RX7Club.com - Mazda RX7 Forum

RX7Club.com - Mazda RX7 Forum (https://www.rx7club.com/)
-   2nd Generation Specific (1986-1992) (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/)
-   -   my n/a supercharging project complete (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/my-n-supercharging-project-complete-289791/)

DCRotor 04-06-04 02:07 PM

im gonna put the brackets i've drawn from the pictures zbrown put up as soon as i finish school here at howard. then im going to put them in AutoCad. If zbown can give me some measurements it will help out alot.

\mm/

-B-

scathcart 04-06-04 03:24 PM


Originally posted by Atticus
:p: Someone had to do it! :D
And it had to be a newb making comment to one of the most knowledgable forum members :rolleyes:

ANYONE who has spent anytime at the track will realise that NOS is an accepted name for all brands of Nitrous oxide. Its the same as Kleenux (a brand).... or do you always ask someone for a "lubricated facial tissue with menthol action" to blow you nose with?

Atticus 04-06-04 03:35 PM


Originally posted by scathcart
And it had to be a newb making comment to one of the most knowledgable forum members :rolleyes:

ANYONE who has spent anytime at the track will realise that NOS is an accepted name for all brands of Nitrous oxide. Its the same as Kleenux (a brand).... or do you always ask someone for a "lubricated facial tissue with menthol action" to blow you nose with?

Newb or not, In no way was I serious, hence the two different smilies. I didn't think that it would be taken seriously, since it's an image commonly tossed around this site with a humorous feel to it, and most everyone here knows RETed to be a knowledgable source.

But that's just my newb apology.

*EDIT* But anyways, lets hear about these pics of the bracket coming along.

zbrown 04-06-04 03:40 PM

:D

NZConvertible 04-06-04 03:58 PM


Originally posted by DEZERTE
i dont think anybody thinks they are getting turbo power by doing this...
Judging by some of the responses so far, I think many do.

...obviously you will need a larger exhaust if their going forced induction. I think he was referring to the manifold in not modifying the exhaust.
Well he said, "not having to modify the exhaust at all", which I thought was pretty clear. Either way, the manifold is part of the exhaust, and neither the stock manifold or a set of aftermarket "NA" headers are going to be ideal for a supercharged engine. If you want to do this properly, the whole exhaust needs to be upgraded, just like a turbo's.

patman 04-06-04 04:23 PM

Yo, I could make these brackets. $75 a pop, shipped. If i get enough interest, I will buy an M90 and design the bracket (or zbrown can send me specs and i'll cut him a percent). Would take me a month or so to get the first ones done. Anyone interested PM me.

pat

poor_red_neck 04-06-04 04:44 PM


Originally posted by NZConvertible
Judging by some of the responses so far, I think many do.
Well he said, "not having to modify the exhaust at all", which I thought was pretty clear. Either way, the manifold is part of the exhaust, and neither the stock manifold or a set of aftermarket "NA" headers are going to be ideal for a supercharged engine. If you want to do this properly, the whole exhaust needs to be upgraded, just like a turbo's.

Well, considering you aren't using a turbo.. what other kind of header can you use?

Right now I have a 2.5" exaust from the stock manifold back. Bonez high-flow cat, and POS magnaflow mufflers which I could care less if they get shot out.
Soon to get a RB "streetable" header.

I would assume this would work out for a little while for some mild boost. I am in no way shape or form considering this will give me turbo results, or the same power. I'm going for some cheap power. Sorry, I can't go for this other supercharger simply because its "more efficient." I'm on a budget here. It's easy to say on the internet "yeah, just get this supercharger instead." Yeah, no biggie... just 2K+ or something like that :rolleyes:

poor_red_neck 04-06-04 04:47 PM

I don't know if you are talking about upgrading exaust will improve efficiency... or for the sake of your car blowing up if you don't.

I could care less right now if its efficient. Now if I blow a hole through one of my mufflers, and it ignites the gas tank... that's a different story. Although I doubt this would happen.

poor_red_neck 04-06-04 04:57 PM

http://cgi.ebay.com/ebaymotors/ws/eB...category=33741

Hmm... says he has an intercooler to go with it. Did the thunderbirds come with a water to air intercooler or something?

SonicRaT 04-06-04 05:22 PM


Originally posted by poor_red_neck
http://cgi.ebay.com/ebaymotors/ws/eB...category=33741

Hmm... says he has an intercooler to go with it. Did the thunderbirds come with a water to air intercooler or something?

http://www.google.com

Please search, this is easily obtainable information, and it's just poluting the poor thread by posting 500 questions answered 6000x on google :)

On a more thread related note. He's using stock injectors, and he claims to not have heard pinging. What do the stock injectors support, 180hp max?

rotarygod 04-06-04 05:39 PM

Here's my rant about the debate here.

There are some people who will always hate superchargers no matter how much success someone else has with them. This also applies to some people in regards to nitrous and turbocharging. It is pointless arguing with these people.

Here are the facts about doing this.

If you want the most ultimate horsepower that you can get out of your engine, this isn't the way to go. There are so many people that argue on the grounds that one has more ultimate potential than the other. If the owner only wanted 30 hp more and got it for less than $300, how was that not worth it? That is a hypothetical number or course. Nothing else has that value. No hassle of refilling a bottle. No worry about plumbing new coolant and oil lines. It is still much more work to install even a simple turbo on the car.

If even a stock turbo needs a spacer to clear the n/a lower manifold, needs a downpipe made, needs oil and water lines, loses emissions (some of us have to worry about that), and loses the ability to control the 6 port system. How is that less or equal work to just making a bracket, making an idler pulley, changing a belt, and keeping the ability to use the emissions devices and retain the 6 port system? Both need simple airflow plumbing. I don't see the argument. It is less work no matter how you look at it. Does it have the same ultimate potential? Probably not but as long as the owner is happy, this is really an irrelavant point anyways.

Yes you can do this to a stock engine. Any engine will have more potential with better flowing intake and exhaust ports, even the stock T-II engine. No one is debating this. Whether you bolted on a turbo or a supercharger, a larger exhaust will still help power production. No miracles here.

Saying things such as a turbo has a more efficient compressor wheel than an Eaton supercharger is a very blanket statement. Some turbos will be more efficient and some will be less. Get specific before you compare. If people are going to flame others for sarcasm then they had better be more detailed with their so called facts. That was a true or false statement depending on the comparison.

When not under boost, the supercharger car is still going to have better fuel economy and more low end power than a turbo car. Notice I said when NOT under boost. A small turbo (such as the stock T-II unit) is hurting exhaust flow considerably even over the stock n/a exhaust manifold. This is going to hurt any exhaust tuning ability that may be beneficial to added power. Yes a turbo has parasitic loss too. Maybe not as much but it is there. A supercharger doesn't take as much power to spin as everyone thinks it does. If you were to take the belt completely off of the supercharger and start the car, it would still spin regardless of if the bypass valve is open or not. It does take a little power though but a small turbo choking off the exhaust flow does the same thing. As with anything there are exceptions to this but we aren't talking about big properly sized turbos and a few thousand dollars.

For a total of $300 he made an upgrade that is clearly the most bang for the buck. Nitrous is more expensive. Even if you were given the nitrous system, you still have to pay for the gas. This won't take long to hit $300. A stock turbo can be bought and installed. It is plausible that the total dollar amount could come out near $300 but it is still much more work. The whole point of this is how to get a nice power upgrade for little money, with as little work as possible. He got it.

It isn't enough power for some, it is fine for others. Any system can be improved upon. Yes he can do alot of other things to get more power out of it. He can add an intercooler, he can get a standalone ecu, he can port the engine, he can fab up a nice exhaust and intake, etc. Of course power would go up. This applies to bolting a turbo on too. All of that can't be done for cheap though. If you don't like superchargers you are just wasting your time arguing with the people who think it is a good idea. This thread wasn't started as a debate. It was started to show others what he did to HIS car. If people don't like his upgrade, don't do it. If you do like it, try it. Simple really.

I personally have a turbo and a ported engine and still wouldn't have done it any different if I were doing it all again. It doesn't mean that I can't appreciate the work of others, regardless of whether or not it beats mine. I wouldn't care if it did. Mine makes me happy and that is all that counts. Instead of turning this into an argument thread, lets just keep it on topic. If you like it ask questions. If you don't then that's fine too but don't argue with others about it. Start a new debate thread for that. We already have enough of them.

The Spyder 04-06-04 05:39 PM

Damn it you guys just drove up the price for SC of thunderbirds by %50!!!!

j/k :D

Na I actual had a SC, fun car, wrecked it though.... wounder if I should try this :D.

NZConvertible 04-06-04 06:24 PM


Originally posted by poor_red_neck
Well, considering you aren't using a turbo.. what other kind of header can you use?
I was referring to headers suitable for a NA engine, which will be different to a set of headers designed for a considerably more powerful supercharged engine.

[I don't know if you are talking about upgrading exaust will improve efficiency... or for the sake of your car blowing up if you don't.
It's not going to blow up; it's just not going to run as well as it should. Exhausts should be designed to suit the engine's power output, not whether it's turbo'd or supercharged. How many TII owners have trouble deciding between (for example) RB's NA or Turbo exhausts? ;)

Having said that, rotarygod has made some good points about the goals and costs of this project. However I don’t think there are many people here who would actually undertake a budget DIY supercharger install. Most seem content to wait and pay for a kit (if one ever eventuates).

DCRotor 04-06-04 06:51 PM

can someone put up the pic for me so i can show you waht ive done in autocad with the intake bracket.

DEZERTE 04-06-04 07:09 PM


Originally posted by NZConvertible
I was referring to headers suitable for a NA engine, which will be different to a set of headers designed for a considerably more powerful supercharged engine.
um, where would u find such a thing? why wouldn't RB headers work?

TwEaK 04-06-04 07:24 PM

DC ROTOR email me the pics luis_aps727@hotmail.com and ill put em up right now....
TwEaK

DCRotor 04-06-04 07:53 PM

tweak i sent you two. the picture shows the plate for the SC to the TB i need the hole size for the screws the it will be complete. I hav 3 test tomarrow ( Physics, Calculus3, Econ) so i wont be posting anymore tonite or working on the drawings you will have to wait till after wensday to see the others and some 3d stuff. untill then can anyone get me more measurements on anything (zbrown....i'd like to have the ones for the sc mount angles, lentghs, heights, etc.)
\mm/
-b-

RETed 04-06-04 07:58 PM


Originally posted by rotarygod
For a total of $300 he made an upgrade that is clearly the most bang for the buck. Nitrous is more expensive. Even if you were given the nitrous system, you still have to pay for the gas. This won't take long to hit $300. A stock turbo can be bought and installed. It is plausible that the total dollar amount could come out near $300 but it is still much more work. The whole point of this is how to get a nice power upgrade for little money, with as little work as possible. He got it.
Okay, and this is my beef with this thread...

Just because the original poster made everything for $300 doesn't mean you can too.

REPEAT.

You are talking about an eBay purchase.  I won't even go into a possible bad transaction that involves faulty or bad merchandise - if you haven't been through one, it's one of the most frustratings things in life.  This means prices will vary; unless someone can show me a site where you can buy these used SC's for a set guaranteed price, the initial purchase of the SC is variable.

The SC and pulley bracket system has to be made out of very strong or very thick materials.  Precision has to be done down to under 1/8" (for the pulley), or else it's going to eat belts like a mofo.  I would estimate a typical machine shop would charge anywhere from $100 to $300 for this work.  Unless you got the resources and can weld like the original poster (which I think most of you cannot do), you not going to get a "free" bracketing system.

Although the poster did not run into any problems with the stock fuel system, upgrading is is highly recommended.  The stock fuel injectors can barely support 200hp at the wheels; I think you will be getting very close to this power level.  The stock NA fuel pump can support slightly more (maybe up to 250hp), but it's always safer to upgrade to a Walbro which will give you way-more-than-enough capacity from the fuel pump...at about $100, it's no excuse.  This means upgrade fuel injectors and the upgrade fuel pump costs need to be factored in.  FC turbo fuel injectors are pretty cheap and easily available, and I've seen prices anywhere from $50 to $150 for a set of 4.

A boost-dependent FPR would be a good thing, and the easy path would be to to swap for a stock FC turbo FPR (or entire fuel rail).  Retrofit BDFPR's are still over $100+ for a brand new one.

Now, as for the SC sizing...  Running something off a 3.0 liter 6-cylinder piston motor is just about perfect.  When we size turbos, we use the equivalent 2.5 liter to 3.0 liter piston engine displacement figures for application to the 13B.  Good job!

NZConvertible is right about the exhaust.  Running a stock NA exhaust will choke performance.  Although not required, it is highly recommended to run a freer-flowing exhaust system.  You might be able to get away with the stock exhaust manifold, but a mid-pipe, high-flow cat / test pipe, and aftermarket cat-back should be installed.  This is even more money to throw at this project.

A fuel computer is highly recommended to fine tune the fuel delivery.  Even used units are over $100, but many are already running them on their NA's.  If you don't have one, you should budget for one.  Ignition timing you can fudge with moving the CAS; if you need to retard it a little, just dial te CAS back a few degrees.  A retard box, brand new, is serious money.

Do you think your stock NA clutch can handle the increased torque?  I highly doubt it.  A new or upgrade clutch may be able to hold, but if you're running a stock OEM clutch that has a lot of miles on it, you're going to be buying a new clutch, guaranteed.  That's another couple hundred for the clutch!

I can go into a whole bunch of other things that can give you trouble, but this is going to end up being an epic, so I'll stop here. :)

In the end, I tally the final cost to be MINIMUM about $1,000 for a "typical" install.

If you have a highly modified NA with upgrade clutch + AFC, it's still about $700 minimum.

If you're starting with a car that's bone stock and high mileage, we're talking prices approaching closer to $2,000!

Bottom line, there's a LOT of auxuliary things you need to budget for and getting a "$300" SC off of eBay is just the start of your upgrades.  Don't look foolish and thing you can get your car running reliably with just a $300 SC...


-Ted

DEZERTE 04-06-04 08:14 PM


Originally posted by RETed
Okay, and this is my beef with this thread...

Just because the original poster made everything for $300 doesn't mean you can too.

REPEAT.

You are talking about an eBay purchase...
etc etc everything that Ted said


-Ted

You are smart sir. Good post.

edmcguirk 04-06-04 08:38 PM

You can wire the secondaries open permanantly because they are supposed to close and prevent weak vacuum signal at lower RPM.

This supercharger is positive dispalcement and will force air through the open ports. The more the better.

Positive displacement superchargers tend to move the torque peak lower. The usual response is to tune the engine more to the upper RPM to compensate.

ed

edmcguirk 04-06-04 08:46 PM

I just want to doublecheck the calculations. The rotary engine pumps 1300cc or 750cc per revolution?

1300cc would place the max boost of the M95 at about 8 psi. That has to be the right one because 750cc would max out at 25 psi. (forgetting for the moment that the eaton SC is pushing it's limits at 15 psi)

ed

rx7vert1988 04-06-04 09:43 PM

sc question
 
is it the bigger the puller the more the boost or the smaller the pulley? i need to know, Im in the process of doing this, im not waiting for s/c mounting bracket info, ill figure it out!!!

alwayssideways 04-06-04 09:54 PM


Originally posted by edmcguirk
You can wire the secondaries open permanantly because they are supposed to close and prevent weak vacuum signal at lower RPM.

This supercharger is positive dispalcement and will force air through the open ports. The more the better.

Positive displacement superchargers tend to move the torque peak lower. The usual response is to tune the engine more to the upper RPM to compensate.

ed

i know on some car syou can remove the butterflies completly and that way you wont get lag.. and since your running a belt driven sc you should have no real issues with vauccum and what not

Chimeron 04-06-04 09:56 PM

It depends on the ratio not the simply the size of one pulley. Think about two wheels, both the same size, both are spinning at the same speed, now shrink so that it has half the circumference, now the small one is spinning 2 times for every once of the larger one.

White_FC 04-07-04 12:28 AM


Originally posted by RETed

Just because the original poster made everything for $300 doesn't mean you can too.

...

-Ted

Great point.. Just like my n/a turbo conversion cost about the same, because I could do all of it myself (bar some welding...) and I got lots of parts insanely cheap..

FWIW, here in Australia M90's seem to be going for about $800 2nd hand!!

From what i've seen anyway... Hardly a cheap option when 2nd hand turbos are about $200-300...

All about supply and demand though I guess.. :)


All times are GMT -5. The time now is 11:08 PM.


© 2024 MH Sub I, LLC dba Internet Brands