Jump to content
HybridZ

supercharging z31


Recommended Posts

When The hell did this become a turbocharger vs supercharger

 

Save you useless correcting and rambling and get the ******* point a supercharger on a z31

 

almost nobody has been attempting to help this guy

It became one when people made statements as fact WITHOUT backing them up, then proceded the argument to BACK those statments up. So it really is helping the guy so he knows what he is really dealing with and how much work would be involved with a Forced Inductions system. As stated before he's gonig to have to create a custom setup. But I must say I'm really glad you chimed in and helped the guy out yourself...

Link to comment
Share on other sites

  • Replies 65
  • Created
  • Last Reply

Top Posters In This Topic

Guest ZFury
turbo can make MORE boost which equals more power than what the SC can

10psi is 10psi in the intake wheather it is made by a TC or a SC. Just cause a TC can make a 100psi and a SC can only make 50psi doenst mean much seeing your car will prolly only be able to take 20psi.

Link to comment
Share on other sites

Guest ZFury
http://i3.tinypic.com/11awbw2.jpg

Out of curiosity' date=' what is supposed to bolt to the bottom of that roots style blower if not the lower intake manifold? Some other kind of plenum that funnels the air into that intake tube? [/quote']

Just like a turbo, it has an "in" and "exit" pipe. You can see where the trottle body was attached at the rear, and where the other pipe goes (it has 3.8 on it).

 

A BOV or waste gate was a given.

 

I have never known IC to get TC intake temps down to or below ambient temps with out an O2 or NOS spray set-up.

Link to comment
Share on other sites

You must know some people that aren't very good at designing turbo systems then. Everyone I know has very manageable intake temps on their intercooled turbo systems. I've looked a bit closer at that setup, and concede that I stand corrected. The 3.8 box does indeed bolt on like a plenum, and funnels air into the intake tube as a postulated....

 

I'm willing to admit I don't have too much experience with the boost characteristics of roots and screw type superchargers, but I was in a CRX that had a Jackson Racing roots-type blower on it and it had what they advertised as the 12lb pulley upgrade on it. On the autometer boost gauge it would never quite make more than 9psi, and it most definitely didn't come on all at once, but increased with engine rpm. It didn't impress me much...

 

As far as trying to help this guy with his original problem, without pictures of what he is working with, anything beyond the vague-ish advice he got at the beginning of the thread is going to be difficult to give.

Link to comment
Share on other sites

an O2 spray into your intake to cool it down??? why use a sc in the first place if you got o2 spray

 

zfury, i really like centrifugals, and i think its a decent, easy setup for some street applications because of its simplicity, but what has been stated it true, turbos are much better then superchargers

 

 

 

for example, you have a motor that will rev to 7000 rpm and 10 psi is the max it will handle without blowing up.

 

centrifugal: you will have boost right away but your setup will only be able to have 10 psi max (or itll blow up). you can set 10psi for 3000 rpm but when you go to 3500 rpm BOOM, so you set it up so it'll have the 10 psi at 7000 rpm. that means that it should have 5 psi at 3500psi (considering its perfectly linear). You will have a very nice lenear torque curve all throughout. next gear you'll be back at 5000 rpm and have to climb the boost ladder.

 

turbo:again, a turbo that will do 10psi (which wont be a very big turbo at all) at 2000 rpm you probably wont have any boost, and the motor may even be a little slower than N/A because of the extra backpressure. but at 3000 rpm itll start to rise and will probably be 5psi, and by 3500 itll become 8-10psi. and from then till redline it'll stay at 10 psi. next gear, at 5000 rpm you'll be at full boost and you'r flying

 

your right up to 3500 rpm in 1st gear you may make more power so say in 1/4 mile race the first 2 seconds you will be faster but soon after that the turbo will catch up

 

this is all not considering parasitic loss

 

I like centifugals because if you dont want an all around faster car, but instead a cheap, very simple setup that you could setup in one day, its the way to go.

 

If someone could post a dyno of similar motors with the same boost with a turbo and a sc. i member a mustang magazine where they did just that. turbo, cetrif, roots and screw. you could easily see the actual numbers and differences in how the power was delivered

Link to comment
Share on other sites

 

intake tube goes from air filet to in the side of the sc. the big square outlet is connected to the "3.8 sc" tube and goes to the intercooler. then it goes to TB and manifold. In the picture it looks like the backside of the sc is attached to the plenum which goes to the manifold but it isnt.correct me if I'm wrong, last time i seen a sc tbird was a while ago

 

when first seen this setup i was actually impressed with how they designed and plumbed everything together. these cars made i think like 225 hp or something which was equivelant to the 5.0 mustangs

Link to comment
Share on other sites

It became one when people made statements as fact WITHOUT backing them up, then proceded the argument to BACK those statments up. So it really is helping the guy so he knows what he is really dealing with and how much work would be involved with a Forced Inductions system. As stated before he's gonig to have to create a custom setup. But I must say I'm really glad you chimed in and helped the guy out yourself...

Well thanks i help when i can :)

 

Back on topic

 

Before you decide to supercharge it i would have it checked make sure theres nothing extremely bad

 

Also how many miles does this engine have on it might be time for a rebuild with the sc in mind

Link to comment
Share on other sites

When The hell did this become a turbocharger vs supercharger

 

Save you useless correcting and rambling and get the ******* point a supercharger on a z31

 

almost nobody has been attempting to help this guy

 

When it was mentioned a supercharger being put on a Z31. Nothing against doing it really... just that a better setup is readily available since the Z31 had a turbo version stock.

 

Basically what I'm getting at is that the time' date=' money, and work you'd have to put into getting the supercharger in would be much greater than doing a turbo setup that would end up being superior.

 

I have never known IC to get TC intake temps down to or below ambient temps with out an O2 or NOS spray set-up.

 

No one ever said anything about an aftercooler getting the intake temps below ambient since that's impossible without, as you said, some sort of spray or an air to water aftercooler.

 

an O2 spray into your intake to cool it down??? why use a sc in the first place if you got o2 spray

 

I believe he was talking about spraying onto an aftercooler core. It wouldn't be O2 but more likely CO2 or Nitrous. I've never heard of anyone spraying oxygen... not that it couldn't be done as it would still be quite cold. I'm not sure.

 

 

Oddly enough, centrifugal superchargers actually still have lag like a turbo. You don't get instant response like a roots or screws but some lag then low boost that has a linear increase to redline where it peaks boost.

Link to comment
Share on other sites

To digress a little bit more...

 

After WW2 the biggest, most powerful aircraft piston engine was the Wasp Major R4360. It had a build in supercharger that was fed by two 14" diameter turbochargers and developed 4,300 horsepower in its final form. Pratt and Whitney tried a number of times to eliminate the supercharger because it took 425 horsepower just to spin it at the takeoff power setting. They tried larger turbos, bigger intercoolers, turbos in series, etc. and even installed a small jet engine that was fed by the exhaust from the turbos (compounding). But, all those efforts failed becasue they could not make up the loss of the 1,900 additional horsepower the supercharger produced.

 

What's the point of this little tidbit of information? Concerns about parasitic losses are sometimes overblown.

Link to comment
Share on other sites

wow thats a lot of info ... a thought would the drag of a clutch fan and an a/c be equal to the drag created by the sc? im only running ps and alt. its a centifugal so i'm considering an intercooler. im not trying to make maximum boost, just make it more fun to drive. thanks again

Link to comment
Share on other sites

To digress a little bit more...

 

After WW2 the biggest' date=' most powerful aircraft piston engine was the Wasp Major R4360. It had a build in supercharger that was fed by two 14" diameter turbochargers and developed 4,300 horsepower in its final form. Pratt and Whitney tried a number of times to eliminate the supercharger because it took 425 horsepower just to spin it at the takeoff power setting. They tried larger turbos, bigger intercoolers, turbos in series, etc. and even installed a small jet engine that was fed by the exhaust from the turbos (compounding). But, all those efforts failed becasue they could not make up the loss of the 1,900 additional horsepower the supercharger produced.

 

What's the point of this little tidbit of information? Concerns about parasitic losses are sometimes overblown.[/quote']

 

I would hope that turbocharger technology of the 2000's would be better than turbocharger technology of the 1940's.... but... all of the info I can find on that engine states that it was supercharged and mentions nothing about turbo chargers.

 

Also, I can't find anything about the 4,300 hp except for on Wikipedia... which I wouldn't trust whatsoever. I did however find that some people were making over 4,000 hp in racing aircraft built in the 1980's.

 

http://www.hill.af.mil/museum/photos/wwii/r4360.htm

http://www.eagle.ca/~harry/aircraft/fury/reno.htm

 

Either way though... I'm not saying the parasitic drag makes the supercharger pointless. What I am trying to get everyone to understand is that the turbocharger is more EFFICIENT than superchargers. In engines, efficiency is everything.

 

Of course superchargers are going to make a lot of power. Turbochargers are just going to make the same power more efficiently and in being more efficient have the ability to make even more power.

 

If/when variable geometry turbine/vane turbos become common place, I wouldn't be surprised if superchargers will become a thing of the past (except for the collector type). Heck... the new Porsche 911 TT uses them and they spool so quick the 3.6 liter flat 6 is able to make 502 ft. lb. of torque at 1,950 rpm and holds that up to 5,000 rpm.

Link to comment
Share on other sites

http://www.pw.utc.com/about_history_classic_r4360.asp

 

http://www.geocities.com/Pentagon/Quarters/4980/engine9.html

 

The power ratings for the engine varied depending on altitude with the final production version of the Wasp Major R4360-45 hitting the "magic" 1 horsepower per cubic inch number. This engine was fitted to the B36J.

 

The turbochargers were normally governed to not allowed full boost (80 psi total) until the plane was over 10,000 feet. They also used variable vane and variable nozzle turbochargers, water and alcohol injection, and very large intercoolers (after coolers) variously cooled with air, water, and alcohol. Just because something turbocharger related appears new in the automotive world doesn't mean its actually a new idea or hasn't been tried before.

 

BTW... The supercharger was also overdriven by 637%.

Link to comment
Share on other sites

Anyways back to the z31. You need to get a compressor map for that sucker. It has one just like the turbos, it's the same style compressor. The intake gets plumbed the same way with bov. The drag and ***. load can be quite high, build the mounts solid. I guess I could try to run the numbers if you really wanted, but I would recomend that reading.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...