jr69187

ok guys I got the car up and running. Everything is good gonna get an lsd rear end under it in the next few days. But it time to start the planning. I have an eaton setting here starring at me saying BOOST. So it is time to ask the question do i try and make a blowthru setup or do i do it the easy way and go suck thru. Please list the pros and cons of going each way. And give any recomendations i just got my job back and working so i have some money to poor into the little rex.

dan
85 gs
12a street port 1026 miles
rb header
straight pipe exhuast
79 air to oil cooler
and one of those boomin stereos.

Directfreak

iTrader: (2)

Blow through - definately, and use an intercooler. Otherwise after two runs, you will have so much heat soak that you will hate it.

Sterling

...Besides, I don't think the Eatons were designed for suck-thru (to be all soaked in gas, I mean.)
What size do you have?

PaulFitzwarryne

Blow through is the best option. Suck through gives problems with the impact of the fuel/air mix and it is difficult to add an intercooler.

jr69187

on the eaton subject i stole one off a wrecked gn ok. Well it is time for the great mines to come up with a good game plan to get this done now that i have money comming in i start to pick up the nessecary parts. Please list any and all possible parts for the install of an eaton m90 on a 12a.

thanks dan

Barwick

blow through..

I don't even know if you can use an intercooler with a suck through.

How much harder can a blow through be than a suck through? Physically I mean.. the carb setup could be odd, but you'll need to do something to it ANYHOW if you're going with boost, might as well replace it and get a better flowing one, and able to handle fuel delivery into boost.

I've also heard suck through can cause puddling of fuel in places you don't want them puddling at, even when the engine is running.

Just, blow through is the way to go.

Sterling

jr69187-
You had been away for some time months ago maybe? I do'nt recall seeing you on the board for a stretch, and during that time, I was asking all kinds of questions about my Eaton set-up.
Just do some searches.

The hardest part is going to be fabbing everything...Carb box, ductwork, and blower plenum.
You have alot of that ahead of you. Time to make buddies with a machine shop worker unless you have the tools yourself!

peejay

It's draw-through, not suck-through!

Blow-through has many advantages, but draw-through is not without its advantages as well. You need a much larger carb, but there's no need for any kind of blow off valve.

Sterling, I don't think an Eaton would have any problems with gasoline, after all they get plenty of gasoline that gets backwashed from the injectors. Even though the injectors are down in the ports on OW applications, that fuel just gets EVERYWHERE. If you don't believe me, next time you're in the junkyard look at all the carbon grunge on the backside of the throttle plate on a car with port FI... that carbon's got to be coming from somewhere!

jr69187

sterling thanks the state sent me on vacation for 4 months. Now i am back and getting the seven up and running at speed. put a new motor street port in it. racing beat header and open exhuast. and bunch fo other add ons now it is time to make the sc bolt on. So i will search and look at what all you found out.

peejay one of my friends runs a suck through on a 3.8 v6 and it runs like a top and was real easy so i was just wondering

dan

peejay

DRAW THROUGH!

jeremy

iTrader: (1)

ok guys, lets keep your sexual fantasies out of the discussion.

Sterling

Uh-Oh! Wajja do?

And peejay,
It's suck-thru, man. S-U-C-K Thru!
(& SCs make constant boost, too. )

REVHED

I wonder if he had Bubba as his cellmate.

jr69187

revhed comments like that tend to get writting untils stuck in your neck.

sterling lets try and keep to the subject. my state vacation is party of my life that is behind me.

So any ideas on what all i need to start gathering to piece this monster together.

dan

REVHED

Ok, my comment was probably a bit out of line.

But, I've just gotta know... what the ****'s a "writting untils"?

Sterling

Well O.K., No problem, man. It's bad mannors to even ask about such things - unless, of course, the subject is brought up by the person himself.
...And you did bring it up yourself, right?

"sterling thanks the state sent me on vacation for 4 months."

Well....
You need a real plan of attack, first. This is what I do:
I just drive my car as is, and play with the carburetor tuning when I have an urge to tinker. In the mean time, I've drawn detailed blueprints for the custom manifold I'm going to make, the blower plenum, and ductwork. I scrounge for parts and materials. I need aluminum...Lotz n' lotz o' aluminum!
Big blocks are hard to come by, and get pricey. I did manage to find one nice chunker that I'll be able to mill down for a few parts, but looks like I'll have to order a big one from MSC (machine shop tools & material distributer) for the plenum, as well as ordering a big thick sheet fdor the base.

Truth is, jr - and please don't take this the wrong way, but if you gotta ask that question, then you're not done drawing pictures yet!!!

Here, mull this over for a day...
Things that have to be fabricated, but fit together beautifully...

-Blower Plenum with inlet and outlet.
(Also need to concider linkage to make use of that bypass valve which will be of great use to you on long trips.)
-Blower's gotta be mounted to the engine.
(Since it's a blow-thru design I'm choosing, I'm going to mount an aluminum plate on top of the engine using the old rats nest mounting holes. The plate will cover the top of the intake manifold, and (obviously) have four holes in it where they need to be. The carb will be mounted on the manifold with this plate in between. Dig?
Now you've got a "floor" on wich to start building a sealed box. This plate will be the bottom of my blower plenum and the bottom of my carb box, will be shimmed with milled chunks of aluminum to ensure it is exactly perpindicular with the E-shaft pully and level with the carb, and secured very stoutly to the engine.
-I'm removing all extranious **** from my blower with my flex-shaft.
(Optional, but I think it'll make everything else a bit easier. I had to cut some of the rear section off the M-62 just to have it fit legnthwise, for example.)
-Figure out fitting for an intercooler. The bestest thing you can possibly do, is have the absolute best cooling system for the charge. Go look at cheap production car junkyard intercoolers.
An IC from a big production car is a hi-performance one for our cars!
-You have to think about your pulley configuration, ratio, and you'll need to design a bracket that will also use an idler pulley that is adjustable.
I'm taking the fact that many have mentioned possible E-shaft flexing due to pulley stress into concideration when designing my set-up. I will try to put equal load on both sides of the pulley, perhaps. I know some engineers. Time to consult them.

I will certainly post my findings, and any other little tid-bits.
But I'll tell you this; I'm a silversmith and a tool inventer (for that trade) and tool maker; I have a milling machine, a couple lathes, lots of metal working tools, a great machinest for a friend, and I still find this project to be intimidating!

It is one of those gambles- three fold, as I see it...
It could either cost you very little compared to say a Camden kit, Or wind up costing way more!
It could end up not working, blowing up your engine, or working beautifully!
It could take a really long time to complete it all.

I have the above mentioned luxeries, including an extra Rx-7 on which to build it so when it's complete and tested, I can just install it on my daily driver.

I'm not trying to disuade you, but I do wonder if you know what yer in for!

Directfreak

iTrader: (2)

well said.

ddsmith

Any of you guys seen the Gale Banks setup on a 350. I know it's a boinger but you can see some design ideas that probably should be incorporated in any good setup. He used a blow through design and one thing he had in the carb/air box was a dump valve that would open when vacuum hit a set value coming up. This dumped air to the engine compartment at idle but keeped the turbos spooled up. When the throttle was punched the vacuum dropped and the valve slammed shut. This setup pretty much does away with the lag normally experienced when the turbo slows down at idle. I'll see if I can attach a picture of the setup. It's on the cover of turbochargers book.

ddsmith

Sorry that last one didn't work. Try this one.

Directfreak

iTrader: (2)

You need more than just more air to keep the turbos spooled. You need fuel, and heat (explosions).

This has been covered before , and it was decided that it woluld not work on a street application, unless you liked rebuilding your turbos every week, like the Rally race car teams do.

Read through the Anti-Lag thread for yourself.

jr69187

Sterling very well understood. I have done supercharger on other cars before. mainly 3.8 buick regal and a thunder bird. Both are great runners the thunder bird was almost all bolt on. The buick had a bit of fabbing. Now over the past few days i have aquired a few more parts. Two full inter cooler setups one of a thunder bird sc and another off a iroc something i think a charger. But i got almost all of them and both of the sc on the motor along with everything attached. The reason i asked a bout blow or suck is because i did the regal on a suck system worked great i did the thunder bird on a factory set up. AS for metal shops there a quite a few around here and i have a friend that works at almost every one so parts fabbing is easy what i have to do is come up with the basic design and let them do all the parts construction. Right now my dad is trying to grasp everything about a rotary and figure out wich way to go. I like the suck through set up. but there are very few charger that will handle fuel running constantly in them. I know camdens do. And i ahve heard with the right mods you can do it to an eaton still researching that. My sc base is changing almost daily. I have about 3 good eatons and one dissasembled dad wanted to look at one so he tok it apart. So it is our model. The pulley setup i was pondering that what i had sugested was to put two rollers where the ac and smog went to spread the pressure more adequotly over the base pulley. This is still in discussion but this may be an idea for you. But the belt will get rather lengthy. i understand this is a lot of trial and error but i have a running 12 that i got for 100 bucks it is not strong but good enough to test on. I understand charger i just want to know which way is recommend for a seven. And the list deal is due to i want to double check mine and make sure i have it all listed and that there is nothing missing r if i have an extras. sterling i would really like to help you out on yours. i have a bunch of good ideas along with a bunch of friends that also like toying with this idea.


rev head that was supposed to be untinsul or a pencil favored weapon of an inmate.

Sterling

Well it sounds like you have a good handle on your project, good advice (who can dispute Dad?!), and friends to help you with it.

I'm pretty much going it solo, here. I don't have any gearhead friends at all! My set-up will be slightly different than yours, but to say just how would be a bit premature.
Let's just say both you and I will be breaking new ground here in our set-ups!
This of course, is the reason you can't seem to find any info about which is the best for the rotary. It's because very few people do this!

jr69187

Sterling sorry for the primative first post i was trying just to make an easy statment and see what they have to say. And then everyone thought i ws an idiot. And as for dad he has a degree in mechanical and electrical engineering. So i tend to listen to him more often than not. If does nto know how something works he takes it apart and makes it work better. So are you going to make the peice form the carb to the charger out of a solid block? My idea is find a way to get an eaton so that it can be used to suck through. (just cause i am convinced this is the easier route) When this car gets done it will not be getting drove daily. I have found a nice 85 gsl with 102k miles runs great all the options and racing beat exhaust. And it is only 1200 no rust. So i think that will be the new daily driver. And thus my little white gs will be a part time cruiser. So i am not worried about any dissengaging option. This may sound stupid but for the past week it has been blowing my mind in mad max and road warrior what is he doing to dissengauge the charger completly. Mean he pulls a lever and the belt stops spinning. How does he do that?? it has to be fake. Any way here is a quick run down on my purposed setup. Machin a plate to adapt down form an eaton to the intake. Make a new belt pattern with my proposed roller pulleys to make a more centered design on the pulleys. now is the hard parti have one eaton with an intake on the top which is wierd. But i hope to use it. Machine an adapter to the carb from the charger. Now this seems a like rather simple basic design. So i think it should work with very few problems. See anything wrong with the basic design this far. I am trying to plan this design some what off the buick we did. But for some odd reason i think i have forgot a big peice. Thank you and please give me any info

dan

Sterling

My plenum will be made from a giant cube of aluminum, yes. But when I'm done milling it out, it will resemble a giant three inch slice of square aluminum tubing. Kind of like a collar. But it'll have two chambers inside. It'll bolt to the bottom of the blower, and to the plate that is bolted to the engine. (Bolts go into the plate from the bottom, through the collar, and threaded into the blower. Then the plate gets bolted to the top of the engine.)
There will be an outlet for the boosted air, and an inlet at the other chamber for incoming air. There will be another piece bolted to the back of the blower and the collar to seal the inlet.

Really I have to draw it out and send you some pics.

You'll be able to get away with less fabbing using the blower with the inlet on the top in a draw thru configuration, but I really do think that the fab work might be worth do the blow thru. I don't know what the coefficient of expansion per degree for air is, but I do know from discussions here that 6 psi of really cold air (Intercooled) is gonna yield more power than ten psi of hot (uncooled) air. Unfortunately, a cold air box does'nt apply to draw thru blowers! The heat is a direct result of squishing the air. Obviously a cold air induction will help, but I have a feeling (I don't know for certain, but why would people use ICs if it were'nt so?!) it's gonna be very minor help at best.

It's a race, then, old man! A challenge, if you will! (Of purely friendly sorts...) If I get to the point of making my plenum before you have decided which route to go, I will mail to you my blue prints and a live template for you to do the same set-up. (If you want.) But this offer I make with no pressure to myself, and no gaurantee to you.
(I know...Not really much of an offer! )

Just do the research before you choose draw thru. Hate to see you do all that work only to know in the end that you could've gotten another 30 HP with 20% more effort.

jr69187

sterling my mind is pretty much made up i am going the opposite way of you but here is the kicker. If i get mine done and don't like than i will be glad to follow your tracks. as for cooling the air i have some plans. Me and my dad are thinking of taking the intake apart and taping it but i think that the water has to flow through the intake but who knows i might end up makeing my addapter a few inches taller. Then make it hollow with the basic u design meaning looping the water around the inside of it and running it on an inter cooler. But this will be known hopefully this weekend. I have got to go do some discussing with a rotoy head and see whta ideas he has. Listen to this there is a guy in spring field with a second gen but this is amazing he has made everything form scratch he running a big eaton like a 92 i think with a suck through but the car is on alchol and it is inter cooled. i am gonna set down saturday and talk with him i think what he says maybe very help full it took him tow years of trail and error before he got it right. So what ever i learn i will spread on also i will take the digi and get tons of picks evern thought it is a 13b it could be very help full. well we know have a friendly race. by race i mean to see who has more of drive cause really this is only a race of patients. I have a feeling i am gonna be doing alot of trail and error and when i get mine done i to shall share my plans. i am gonna digi log this so when i am done i will put all the info on a cd with tons of pics and some vidoes. and truthfully i am not looking for a huge improvement but i am looking to for proof. that proof is that it can be done. with out shelling out a crap load of money for a kit just a crap load of time. well i am done rambling. here is another idea how about on the intake to the charger you lined it with fined lines running off a circulating suply of co2. I played paintball and i made a can cooler like this it can freeze a hot pop in less than 2 minutes. with almost no loss of gas but on a larger scale it might be a dying idea but back to the drawing board. Lets try and keep the news comming back and forth so we can keep focused. thanks i am now done rambling

dan