Anyone ever thought of using an Eaton M90 Grand Prix roots type blower for a custom SC setup? Searched around and it seems everybody and their grandmother is going that route (especially 5.0 guys). Also looks like the M90 is very reliable (often no rebuild for 120+K).

 

Personally I would take one over a centrifugal style supercharger due to the low end response of the positive displacement design however, they are terribly innefficient.

They technically aren't compressors... they're simply blowers. The roots style just blows so much air into the intake that the air actually compresses in the intake. (Screws s/c's and centrifugal compressors (both turbo and s/c) are true air compressors as they compress the air themselves.)

Being that its not a compressor is the reason why it is so inefficient. Its creates a lot of heat as well. The roots style s/c's also tend to not keep full boost to redline. From what I've seen, some will some won't.

The good things about them is you get nearly instant boost, they're quite low cost, there are tons of them around, and as you mentioned they're quite reliable.

The downside of putting it on a Maxima... its only been done once before (to my knowledge) and there will be a lot of custom work to get it in.


Personally, I'd go the turbo route as they're very efficient and can make a lot of power. If you want to go positive displacement the best route for that is actually a screws s/c (Whipple, Lysholm, etc). The new Whipplechargers are actually very efficient and have all of the benefits of a roots s/c except for the price. They tend to be quite expensive but if you can get your hands on one for a good price that'd be the way to go s/c wise.

In the end its up to you though. If you want the low end response of a positive displacement s/c, that's your choice. You'll just have to put down the money and work to get it all done.

Good luck with whichever route you choose.

 

I don't think it is that hard to get done. It would require a custom upper intake manifold (which I was already planning on doing whether I stayed N/A or not) and an intercooler, both things that the Vortech kit made for us does not require. But on the flip side, the HP/$ ratio is very interesting. I just started looking into this and I'm amazed how cheap a good setup can be built (if you do the fabing yourself of course).

Looking at my engine bay, you take off the upper IM of the 3.5 and you have a perfect spot to mount the blower. I would need to fab a passenger side motor mount for the belt to pass though, but still. Welding/fabrication is not a problem.

I wouldn't say they are inefficient. GTP guys are putting down real impressive ET's and Trap speeds considering they weight 3500+, and their dyno numbers are even deceiving for what they trap. The opposite is true for centrigugial SC'd maximas and 350z's (IMHO). I think area under the curve has a lot to do with that vs the peaky powerbands of vortech SC'd VQ's. I see SC'd 3800's putting down only 350/380 to the wheels and trapping 117-118 mph at 3400-3500+ lbs raceweights.

 

Craig Mack did this a while ago, his design was fabricated like the Acura CL Sc'er kit with the crossover piping though.

 

Is he still around?

He used a shaft, cross-engine bay (up front)? I was trying to eliminate that.

EDIT: Like that?

 

yes thats the style of setup he was running. He doesnt come around here anymore but you might be able to find him lurking around any Lightening boards.

 

This is the route I would like to go in the future. Craig Mack did his using a crossover, but I'd like to go with JClaw's idea of mounting it in place of the upper intake manifold. This would require an adapter, though. I think this would be more effecient, less space-consuming, better-running, and cheaper than Craig's setup.

All the problems that Craig's setup would be addressed in a setup like this, as well.

EDIT: What gave me the idea was that the 3800SC crowd is pretty large locally, and one of my buddies has 2 GTP's, and does all kinds of engine swaps for people and the like, so he's got M90's laying around everywhere. Last time I was there working on my car, we test fit an M90 in the engine bay. I sat it in the crevice between the upper intake manifold and the front valve cover to give me an idea of whether or not it would clear the hood, and it's no taller than the upper intake manifold. That's a pretty good estimate, too, because it was sitting about where it would sit if there was an adapter sandwiched between it and the lower intake manifold. The only real issue was the snout, which was not long enough. Atleast the 3800 gen 3 snout wasn't long enough, the snout from a an older Thunderbird M90 may be long enough, but if we need exact lengths a custom one would probably be less work.

EDIT 2: For the best results, you'd want a gen 5 blower. The gen 5 came on the 2004+ GTP (and current GT, since it was renamed). It is ever so slightly larger, and a popular cheap upgrade for the 3800 guys. Personally I would probably go with a gen 3 though, simply because I could get one for next to nothing, if not free.

 

you guys forgetting about hood clearance?

 

I addressed that. Read my first edit.

 

IMO its going to be a lot more custom work than you guys are making it out to be. Good luck if anyone decides to do any of the work instead of just talking about it.

 

I'd jump right on it if I had money. At the current time, though, I don't...and I need to get other things out of the way first like a y-pipe. I have to save for Maxus, too

 

Well if you can get one for next to nothing... let me know

Someone is selling his for 400$CND (about 350$US) on our local forums. It's from a 1998 and comes with the intake manifold. I'll probably go with a GEN III and upgrade when my wallet is fatter.

How much of a difference does Gen III vs Gen V make?

How "cheap" is cheap for a Gen III--Gen V upgrade?

About 7 inches of hood clearance above the rear head where the upper intake manifold sits. Enough. The 2k2 IM is pretty damn big and tall.

 

When I say next to nothing, I mean like $100 or so. If I got one for that price, though, I'd need to change the oil in it and little stuff like that. These are not rebuilt ones I'm looking at, merely ones in good working condition. $400 is a bit much either way you look at it, though, unless it's been rebuilt recently.

I can't give you #'s on Gen III vs. Gen V. I only know from hanging around those guys that it flows more because it's slightly larger (look at a picture comparing the two, you'll see what I mean) and that it's a popular upgrade for them because they just buy them off of a 2004+ owner looking to upgrade.

Edit: Here's a Gen III vs. Gen V vs. Whipple:

 

lol...no, they are very innefficient. the worst of all of the major boost options. they can definitely make those cars go fast... but being so innefficient imagine what a more efficient design would do? it would make those cars go even faster.

the centrifugal s/c's are peaky because they don't produce peak boost until redline, which is a reason why i won't use them. granted they're very efficient but because of that issue and parasitic losses (due to running it off of the crank) i'll stick with turbochargers.

 

They are ineffecient by comparison, yes, but they are cheap and I'd still much rather have one over being NA or spending oogles of money on a centrifugal setup or a turbo setup. This isn't entirely about budget, though, I like it for the powerband as well.

 

for the street they wouldn't be all that bad but when racing the powerband thing holds nothing to the other options... unless you shift well before redline a lot.

they would be pretty fun for the street but i'll still stick with my low cost turbo setup.

 

Ok, that's your difference in preference. I would like a more streetable power that I could actually use on a regular basis. Just because it doesn't keep increasing power as the powerband goes into the higher RPMs (read: 5500+) doesn't make it a useless option.

Besides...low-cost and turbo on a 4th gen are not to be used in the same sentence, so that's not really an option.

 

Remember the TB needs to be before the SC. That was Craig Mack's problem.

Their main advantages vs. turbo are their smooth low end based powerband, no lag, and ease of bolting on just work against you instead of for you. Our torquey NA VQ is already hard to get traction so I can't imagine with the additional torque that it would really be terribly useful. I don't doubt that it would be a good setup, but whether it would be worth the effort over a nice turbo or Vortech kit is subjective though.

 

That and the MAF.
If it can be done for cheaper than a full Vortech kit or turbo setup, it will be worth it just for that. The uber-torquey 3800's seem to make use of it pretty well, and I think we possibly could as well. Our advantage is better top end over them, though, so given stock-for-stock with the same M90 we should have a much better, much more useful powerband.

If I were to go this route, I wouldn't be looking for insane numbers. Comparable numbers to the Vortech units, maybe. The idea here is a fun, streetable setup. Nothing more, nothing less. Atleast in my case...I'm not sure what JClaw's goals would be.

 

The VQ35 already makes 100 HP more than what the 3800 does N/A, and my car weights 2750 lbs in street trim vs 3500 for 3.8-equiped cars, so they being "inefficient" is kind of moot when the difference between this and a Turbo setup is breaking them loose in 3rd vs breaking loose in 4th.

How fast do you want to go? My feeling is much faster than you'd ever want in a FWD car if you believe that their relative ineffectiveness is a ceiling to your 1/4 mile goals vs a Turbo Setup. There are 3.8's deep into 11's that still use the M90.

Dyno numbers mean little to me, and peaking at 5500 doesn't bother me either. I'd keep the stock 6550 rev limiter anyway for safety reasons. I don't agree with you about the powerhand though, all the dynos I've seen seem to support the idea that their peak numbers are low for how much area under the curve is available.

That said, your insight is much appreciated but I'm not looking to put down 500whp. I'd be happy with 350.

I tend to follow through.

 

are the cooled internally with oil? Gear oil or something inside the supercharger?

 

If it were most anyone else posting this I would just glaze over this thread as another idea from some joker who won't end up doing it, but because JClaw gets projects done when he starts something, I think it is promising. I also think it is a good idea for someone who has the knowledge and means to get it done. For your average "bolt on an SC" type guy though, this is not a good project.


One thing though about the dyno numbers vs track times. A GTP putting down 350whp would have more like 430-450tq, so that explains a little more thoroughly their trap speed vs hp conundrum. A vortech SC max with 350whp is looking at about 280tq, so comparing the track times of a 350whp vortech maxima and a 350whp GTP is ridiculous, the GTP has like 60% more torque while only weighing 16% more.

 

Precisely why, even though I did that little bit of research I posted about earlier, I wasn't going to post my ideas about this until I had the resources to do more than just "talk about it."
Very good points

 

I'm most likely going to collect the parts throughout March (We'll have Ice and snow here for another month or so so I won't be able to work on the car till late March anyway). I would start now, but FI is new to me and I want to do more research instead of just taking a dive into this.

I just saw an M112 on Ebay but... naaah.

 

Good, good M112? Don't even think about taking that step up


Also, to whoever asked about lubrication for the M90 above, it has it's own internal system of oil. Hence why above I said "and I might need to change the supercharger's oil." Since that needs done periodically just like the oil in your engine, though not quite as frequent.

 

A buddy and myself used a SC off of a '95 and grafted a homemade system onto his 280zx. His throttle body is after the supercharger and he's had no problems with it. He's got a blowoff valve and the supercharger has a bypass for low engine loads. I've seen pics of miata sc setups with the throttle body after the blower as well.

 

Well with the way we're talking about mounting it, it's not possible to have the TB after it, and it's not really possible to have a BOV either as a result, nor would there be a need for it.

 

Can you have the TB after the blower? Yes

Would it be much simpler to have it before? Yes

Craig Mack tried to use bypass valves, and all kinds of things before his project was ended for him, but it never really ran quite right. Putting the TB before it not horribly difficult with cable and would be even easier if you were drive by wire.

 

If we were using the M90, where it would sit would allow for an almost-stock position for the TB. We probably would need to give up slack in the TB cable, if anything.

 

Not having to move the throttle body was the simplest. Is there a link to Craig's issues? I'd like to read about what the problems were and what he tried to do to correct them. Did the supercharge being used have an internal bypass? I would think that would necessary for the tb to be after the sc or you'd get all kinds of surging with boost build up.

 

http://forums.maxima.org/showthread.php?t=261230

 

Thanks for posting that thread (Too bad the pictures don't work).

It seems to me that Craig overcomplicated his design, that was his one big problem. The shaft, the BOV, TB location.

Americans like simplicity. Be it the 2003-2004 Cobra or the 97+ GTP's, they basically shove the blower right on top of the engine, no intake manifold, then the TB, MAF, filter, that's it. I'm still curious on how the intercooler is included in the setup and where it goes in the route.

I've seen an impala with the IC literally between the engine and the blower, but I know the stock IC isn't there on either the GTP or the Cobra.

What I want to do is basically make something that is as close as possible to the stock GTP setup. It's proven and reliable. Truly insightful pictures are hard to find though.

 

I have his pictures saved on my computer, if you want them. I can't seem to find that thread about the Russian Maxima with a roots setup, though, and it's bugging me...

 

Anything that can help is appreciated.

 

Well then, in that case...

 

Thanks man.

I just read the last part of the thread and the link to the other one... what a sad ending Reminds me of when Neal's old car got totalled.

And...

 

Anytime. Yeah, sad ending indeed.

I think that for the $2500 he spent you could do a lot better than he did. With the simpler setups we have been talking about here, I'll bet it could be done for less. Especially considering he paid a whopping $500 just for the blower itself.

 

Does 400$ for an M112 sound good? Or a regular Gen III M90 for less.

- A good intercooler (so many for cheap on ebay, there has to be a good one buried under all that crap)
- Z32 MAF
- 555 injectors
- Bunch of 3" piping (I can get this from Vibrant in Canada, so not too expensive)
- 6 short velocity stacks (don't ask ) + some extra aluminum for the IM
- OBDI conversion for tuning (ECU + harness adaptor + dyno time + tuner's time = roughly 500$US once I've sold the stock ECU)
- SC pulley and belt (If I don't use my UDP instead, lol)

All labor by yours truly, except of course for the TIG welding (intake manifold and blower outlet), but I will still drill/fab/prep all the aluminum stuff myself.

I think it can be done for less than 2 grand, including the 'car specific' tuning.

Not much considering I was already planning on shelling out the 500$ for the tuning if I stayed N/A, and that I will save another 500$ by not buying a 10 bolt VLSD differencial and 4.47 ring/pinion that I would have done. So in the end maybe only 1 grand more than pursuing N/A.

I'm itching to start collecting the stuff now but I have not bought anything yet and until I do, it's still reversible. I'll give myself another week or two to mull this over.

 

Sounds good to me. Sounds about right, price-wise as well. Sticking with an M90 would make it a little cheaper. Also, not sure why you're rushing to get an intercooler. I mean, it's not necessary. Perhaps if I go this route in the future I'll just go with an M90 and forgo the IC.

Since you'll inevitably get to it before me, care to have a second outlet/manifold adapter made for me for a sum of $?

 

They don't call them 'Heaton' for nothing. Plus, knowing me, I can see myself getting an intercooler in the future, and knowing me, I can see myself replacing the M90 by an M112 in the future.

Dunno how that'd work out since I have a VQ35...