In my neverending quest to destroy another engine, Ive aquired an eaton M90 supercharger off a Bonneville. Preliminary fitting looks like with a little trimming to the right member of the decklid it should clear. Its gonna be close, but im hoping. I did mount the engine lower than stock, but if thats not enough, I have room to go down more. Ive got an extra engine now that I spun a rod, so im going to use that for my mockup. Looks like Im just gonna make a small box to bolt over the lower intake bewteen the fuel rails, then weld a bigger box to that for the SC to mount to. Im toying with the idea of welding the fuel rail right into the bax, dropping the SC another 3/4" I would just have it made so the injectors would plug right into the manifold. Im going to photoshop some stuff in a bit here

Heres my first idea, hopefuly you can make sense of it.
green is the heads, blue the fuel rail, red the lower section of intake, purlple middle, orange top. the lower would have bosses to bolt it to the stock LIM, then the middle would be welded to it, then the top might be welded if the hole is big enough to bolt the lower to the LIM, otherwise it would be removeable.

DARTH. Do you think you could do anything as far as reprogramming a 92 DOHC computer to work with the SC?

[This message has been edited by 86GT3.4DOHC (edited 04-15-2005).]

I'll be interested to see what you come up with.

I'm thinking about building my DOHC for a turbo or a supercharger.

Nolan

An M90 would be good for a kick in the pants, the 3.4dohc is capable of flowing a ton of air. Sounds like a cool project. I have a GN turbo I was thinking of putting on Sourmug's 3.4dohc.

[This message has been edited by crzyone (edited 04-16-2005).]

And what are you going to do with the turbo?

Does anyone know if there is any coolant passages in the SC? Normaly Id expect coolant to run through the trottle body, but I cannot see where there are any coolant passages in the SC. How do I know? well lets just say I have a black ring around my lips and im a little light headed. lol.

quote Originally posted by Sourmug: And what are you going to do with the turbo?

Well its a nice centerpiece for my dinner table, but if you want it I guess I can sell it

Needs a thrust bearing rebuild, I bought the turbo from Fast Indy Fiero. I've heard the rebuild parts cost around $75. Fire me a pm if interested.

edit to add some pictures

[This message has been edited by crzyone (edited 04-16-2005).]

these are the coolant passages on the M90:

the hole on the left is the EGR passage, on the right is the idle-sc-bypass-valve.

I think Its pretty appropriate to chime in right about now...

This is as low as I could get the blower and still have injectors fit underneith it.

86GT: were you thinking of doing anythinga bout a lower compression ratio or no?

I figure the compression will go down as the pistons crack . No, im not planning on using the full capacity of the SC, just helping a little. If nothing else, I have access to more engines.

As far as fittment. Ive got it plaaned out, so that the SC pulley sits about 2" higher than my idler pulley. It may not flow the best, but it should fit. My other idea is complely removing the LIM and just bolting a box to the heads, but then I'd have to make injector mounts, and have the injectors IN the LIM, so I'd have to make air tight plumming and wiring passtroughs in the side of the LIM

Hey there is a cheepo way to lower the compression, use camaro 3.4 pistons. I think they drop compression down to around 9.0:1 If you don't get too greedy with the boost I don't see any reason you shouldnt be ok. I still question how far down you will be able to get the blower, It doesnt like fitting between the heads. A thunderbird M90 SC would however fit alittle better, It doesn't have a large mounting flange pattern like the GM M90. Im really interested to see what you come up with.

I realize you guys have the M90's but what about using a vortech style supercharger similar to what Fierosound has done to his 3.4 pushrod?

http://www.fierosound.com/supercharger/supercharger.htm

Would there be room beside the 3.4 DOHC to fit one in?

Nolan

Edit cause I can't type on Saturdays

[This message has been edited by Sourmug (edited 04-16-2005).]

I like positive displacment pumps well, the real reason I chose an Eaton series blower, is for the brute low end, witch is what DOHC engines lack. I suppose you could use a centrifugal, but you would probably have to either give up A/C (look where I live) or you would have to jackshaft it off to the rear of the engine, even that is next to impossible, you can't get it past the heads.

LOL, look where I live! The AC just isn't that important, nice but not required. Assuming that the plumbing could be made to work if it is mounted in the AC compressor location I was thinking that it would be a good alternative so that nothing sticks up above the hood line.

Nolan

I dunno, but my SC snuggles right down inbetween the heads and I actualy have it resting on the fuel rail. I cut out the plate that will bolt to the LIM today. Of course it did not occur to me that I didnt have to cut out each individual port until after I had finished. Oh well. It'll make it stronger I guess.

quote Originally posted by Sourmug: Actually, I have a few questions though. I have read in a few other threads the suggestion to use the 3.4 Camaro pistons to drop the compression. 1. Why would they lower the compression? 2. The DOHC pistons have dished reliefs for the 4 valves wouldn't they be required in a replacement piston too? 3. What connecting rods should be used? OR Can the stock rods be shot peened to increase their stress resistance for moderate boost? 4. Can the 3.4 DOHC be bored and stroked for more displacement?

1. They are not as tall
2. Depends on how much you lower the compression, but generally, yes, they should have quad dishes.
3. Stock rods can be used, but with any hich horsepower build, should be upgraded. SBC 5.7" rods can be made to fit.
4. a .080 overbore is deemed "risky" by GM, and GM states that .060 is the maximum bore in the "safe" range, and will land you at 3.46L(3.5l)

It can be stroked, but no one makes a stroker crank, and the block may have to be machined for this. I am looking into it as we speak.

Honestly, I don't know why any of you are wasting your time on an M90. It is a terrible blower, and very undersized for the 3.4l DOHC. The only reason is cost, and if you are going this far into a 3.4, spend the money and do it right. The M112 would eb a much better choice, but still isn't a good blower. A Whipple 2300AX would work great, and a 3300AX if you have any headwork or overbore. This is just my opinion, an M90 is still going to add power, but you'd be better off modding it N/A, and it certainly be better on the motor.

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[This message has been edited by AaronZ34 (edited 04-16-2005).]

Yea, but I got this M90 for 150$ where as the whillples start at 10 times that, last one I saw was like 1600. As far as moding the engine, im open to any suggestions, no one makes cams, no one makes headers, no one makes intakes, the heads flow better than any other GM engine, and P&P gains would be minimal. About the only thing worth while would be bumping the compression, but thats not simple by any means, and requires dissasembly of the engine. The timing bump hurts low end. I cant see any worthwhile mod that would even come close to putting on a SC. Without a tubing bender, and a TIG, I cant make headers, I could make an intake, but why mess with all that when I can just make an adapter and bolt on a SC with a larger TB.

chrfab can do regrinds on the 3.4dohc. But, the stock cams should be fine for moderate boost. If you want to spend the $$ there are companies that will make you forged pistons for around $500. I believe the rods need to be small journal 327sbc and need to be machined down to fit on a 3.4dohc.

Its very possible to build a bullet proof bottom end for this motor. I had all my parts lined up to do it until I bought the N*. If you plan to make any decent power with boost, I suggest the forged pistons and sbc rods. The camaro pistons are hyper and not ideal comp ratio for the 3.4. I would get an 8.5:1 compression ratio. Don't forget ARP studs for the mains and rods.

I was planning on 450hp with a T61 turbo, and I had it figured out to only needing around 12-15psi with a T61. No intercooler, but would have had water/meth injection.

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Buy a fiero, become a mechanic

Hmmm. Heres an idea

Why not make a flat plate that would cover all the intake area on the SC, and leave a hole in the middle in the shape of the lim, then just make an extension to the lim to raise it above the fuel rail. If you look at the SC the output is reall only about 2" wide, but the whole sealed area is 4x4. as long as the output port was centered over the intake extension, it shouldnt hurt flow. but..

My main concern is, would it feed the #1 cyl more boost than the #6, since the output is shooting right at the #1 port? should I put some kind of baffles in there, or do you guys think it would be ok

Perhaps I wasn't clear. Do the 3.4 pushrod pistons have the reliefs for all four valves? If not, aren't they unusable for the 3.4 DOHC?

Nolan

No. and I don't know

quote Originally posted by Sourmug: Perhaps I wasn't clear. Do the 3.4 pushrod pistons have the reliefs for all four valves? If not, aren't they unusable for the 3.4 DOHC? Nolan

They might, a lot of pushrod pistons have 4 valve reliefs cuz they can be used on either side of the motor.

I still don't get your gripe with Eaton Blowers. They are the best roots style blower available, the most efficient and VERY affordable. I don't like Lysholm blowers that much because they have moderate parasitic loss (aka poorer gas mileage) and are VERY expensive. They rival the average turbo as far as efficiency, (power Vs air output) but the Eaton comes in not far behind, rivaling the lesser, efficient turbos.

quote Originally posted by Fierobsessed: I still don't get your gripe with Eaton Blowers. They are the best roots style blower available, the most efficient and VERY affordable. I don't like Lysholm blowers that much because they have moderate parasitic loss (aka poorer gas mileage) and are VERY expensive. They rival the average turbo as far as efficiency, (power Vs air output) but the Eaton comes in not far behind, rivaling the lesser, efficient turbos.

The Whipple 2300AX supercharger's hosepower draw is 13p less than the Eaton M90, both boosting the same 3.4l DOHC at 12psi, and it is 11hp less at 8psi. Sees to me it has better parasitic loss, so do your research. Secondly if its gas mileage you are worried about, we will talk about part throttle conditions. With the optional remote bypass valve installed, the WhippleCharger draws approximately 6hp, and makes about 1psi of boost on the 3.4l DOHC, while the Eaton draws 2hp, making no noticable boost. However becuz it is in boost range, and power benefits are higher, you will actually get better gas milage, animuL got 3mpg BETTER than with the Eaton at the same boost, becuz you don't have to press the pedal as hard. Lastly, you can't find a turbo that is even enar the M90 in efficiencies. Even stock turbos are over 50% Adiabatic efficiency on the right application. On a 3.4l DOHC on 8 and 12psi, the Eaton M90 is at 42% and 36% AE. Meanwhile, the 2300AX (the 3300 is even better, but not comparable to the M90), is at 66% and 64% AE. A GT35r turbo is at 78% AE at the same boost levels on the same motor. The Eaton DOES NOT rival turbos AT ALL, it barely rivals my air comrpessor.

Overall, not to be a dick, but do your research before you post, becuz I have, and once you do, I guarantee you will agree with everything I have said. The ONLY positive aspect of the M90 is price. Even intercooled using the best copper insert air to water intercooler available, its discharge temperature is still 15* higher than that of the 2300AX, and that is a lot.

One last thing, I don't even want to know how many --'s I got for that post...lol...But as I said, it is my opinion, the M90 is still going to add good power, and make the 3.4 a really fun car to drive, with great low end, wonderful middrange, and decent high end. So have fun, it is still a major mod to fit it, and I will respect you for that alone, also I cannot dog you all, cuz in the end, we are all together in the DOHC performance sector.

quote Originally posted by 86GT3.4DOHC: ...... No, im not planning on using the full capacity of the SC, just helping a little. If nothing else, I have access to more engines. ....

I guess this gives him permission to use the one he picked..........

I am sitting here reading the BROAD statements made about efficiencies and so on and those statements indicate to me that the people making them don't have that complete a knowledge after all about these topics. If you want to "help" people on these boards, be willing to declare the limits of your actual knowledge; otherwise someone might take such a statement as face value and spend $thousands on a project based on your 'quick reply'. !!!!!

It is pretty important to realize that superchargers "CAN" be (ie) 50% efficient, and turbochargers "CAN" be 75% efficient, etc etc etc - (numbers just for example here).
That doesn't mean they WILL give that performance on any given engine at any given rpm, much less the full range!!
Aaron, you are producing some very in-depth and complicated numbers; I have been digging into turbos and boost etc for a while now and I don't know where you would have gotten this info; is it avail thru a manufacturers website etc? could you pass it along? I would appreciate it and thanks! As always, it would help to show where they come from; graphs and charts etc; as the old "picture tells a thousand words".

I am going to try to post a pic that is in html format; not to hijack in any way but to show how a "78% efficient turbo" (as an example!) can be a 'bad' choice and a misnomer too.
Lets see if it will post then I can do a comparo with another.

This is a T58 and I plugged in values for the TDC at 2500rpm and up at 1000rpm increments. You have to pick values for volumetric efficiency and others including intercooler efficiency (and pressure drop) - which also includes the piping to/from etc etc etc. It is a SAMPLE.
See where the rpm selections lie; rising from left to right. Not a bad selection for a quickie....

Now THIS is a T68-1. Nice, big honkin' turbo. NOTE that it says it is 78% efficient!!! WOW; that is the one for me, right?
wrong. This would be a lousy selection (I left the other data the same; it is JUST a comparo) for the 3.4 in the scenario I made up.
So a turbo, OR a supercharger ISN"T such and such efficient, or even a good choice, just because of one number.
Just wanted to bring that point up, it has been posted so many times that turbos ARE 75% and S/C's ARE 55% or whatever.
That is a mistake to asssume that.
anyway
back to the show.

I was using the manufacturer's compressor maps for the Whipple 2.3l, 3.3l, and the Eaton units. I have them printed out here, with my handwriting ALL OVER them...lol

I did all of my research about a couple months ago when i wa splanning on supercharging my 3.4, not going n/a. I mapped probably 20 different units, including Kenne Bell blowers, Garrett turbos (GT35r is AWESOME), Whipples, Eatons, and then centrifugals. I compared every unit at 8psi, 12, and 18, all on a 3.4. Generally, for the Whipples, the efficiency ranges run in ovals, at a 45* angle. The boost lines then runs throug these, and you want your line to run right through the highest AE point. I'd replicate the info, but Eaton maps are a pain, cuz they aren't all in one graph, they use liek 6 graphs, so you have to plot it on eahc map, then combine the info, it takes forever.

I'd advise looking at this site, you can adapt the info easily for a 3.4l DOHC, http://members.cox.net/animul67/whippletechinfo.htm , this is where I started, and I learned so much. THis is where I first learned about all the compressor maps and such. Very helpful, and I adopted his views on Whipples. Most of that article is about a 2300 on a L67, but he gives the maps and explains how to use them.

I have no idea what the heck they mean, but they look kinda cool, lol. now stop hijacking my thread lol, j/k

quote Originally posted by 86GT3.4DOHC: I have no idea what the heck they mean, but they look kinda cool, lol. now stop hijacking my thread lol, j/k

HAHAHAHA!!!

Sorry to go off topic, you know, talking about superchargers on the 3.4l DOHC...lol

Yea but im the star of the thread, all you guys are just supposed to encourage me, tell me how cool I am, and tell me what a good job im doing lol

quote Originally posted by 86GT3.4DOHC: Yea but im the star of the thread, all you guys are just supposed to encourage me, tell me how cool I am, and tell me what a good job im doing lol

Dude, before I say anything else, let me just say that you are one of the coolest people I know, and that it looks AWESOME. So keep going, doing great so far!

AWWWWyou're just saying that :$

I want to see pics so I'm going to call bullshit on you even building a blown 3.4 until you give me AT LEAST 5 pics of everything. And when I say AT LEAST 5, I mean that 15 is more than welcome!

quote Originally posted by 86GT3.4DOHC: Well I got the lower plate completed. All the ports and bolt holes cut. I also made one of the long side pieces. Ive run into a problem, where the fuel rail rounds on the front of the engine, and the fuel return/fp regulator on the other. Im going to stop the plenum area just on the outside of the #1 runner on the front, and I made the back into a wedge shape to get around these problems. Ive been practicing my welding skills, but im still a little leary of 16 guage. I might just tack it up and pay to have it welded.

yup; looking forward to pix; can you gas weld? It is pretty easy to get the hang of it and it is GREAT for doing thin wall stuff!
I'm still leary of thin wall mig welding too; you gotta know when to 'move on' so to speak and yet hope you got enough penetration to hold things together. THEN you have the 'shape' issues (curves and rounds etc) to deal with; - yeah, it would be tricky.
Make sure you're set up and comfortable, then close your eyes, and away you go!!
oh, you have a helmet!?!?!
Keep it up; good topic and will be VERY interesting to find out what happens! What kind of boost are you planning/expecting? about 6 lbs?
gp

quote Originally posted by fiero308: yup; looking forward to pix; can you gas weld? It is pretty easy to get the hang of it and it is GREAT for doing thin wall stuff! I'm still leary of thin wall mig welding too; you gotta know when to 'move on' so to speak and yet hope you got enough penetration to hold things together. THEN you have the 'shape' issues (curves and rounds etc) to deal with; - yeah, it would be tricky. Make sure you're set up and comfortable, then close your eyes, and away you go!! oh, you have a helmet!?!?! Keep it up; good topic and will be VERY interesting to find out what happens! What kind of boost are you planning/expecting? about 6 lbs? gp

my MIG works great for down to 24guage steel - i'm still working on getting the hang of aluminum