearnce i can do. already started and almost done with an 8 inch cal hood. i beleive a 3.3l is in the exterra. already sent an email to magnuson since they do most everything for eaton. i gained alot of info from kennebell to help so far. I have availability to a machine shop so I can make about anypart I would like to. as long as i know what i need. i beleive it is a m62 from eaton but have not comfirmed it yet still working on that.

 

[5-90]

the easiest way to increase boost i found is pulley size. many people have done it on the exterra and i guess get a good increase in boost. i will see, alot of brackets and fab work to do still. still in the research stage of this project.

Correct - what you're doing is changing the ratio of crank drive speed to snout driven speed - and you're usually driving it faster to make more boost.

We do have an advantage in that the AMC242 actually likes being run at relatively low crankshaft speeds (mine lives at about 2800rpm!) and that means you're probably not going to end up "overdriving" the blower. However, since it's also a relatively large engine (over 200cid,) you may just want to think about getting the next size larger blower - like the Eaton off of a T-Bird or a Bonneville (~3.8 litre V6, should be the next blower up from that on a ~3.0 litre V6. 230-ish cubic inches, vice 170-ish.)

Also, the headache you tend to run into at higher boost levels (higher speeds) is "internal leakage" - where the compressed air actually ends up leaking backwards past the rotor tips and ends. This is a variety of "parasitic drag" that you may end up having to account for - and why it's better to use a larger blower, driven slower; than to use a smaller blower, driven faster. Ditto pretty much anything - always remember, TANSTAAFL ("There Ain't No Such Thing As A Free Lunch" - Robert A. Heinlein, The Moon is a Harsh Mistress.) You have to be ready to trade one thing for another - the more you want, the more you have to trade.

I'd be perfectly willing to help you figure out how to get where you want to go - I've got most books on performance at hand (including one I wrote myself!) and I've got some decent sim software and I've already done most of the research into performance parts for you. Frankly, I'd have damn near killed to have someone like me handy when I was building bracket engines, and had to figure all of this stuff out on my own! You can't get too much help or too much information on a project like this - you can aways just write it down for another project if you don't end up using it for this one. That's how I learned most of what I know...

5-90

 

[cnidy1230]

back to tranny. ya'll say that most parts for the celica, supra.... toyata stuff will fit? how will i know for sure? have you seen anything to build more line pressure like some auto deisel trannies offer?

 

[Beej]

BrettM at Awshifting.com makes some neat toys for the AW4...

 

[cnidy1230]

I see what your saying, that internal leakage will also boost temp if I remember right. wich is no good. will keep this in mind.

 

[5-90]

I see what your saying, that internal leakage will also boost temp if I remember right. wich is no good. will keep this in mind.

Correct - you'll get temp climbs from compressing the air (Boyle's law, or was it Pascal's? It's been a long time since high school phyzzies) and from the friction you get from leaking air (it's not much, but it's certainly there!) The bulk of the temperature increase will come from compression - that's why turbos usually run charge air cooling (commonly known as "intercooling") due to the higher boost levels you get. The point of diminishing returns for running boost without charge air cooling is, as I recall, 7.35psig (or 1/2 ATM,) but effecient cooling will always help - anytime you cool the air charge, you make it denser. Denser air = more air for a given volume = ability to burn more fuel = potential for more power.

As far as the line pressure increases, I'd start by checking with Level Ten. I haven't had to look into doing it with the AW4 so much - and when I was doing this sort of thing regularly, I was working with cast iron Powerglides, THM350/400, C4/C6, and A727 (none of which are anything like the AW4 inside!) I tend to prefer manuals anyhow - you just find a clutch shop that can put stronger spring packs in the clutch cover, and call it good.

5-90

 

[cnidy1230]

thats why I am here cause I am used to the C-6 or manual trannies. i can rebuild them but not sure what to do with this thing. lol good thought about the clutches, ya'll think AW4 is pretty good it sounds like so unless I really go big I think I can make it work.