oddball thought s/c carbed TII?
11-12-04, 07:07 AM
#1
Respecognize!
Thread Starter
oddball thought s/c carbed TII?
i knwo racing beat makes the carbed intake manifolds for the TII motors. but rather than run the turbo still, could i mount like a Weigand 8-71 or 6-71 on top of the carb then alter the pulleys a bit to make it work with the 45 degreeish angle? That would be one mean motor....I could custom fabricate the pulleys if need and any oddball mountings. Plus the low end would be nice!!!
11-12-04, 07:20 AM
#2
wtf's a piston
Join Date: Mar 2004
Location: Englewood, FL
Posts: 1,717
Likes: 0
Received 0 Likes
on
0 Posts
why supercharge it? Supercharger is not the way to go, Nice blowthrough systems can be achieved with the knowledge and $$. This guy that my buddy bought his TII off of, he had a 87 with 380rwhp running consistant 11.8's. It was carburated, bigger turbo, intercooler,etc. but it can be done, just don't expect to get good gasmileage. If you want a nice book on carb'd turbo setup's look at "Maximun Boost" by Corky Bell, best $30 book I've ever read.
11-12-04, 07:38 AM
#4
Respecognize!
Thread Starter
oh, the other thing is, i dont understand how to connect the forced air from the turbo to the carb effectively. My guess is make a bracket special for it.
11-12-04, 08:04 AM
#5
i am legendary
Join Date: Sep 2003
Location: Kirkland, WA
Posts: 8,478
Likes: 0
Received 0 Likes
on
0 Posts
1. Why supercharge it when it's already turbo and set up for it?
2. Why carb it? Fuel injection will always be superior.
3. If you're going to supercharge a TII and ditch the turbo please stop, sell it, buy an N/A, and do it to that.
2. Why carb it? Fuel injection will always be superior.
3. If you're going to supercharge a TII and ditch the turbo please stop, sell it, buy an N/A, and do it to that.
11-12-04, 08:12 AM
#6
Respecognize!
Thread Starter
Originally Posted by dDuB
1. Why supercharge it when it's already turbo and set up for it?
2. Why carb it? Fuel injection will always be superior.
3. If you're going to supercharge a TII and ditch the turbo please stop, sell it, buy an N/A, and do it to that.
2. Why carb it? Fuel injection will always be superior.
3. If you're going to supercharge a TII and ditch the turbo please stop, sell it, buy an N/A, and do it to that.
2. i beg to differ for this case. Fuel injection is more tuneable and can be easier to do so, but the cost would be high. Also the carb can make much more power with any form of boost then a FI. FI is the bastard child of years of emissions laws.
3. TII has a different compression therefore making my life easier when i comes to preventing detontation. Because the ECU wont be there to control the fuel meaning i need all the help i can inorder to control the motor. I cant simplying run a boost controller. I mgiht be able to make it work, but it would be 4 kinds of bitchy.
if that still makes you question, well tough, ill do what i damn well plz.
Trending Topics
11-12-04, 08:32 AM
#8
i am legendary
Join Date: Sep 2003
Location: Kirkland, WA
Posts: 8,478
Likes: 0
Received 0 Likes
on
0 Posts
1. Heard of a ballbearing turbo? There's your low end if you care about it that much. And a turbo setup can be plenty reliable if you do things right. Reliability of any rx7 is dependent on the knowledge of the owner. Did I mention how much torque can be produced with the right tuning? If you're looking for torque, you're never going to gain a whole lot (comparibly) with an RX-7, that's just the fact.
2. You're wrong. FI is better and will always net the most power with the right tuning. Carb is just the easy way out. Carb will not make more power than FI with boost, period.
3. I more meant this because you're going to bastardize a TII and that shouldn't happen.
I know you'll do what you want, but it's a complete waste of time and money when you have a car already setup for boost, FI is superior, and your torque is never going to be what I'm guessing you want or expect.
2. You're wrong. FI is better and will always net the most power with the right tuning. Carb is just the easy way out. Carb will not make more power than FI with boost, period.
3. I more meant this because you're going to bastardize a TII and that shouldn't happen.
I know you'll do what you want, but it's a complete waste of time and money when you have a car already setup for boost, FI is superior, and your torque is never going to be what I'm guessing you want or expect.
11-12-04, 08:35 AM
#10
Originally Posted by 2ndGenV8RX-7
2. i beg to differ for this case. Fuel injection is more tuneable and can be easier to do so, but the cost would be high. Also the carb can make much more power with any form of boost then a FI. FI is the bastard child of years of emissions laws.
Not true at all!
A new carb will cost you a good chunk of $$$, plus modifying it for the "blow thru", that puts you in the $600-$700 range, that is VERY close to stand alone price. I heard that the last batch of E6K were going for less than $1000!
11-12-04, 08:44 AM
#12
Originally Posted by 2ndGenV8RX-7
i would like to hear from someone who has done a carbed TII instead of speculation.
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/neiltiis-rx7-pics-159009/
11-12-04, 10:17 AM
#13
Locust of the apocalypse
Join Date: Apr 2003
Location: Directly above the center of the earth (York, PA)
Posts: 2,553
Likes: 0
Received 1 Like
on
1 Post
Originally Posted by 2ndGenV8RX-7
i can get a used demon carb 4 barrell for free. 
here we go again... no wonder the 3rd gen guys look down their noses at us... everything on this forum seems to be about being a cheap ***.
Ever wonder why there are so few 2nd gens out there that are in really good shape..... cause broke *** guys want to hop up their cars and don't have the goddam common sense to save the cash up and do it the right way the first time.
I'm not really singling you out man... I just get SOOO tired of watching guys destroy their cars by try to cut every corner and get power to the ground the cheapest way they can possibly ferret out.
You go ahead and get that demon car and get a blow though adapter and a new fuel pump and pressure regulator (you can't use the injection stuff, it'll blow the bowls right out of that carb if you hit it with 40 PSI of fuel pressure) and go on with your bad self. It will work. I just think its like putting a rubber band powered engine from a balsa model airplane on a B2 stealth... a Regression in technology.
Take it from a guy who came from the Muscle Car sceene, my first car was a 66 fairlane with a 390 and a blower...... Tuning forced induction motors is an order of magnitude easier with fuel injection that it is with a carb... there are so goddam many parts that can effect the performance of the carb, a zillion jet combinations, floats, throttle pumps, venturis.. yeesh... You gotta tear the intake apart and f' with the carb every time you want to make a change to the fuel set-up or dial in more boost...
Injection is an order of magnitude easier... you slap a wideband on it and program the injectors to puke out this much fuel at this much pressure at this RPM to get the A/F you are looking for and blammo, you be rockin...
Even if you go with a carb, you are still going to need access to a wideband to make sure you have the carb set up right so you don't blow the motor.
Id NEVER go back to a carb setup.. ESPECIALLY when my car is already set up for injection (fuel rails, injection points, ect.)
Running a good injection system is going to cost more and you'd be hard pressed to have someone just GIVE you one for free, but technology costs money, carbs are outdated technology soon to get buried under layers of mud and become fossils for future gear heads to did up and put in museums.
I have a bunch of Holly carbs laying around too, but I decided to wait, squirrel away the money for the Haltech and the Rebuild and to it all at once. It took several years to get the money together.. but i'm glad i waited.
11-12-04, 10:28 AM
#14
Locust of the apocalypse
Join Date: Apr 2003
Location: Directly above the center of the earth (York, PA)
Posts: 2,553
Likes: 0
Received 1 Like
on
1 Post
Originally Posted by dDuB
1. Why supercharge it when it's already turbo and set up for it?
2. Why carb it? Fuel injection will always be superior.
3. If you're going to supercharge a TII and ditch the turbo please stop, sell it, buy an N/A, and do it to that.
2. Why carb it? Fuel injection will always be superior.
3. If you're going to supercharge a TII and ditch the turbo please stop, sell it, buy an N/A, and do it to that.
Also, not EVERY car is a good candidate for a turbo.... Our Cars are... BUT, because of the exhaust port design of the RX-8... a turbo system is simply not as efficient as it is on the 7. Which is why you can read about the Mazda Supercharged "Project RX-8" in a few of the mags on the newstand right now and rumours are flying about a supercharged, 2-seat rx-7 set for 2006 production.
2. I agree totally.
3. pros and cons here... boost is boost... supercharging an N/A has the same problems as Turbo'n an N/A... the higher compression limits the amount of boost you can push in. Therefore, if the exhaust pressure out of a 13b wasn't so high, i'd say it might be viable to di a supercharger...
11-12-04, 11:33 AM
#15
i am legendary
Join Date: Sep 2003
Location: Kirkland, WA
Posts: 8,478
Likes: 0
Received 0 Likes
on
0 Posts
^^^
Yah for 3 I was more refering to the fact that if he wants to do a supercharger so bad than don't bastardize a TII with it, do it to an N/A.
And yes N/A's can't handle as MUCH boost, but higher comp + lower boost will still = same power. Like 12 psi on high comp would be ~18 on low comp TII rotors, it's all relative.
Yah for 3 I was more refering to the fact that if he wants to do a supercharger so bad than don't bastardize a TII with it, do it to an N/A.
And yes N/A's can't handle as MUCH boost, but higher comp + lower boost will still = same power. Like 12 psi on high comp would be ~18 on low comp TII rotors, it's all relative.
11-12-04, 01:23 PM
#18
Eat, sleep, work, mod.
Join Date: Jun 2001
Location: Long Island
Posts: 2,517
Likes: 0
Received 0 Likes
on
0 Posts
I've seen one locally...don't think he's a forum member. Carb'd, bridgeported and supercharged S4...as I recall, I was told it would spin the tires if given WOT while cruising in 4th on the highway!
11-12-04, 01:38 PM
#19
Rotary Freak
Put the supercharger on top of the carbeurator? For one that won't fit under the hood and for another thing I'm not even sure that would work. Air goes into the carb, gets compressed by the supercharger, and then goes into the engine. You'd have to fab a custom intake manifold for the Weiand, then you'd have to find a way to get it to fit under the hood.
Also, I'm not sure of what type of compressor the Weiands are, but if they're basic roots-type superchargers, then you're not going to be able to run enough boost to make the lower compression ratio beneficial. I'm talking maybe 9 lbs. non-intercooled, maximum. On top of that you'd get about 15mpg.
Also, I'm not sure of what type of compressor the Weiands are, but if they're basic roots-type superchargers, then you're not going to be able to run enough boost to make the lower compression ratio beneficial. I'm talking maybe 9 lbs. non-intercooled, maximum. On top of that you'd get about 15mpg.
11-12-04, 02:09 PM
#20
Respecognize!
Thread Starter
Originally Posted by snub disphenoid
Put the supercharger on top of the carbeurator? For one that won't fit under the hood and for another thing I'm not even sure that would work. Air goes into the carb, gets compressed by the supercharger, and then goes into the engine. You'd have to fab a custom intake manifold for the Weiand, then you'd have to find a way to get it to fit under the hood.
Also, I'm not sure of what type of compressor the Weiands are, but if they're basic roots-type superchargers, then you're not going to be able to run enough boost to make the lower compression ratio beneficial. I'm talking maybe 9 lbs. non-intercooled, maximum. On top of that you'd get about 15mpg.
Also, I'm not sure of what type of compressor the Weiands are, but if they're basic roots-type superchargers, then you're not going to be able to run enough boost to make the lower compression ratio beneficial. I'm talking maybe 9 lbs. non-intercooled, maximum. On top of that you'd get about 15mpg.
wrong^^^^^^^^^^
11-12-04, 03:07 PM
#21
Rotary Freak
Originally Posted by 2ndGenV8RX-7
wrong^^^^^^^^^^
11-12-04, 03:51 PM
#22
Mountain Rotary Mod
Join Date: Nov 2003
Location: Freaking Poland!!
Posts: 2,411
Likes: 0
Received 0 Likes
on
0 Posts
The tradional setup is to put the carb on top fo the SC. The reason is compression.
A roots style SC does not compress the air internally but actually uses the manifold for compression.
If you put the SC a head of the carb then you risk damaging the SC when the throttle plates slam shut. The SC is still turn X amount of air that's just going to be forced nowhere. You'll get a boost spike the moment you open the throttle up and then you get a nice PING noise from the rotors.
A roots style SC does not compress the air internally but actually uses the manifold for compression.
If you put the SC a head of the carb then you risk damaging the SC when the throttle plates slam shut. The SC is still turn X amount of air that's just going to be forced nowhere. You'll get a boost spike the moment you open the throttle up and then you get a nice PING noise from the rotors.
11-12-04, 04:47 PM
#23
kill it with BOOMSTICK!
Originally Posted by dDuB
2. Why carb it? Fuel injection will always be superior.
An EFI system will always, and I do mean always be superior for any engine that varies its speed (rpm) on a regular basis BETWEEN THE LOW TO MID RANGE.
A carbeurated system will ALWAYS be superior to an EFI system on an engine that runs in the mid to high range of the RPM spectrum on an engine.
The reason carbs act like this is that they allow more atomization AT HIGH RATES OF AIR FLOW. EFI systems don't allow for atomization in the proper, more to the fact that they A. spray the fuel at the hot intake valve (not our case, dur!) causing it to vaporize instantly or B. spray at an atomization plate that forces the fuel to be picked up by the air speeding by.
This being said, the optimum setup would be the EFI system that we have currently with a single or pair of injectors in the intake pipe that come online at ~5500-6k rpm, thereby giving you the best of both worlds.
11-12-04, 04:54 PM
#24
Mountain Rotary Mod
Join Date: Nov 2003
Location: Freaking Poland!!
Posts: 2,411
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Falcoms
I always like it when conversations like this pop up. Time for the *proven* facts:
An EFI system will always, and I do mean always be superior for any engine that varies its speed (rpm) on a regular basis BETWEEN THE LOW TO MID RANGE.
A carbeurated system will ALWAYS be superior to an EFI system on an engine that runs in the mid to high range of the RPM spectrum on an engine.
The reason carbs act like this is that they allow more atomization AT HIGH RATES OF AIR FLOW. EFI systems don't allow for atomization in the proper, more to the fact that they A. spray the fuel at the hot intake valve (not our case, dur!) causing it to vaporize instantly or B. spray at an atomization plate that forces the fuel to be picked up by the air speeding by.
This being said, the optimum setup would be the EFI system that we have currently with a single or pair of injectors in the intake pipe that come online at ~5500-6k rpm, thereby giving you the best of both worlds.
An EFI system will always, and I do mean always be superior for any engine that varies its speed (rpm) on a regular basis BETWEEN THE LOW TO MID RANGE.
A carbeurated system will ALWAYS be superior to an EFI system on an engine that runs in the mid to high range of the RPM spectrum on an engine.
The reason carbs act like this is that they allow more atomization AT HIGH RATES OF AIR FLOW. EFI systems don't allow for atomization in the proper, more to the fact that they A. spray the fuel at the hot intake valve (not our case, dur!) causing it to vaporize instantly or B. spray at an atomization plate that forces the fuel to be picked up by the air speeding by.
This being said, the optimum setup would be the EFI system that we have currently with a single or pair of injectors in the intake pipe that come online at ~5500-6k rpm, thereby giving you the best of both worlds.
11-15-04, 06:43 AM
#25
Respecognize!
Thread Starter
for the purpose of this project i am going to experiment with a N/A block for me being cheap reasons in case it blows the first time. But i think ill go with my supercharger plan. not an eaton though. Lysholm! As for the carb, i am going to combo the FI AND the carb together. There was another thread floating around about this and the combo worked well. seeing it will be just for power, nothing can dump more fuel then a carb and the injectors will help the low end.
and the person who posted something about the supercharger being after the carb, read a book!
and the person who posted something about the supercharger being after the carb, read a book!