200 MPH leaf blower...
09-22-01, 01:49 PM
#26
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Update...
After an hour long leaf blower testing session at The Home Depot, we determined that none of the electric ones blow enough air, and they all need a lot of power. The new plan is to get a good turbo from the junkyard and convert it to be belt driven and hopefully put it where my power steering pump was.
Flame away....
Actually please don't, but I would appreciate comments on this new plan. Thanks.
Flame away....
Actually please don't, but I would appreciate comments on this new plan. Thanks.
09-22-01, 02:06 PM
#27
Might be easier to get a supercharger from a factory supercharged vehicle from the junkyard instead of converting a turbo to centrifugal S/C. Better find a much better flowing fuelpump and bigger injectors in that junkyard too.
A header/ presilencer would probably be cheaper (especially used) and will give you a tried and true performance gain! Mabye leave the pioneering to those w/ millions so it doesn't matter to them when an idea doesn't pan out. If you love to tinker and are good at it (and the header doesn't take long enough /isn't hard enough) get a good running engine like the one you have and in all your spare time get some rebuilding/porting literature and build up a killer engine. The reason these cost so much is all the labor involved putting it together; if you have lotsa time it is a perfect project! A headered/ ported rotory is lotsa power and takes well to supercharging if in the future you still have to.
A header/ presilencer would probably be cheaper (especially used) and will give you a tried and true performance gain! Mabye leave the pioneering to those w/ millions so it doesn't matter to them when an idea doesn't pan out. If you love to tinker and are good at it (and the header doesn't take long enough /isn't hard enough) get a good running engine like the one you have and in all your spare time get some rebuilding/porting literature and build up a killer engine. The reason these cost so much is all the labor involved putting it together; if you have lotsa time it is a perfect project! A headered/ ported rotory is lotsa power and takes well to supercharging if in the future you still have to.
Last edited by BLUE TII; 09-22-01 at 02:15 PM.
09-22-01, 02:28 PM
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Looking for a factory supercharger is the other idea. We found 3 good turbos, but have not come across any superchargers yet. I'm not looking for a monster power increase. I just want 4-5 PSI (stock N/A ECU and fuel system should be able to handle it) so that I can feel a little more power. One day I will build a monster engine, but for now I'm a college student and I just want a little more power. Thanks for the input.
09-22-01, 02:37 PM
#29
Oh by the way, I know how it is to have your leaf blower idea kicking around in the head. 10 or so years ago when I was in high school auto I had the idea that I could take an electric ducted fan unit from an R/C airplane (alot more boost than leaf blower-lifts a heavy *** R/C "jet" w/ lotsa batteries into the air), put in a killer cobalt electric motor and lots of Nicad batteries-since weight wouldn't be an issue as it is in an airplane. My brilliant and quirky auto teacher (who normally helped in my half baked plans) talked me out of it. It would cost alot, I would still have to address fuel concerns and how long would the batteries last (couple of minutes it turned out).
I ended up rebuilding a 2.0 NAPZ engine for my car and had lots of fun porting, match porting manifolds, polishing ports and comb. chamber, CC'ing combustion chambers, deshrouding the valves, narrowing the valve guides, making adjustable cam timing sprocket (ran 27 deg. retard then tamed it to 18 deg.), shaving the head and block to raise compression ratio, lightening the flywheel alot advancing the spark timing alot and making sure everything was up to spec. The engine started out rated at 100hp and must have had ALOT more when I was done since it would redline in 5th gear (150-160mph) in my very unaerodynamic 1980 200sx! It was plenty of power for me and cost me only the cost of the gaskets.
So i know where you are comming from and had lots of fun doing things the conventional way and rotories will benifit from a performance rebuild way more than a boinger. My (very long) two cents
I ended up rebuilding a 2.0 NAPZ engine for my car and had lots of fun porting, match porting manifolds, polishing ports and comb. chamber, CC'ing combustion chambers, deshrouding the valves, narrowing the valve guides, making adjustable cam timing sprocket (ran 27 deg. retard then tamed it to 18 deg.), shaving the head and block to raise compression ratio, lightening the flywheel alot advancing the spark timing alot and making sure everything was up to spec. The engine started out rated at 100hp and must have had ALOT more when I was done since it would redline in 5th gear (150-160mph) in my very unaerodynamic 1980 200sx! It was plenty of power for me and cost me only the cost of the gaskets.
So i know where you are comming from and had lots of fun doing things the conventional way and rotories will benifit from a performance rebuild way more than a boinger. My (very long) two cents
09-22-01, 04:38 PM
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Great posts Blue TII! Sounds like you have a lot of experience tinkering with cars and the like.
Now as for the idea of belt driving a turbo I don't see how that will work either. Do you know that the compressor spins at incredibly high speeds to produce boost (something like 100,000 rpm or more)? There is no way that I know of to get that kind of RPM with a belt on a turbo. Plus how did you plan to attach a belt to a turbo? Everything is sealed inside the housings and opening the them up would result in a leak. The other thing to understand is that producing boost with a turbo is a result of good thermodynamics. Pressure differences on the front and rear of the turbine are what drives the turbo. These pressure differences are in large part determined by having an extremely hot exhaust that enters the turbo and is rapidly cooled after leaving the turbo. If I recall correctly this is why a larger sized exhaust allows your turbo to make more boost. The larger exhaust pipe creates a lower pressure zone that actually helps exhaust flow. If you take two engines that both flow the same amount of exhaust the one that produces the hotter exhaust will be better suited to turbocharging. Everyone knows that rotary engines are basically blowtorches and produce heat in excess of an equally sized piston engine. It is this heat and a strong exhaust pulse that allows us to use big turbo's that would normally be used on large piston engines. For example, I am looking at going with a T04B 60-1, P-trim, 0.81 a/r turbo. I was talking with a guy who has one of these turbo's on his high performance corvette engine and he claims it is too big for our little 1.3 litre. But everyone knows that this is not true. This turbo is a really good match for a rotary. However, you won't see too many Honda's going with this size of turbo because they just don't have a hot enough or strong enough exhaust to drive it.
The great thing about turbo's is that they are driven by a waste product of an engine. The downside is there is a delay between when you step on the gas and the creation of enough exhaust to spool your turbo. The bigger the turbo the longer it will take to spool. A supercharger on the other hand is driven by the crankshaft (I guess on a rotary that would be the eccentric shaft) and the response to throttle input is almost instantaneous. The downside is that the supercharger does require some engine power to be driven. Plus it is not as easy to adjust boost levels. On a turbo you just get a boost controller to increase your boost. On a supercharger you have to change your pullys.
One last thing is you are dreaming if you think the N/A CPU can handle 5 psi of boost. Did you know that is not much lower than the stock boost on an 87 T2? I can garauntee there is a big difference between both the fuel map and ignition timing map of a T2 and a N/A RX7. If I recall correctly there is something like 1 degree of engine retard for every pound of boost. Just slapping more fuel in will not be enough. Another concern would be the rotors themselves. In general a turbo car has a lower compression ratio. I don't know how a higher compression N/A rotor would handle the extra boost. Another thing I would worry about is the housing strength. I may be wrong but I believe that turbo housings are stronger with better cooling to handle the excess heat. Does the N/A have good enough oil cooling as well?
What it all comes down to is that if you want turbo power your best bet - money and time wise - would be to sell the N/A and get a T2. You will spend way more money turning your N/A into a turbo car than it would cost to upgrade. Plus with the T2 you get all the other goodies like 4 piston brakes, a LSD and I believe a stronger transmission.
If you want more power from your N/A listen to Blue TII and go the porting/header route. You will not get the same gains as a turbo gives on a T2 but it is the best you can do with an N/A. Another option is NOS for short bursts of acceleration. Other than that I would say save up for the T2. In the long run your wallet and your butt dyno will thank you for it.
Now as for the idea of belt driving a turbo I don't see how that will work either. Do you know that the compressor spins at incredibly high speeds to produce boost (something like 100,000 rpm or more)? There is no way that I know of to get that kind of RPM with a belt on a turbo. Plus how did you plan to attach a belt to a turbo? Everything is sealed inside the housings and opening the them up would result in a leak. The other thing to understand is that producing boost with a turbo is a result of good thermodynamics. Pressure differences on the front and rear of the turbine are what drives the turbo. These pressure differences are in large part determined by having an extremely hot exhaust that enters the turbo and is rapidly cooled after leaving the turbo. If I recall correctly this is why a larger sized exhaust allows your turbo to make more boost. The larger exhaust pipe creates a lower pressure zone that actually helps exhaust flow. If you take two engines that both flow the same amount of exhaust the one that produces the hotter exhaust will be better suited to turbocharging. Everyone knows that rotary engines are basically blowtorches and produce heat in excess of an equally sized piston engine. It is this heat and a strong exhaust pulse that allows us to use big turbo's that would normally be used on large piston engines. For example, I am looking at going with a T04B 60-1, P-trim, 0.81 a/r turbo. I was talking with a guy who has one of these turbo's on his high performance corvette engine and he claims it is too big for our little 1.3 litre. But everyone knows that this is not true. This turbo is a really good match for a rotary. However, you won't see too many Honda's going with this size of turbo because they just don't have a hot enough or strong enough exhaust to drive it.
The great thing about turbo's is that they are driven by a waste product of an engine. The downside is there is a delay between when you step on the gas and the creation of enough exhaust to spool your turbo. The bigger the turbo the longer it will take to spool. A supercharger on the other hand is driven by the crankshaft (I guess on a rotary that would be the eccentric shaft) and the response to throttle input is almost instantaneous. The downside is that the supercharger does require some engine power to be driven. Plus it is not as easy to adjust boost levels. On a turbo you just get a boost controller to increase your boost. On a supercharger you have to change your pullys.
One last thing is you are dreaming if you think the N/A CPU can handle 5 psi of boost. Did you know that is not much lower than the stock boost on an 87 T2? I can garauntee there is a big difference between both the fuel map and ignition timing map of a T2 and a N/A RX7. If I recall correctly there is something like 1 degree of engine retard for every pound of boost. Just slapping more fuel in will not be enough. Another concern would be the rotors themselves. In general a turbo car has a lower compression ratio. I don't know how a higher compression N/A rotor would handle the extra boost. Another thing I would worry about is the housing strength. I may be wrong but I believe that turbo housings are stronger with better cooling to handle the excess heat. Does the N/A have good enough oil cooling as well?
What it all comes down to is that if you want turbo power your best bet - money and time wise - would be to sell the N/A and get a T2. You will spend way more money turning your N/A into a turbo car than it would cost to upgrade. Plus with the T2 you get all the other goodies like 4 piston brakes, a LSD and I believe a stronger transmission.
If you want more power from your N/A listen to Blue TII and go the porting/header route. You will not get the same gains as a turbo gives on a T2 but it is the best you can do with an N/A. Another option is NOS for short bursts of acceleration. Other than that I would say save up for the T2. In the long run your wallet and your butt dyno will thank you for it.
Last edited by SoloRacer; 09-22-01 at 04:40 PM.
09-22-01, 04:52 PM
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One other thing I forgot to mention is consider putting your car on a diet. Did you ever notice how much slower your car feels when you have a 200 lb passenger with you? Power to weight ratio is directly related to your acceleration. If you can't get more power you can always cut the weight that needs to be moved. I know guys who race in an RX7 spec class here with 1st gen RX7's that are stripped of an interior and running street ported N/A 13B engines. Believe it or not they will give a stock T2 a good run for it's money. Weight reduction will also improve how your car handles. Things like heavy stereo gear, bigger wheels (thus heavier wheels which require more power to turn), carpet underlay, spare tires, etc. can be removed if extra performance is your goal. Just something else to consider.
Last edited by SoloRacer; 09-22-01 at 04:56 PM.
09-22-01, 05:22 PM
#32
Yeah, solo racer is right on.
You say you don't need a bunch of power, 4-5 lbs boost. A stock '87 TII is like 6 lbs and only makes 180hp. Your engine won't have as big of intake ports, though the comp. ratio increase may may up for the power; but at the expense of reliability.
Now, a headered full dual exhaust for an '86 na will give you about 170-190hp alone, no turbo lag (actually drastically improved bottom end) and will increase reliability over stock as you will have less heat, backpressure and no chance of clogged cats.
A ITS na race RX makes 200hp at the wheels-over 230hp at the flywheel. I believe this class doesn't allow porting. Hell if you would risk a NA at 5lbs boost and stock computer fuel system you would love the reliability of a bridgeport (50k miles?) and you could build one up to 200-300 hp flywheel. Look to old school rotory performance for lots of na power.
You say you don't need a bunch of power, 4-5 lbs boost. A stock '87 TII is like 6 lbs and only makes 180hp. Your engine won't have as big of intake ports, though the comp. ratio increase may may up for the power; but at the expense of reliability.
Now, a headered full dual exhaust for an '86 na will give you about 170-190hp alone, no turbo lag (actually drastically improved bottom end) and will increase reliability over stock as you will have less heat, backpressure and no chance of clogged cats.
A ITS na race RX makes 200hp at the wheels-over 230hp at the flywheel. I believe this class doesn't allow porting. Hell if you would risk a NA at 5lbs boost and stock computer fuel system you would love the reliability of a bridgeport (50k miles?) and you could build one up to 200-300 hp flywheel. Look to old school rotory performance for lots of na power.
09-22-01, 05:57 PM
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Thanks for the backup Blue TII. There is a guy here who races a tube frame 1st gen RX7 with a bridge or peripheral ported 13B that is making 280 hp. It's a fast little car but probably a bit too wild for a street car. It hardly holds an idle and you have to rev the hell out of it all the time to get the power. It does scream though and the guy who owns it has been racing RX7's since the early 80's and knows his stuff.
09-22-01, 09:33 PM
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I already removed a lot of my interior and other things that weigh the car down. I have stock wheels. I spoke with a couple guys at the SCCA regional at Thunderhill today, and I guess I will just wait until I get an FD in November. Thanks for everyone's input.
Also, what's up with the turbo kit they had for the N/A?
Also, what's up with the turbo kit they had for the N/A?
09-26-01, 04:12 AM
#35
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I really think you guys should take a look at what he is *trying* to do and see if you can offer constructive criticism towrds that goal. Yea it may be silly and mullet style to throw a leaf blower in your car, but hey he lives in redneckville Chico
I really think the idea of a Direct Drive turbo to supercharger conversion would actually be a good idea for the low boost application that he is trying to accomplish.
Lets get some ideas on how to make this work instead of, why not port or why not add an exhuast, or why not take passengers out of the vehicle, I am sure he has thought of these being he is a College Kid now..
I really think the idea of a Direct Drive turbo to supercharger conversion would actually be a good idea for the low boost application that he is trying to accomplish.
Lets get some ideas on how to make this work instead of, why not port or why not add an exhuast, or why not take passengers out of the vehicle, I am sure he has thought of these being he is a College Kid now..
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