Removing exhaust port sleeve pro's please help
08-06-05, 04:29 PM
#1
Senior Member
Thread Starter
Removing exhaust port sleeve pro's please help
Hey guys, I'm bridgeporting my motor and I want to remove the exhaust port sleeve, and port it basically as big as I can. I can easily remove the sleeve, my question is whether or not thats a good idea. I was afraid there would be too much heat onto the aluminum housing. But perhaps with the port SO much bigger it isn't an issue. So I just wanted to see if anyone has done this. Thanks for the time, Evan
08-18-05, 05:35 AM
#7
Senior Member
Originally Posted by Zero R
If you dont put something back in there you will loose velocity for sure. No, there have been no heat related issues that I have come across yet.
ive always wonder if ther are any gains from doing this or if i was just kidding my self.
ive removed them before on na and turbo but didnt really have a gd chance to compare against anything. i did notice more undrivable but wasnt sure if this was from my large bridge ports. or poor jetting. but seem to perform well from 3-8000rpm even in na form. so not sure?
I have left them in my most recent engine but have not completed project.
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08-18-05, 10:26 AM
#8
BDC Motorsports
Given the size and volume of the exhaust port, it would seem to me to be more advantageous to retain that volume by using an exhaust sleeve similar in shape and size throughout instead o f just removing the sleeve all together ....
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08-18-05, 01:50 PM
#9
Originally Posted by BDC
Given the size and volume of the exhaust port, it would seem to me to be more advantageous to retain that volume by using an exhaust sleeve similar in shape and size throughout instead o f just removing the sleeve all together ....
B
B
These are actually ported larger than is possible with the stock sleeves installed but the area stays constant all the way out. It uses a 1 7/8" primary. Velocity is most important. Volume always comes second.
Last edited by rotarygod; 08-18-05 at 01:52 PM.
08-19-05, 03:19 AM
#10
Originally Posted by rotarygod
You mean like mine?
These are actually ported larger than is possible with the stock sleeves installed but the area stays constant all the way out. It uses a 1 7/8" primary. Velocity is most important. Volume always comes second.
These are actually ported larger than is possible with the stock sleeves installed but the area stays constant all the way out. It uses a 1 7/8" primary. Velocity is most important. Volume always comes second.
Did you ever post any results on this set-up RG?
08-19-05, 09:22 PM
#11
I never ended up dynoing them. I have used them in several different configurations now on a few different engines over the past several years. They make a very nice improvement in how the car drives. I don't really care for dynos near as much as all the people out there that require proof before believing something. Dyno's only tell full throttle power and I care about the power the most where I am 99% of the time which is almost at every other load. Dynos don't show this. They are very nice and really help the low to midrange. Drivability is improved. They aren't expensive to get made and aren't difficult to have made either. I have been planning to get some new sets made but never got around to it. The nice thing about the way I did them is that they are now held in by set screws. I tapped the holes where the pins used to be. If I want to take them out, all I need is an allen wrench.
The guy who had the most use of these sleeves with forced induction hasn't been into rotaries now for a few years. I heavn't talked to him in at least that long. When he first installed them, he found that he had to use a turbo exhaust side that was MUCH larger than what he had with the conventional sleeves and he still had quicker spool. He got much higher power as a result of the larger exhaust side being less of a restriction. He loved the drivability but commented that sometimes he thought it came on boost too fast. He always was one for very peaky power too so decide for yourself what he meant.
A problem he did find was that with some of the turbos he used, the added heat would actually melt the turbine blades. The original turbo he had when he was using the stock sleeves melted since it was sized for the stck sleeves. Alot of people remember this and just assume that thios technique will automatically melt their turbos. Not true. You need to size them properly first of all. Most of the new turbos now have Inconel blades. If you have these, you will be fine and you will get the benefit from the sleeves. If I recall correctly he was using a large streetport with these sleeves. I don't recall the turbo model but he had 2 different combinations that he was playing with when he got out of rotaries. ONe was with a P trim exhaust clipped 20 degrees. No idea what the a/r was. The other he played with was a Q-trim and a 1.32(?) a/r. That's very large. He apparently had no trouble spooling these up. There is alot of energy in those ports. Unfortunately he didn't do any more experimenting with them so what exactly works best is still a mystery.
I have used them on non turbo cars and have had very nice results. low and mid range have increased. A downside to the higher velocity is that with more energy in the exhaust it is harder to muffle. The housing in the picture is from an engine that I briefly had running with forced induction. It ran wonderfully naturally aspirated though. That car is now in rotary heaven though so the motor is back out waiting to go back into a new home. My other car has a standard exhaust sleeve and is streetported. It is a GSL-SE and the exhaust sleeves are not interchangable between the older and newer 13B engines. I had a set lying around but couldn't even use them. Since I was short on time, I didn't get a chance to get new sleeves made for it. I just put the engine back together. The next engine for it will definietly have them though.
There were a couple of other people in Houston several years ago that had the sleeves installed and had decent results. They weren't on the forum and I thinnk their cars are long gone. For right now there aren't any currently running sets out there. Everyone has gotten out of these cars and I just haven't had a chance to get them back in my current car. There is someone else on the forum who is doing the same principle. He takes out the stock sleeves, fills the area in with weld and then makes them basically the same out of the engine. He loves his. I first got the idea from Paul Yaw.
The guy who had the most use of these sleeves with forced induction hasn't been into rotaries now for a few years. I heavn't talked to him in at least that long. When he first installed them, he found that he had to use a turbo exhaust side that was MUCH larger than what he had with the conventional sleeves and he still had quicker spool. He got much higher power as a result of the larger exhaust side being less of a restriction. He loved the drivability but commented that sometimes he thought it came on boost too fast. He always was one for very peaky power too so decide for yourself what he meant.
A problem he did find was that with some of the turbos he used, the added heat would actually melt the turbine blades. The original turbo he had when he was using the stock sleeves melted since it was sized for the stck sleeves. Alot of people remember this and just assume that thios technique will automatically melt their turbos. Not true. You need to size them properly first of all. Most of the new turbos now have Inconel blades. If you have these, you will be fine and you will get the benefit from the sleeves. If I recall correctly he was using a large streetport with these sleeves. I don't recall the turbo model but he had 2 different combinations that he was playing with when he got out of rotaries. ONe was with a P trim exhaust clipped 20 degrees. No idea what the a/r was. The other he played with was a Q-trim and a 1.32(?) a/r. That's very large. He apparently had no trouble spooling these up. There is alot of energy in those ports. Unfortunately he didn't do any more experimenting with them so what exactly works best is still a mystery.
I have used them on non turbo cars and have had very nice results. low and mid range have increased. A downside to the higher velocity is that with more energy in the exhaust it is harder to muffle. The housing in the picture is from an engine that I briefly had running with forced induction. It ran wonderfully naturally aspirated though. That car is now in rotary heaven though so the motor is back out waiting to go back into a new home. My other car has a standard exhaust sleeve and is streetported. It is a GSL-SE and the exhaust sleeves are not interchangable between the older and newer 13B engines. I had a set lying around but couldn't even use them. Since I was short on time, I didn't get a chance to get new sleeves made for it. I just put the engine back together. The next engine for it will definietly have them though.
There were a couple of other people in Houston several years ago that had the sleeves installed and had decent results. They weren't on the forum and I thinnk their cars are long gone. For right now there aren't any currently running sets out there. Everyone has gotten out of these cars and I just haven't had a chance to get them back in my current car. There is someone else on the forum who is doing the same principle. He takes out the stock sleeves, fills the area in with weld and then makes them basically the same out of the engine. He loves his. I first got the idea from Paul Yaw.
08-19-05, 11:18 PM
#12
Originally Posted by rotarygod
I first got the idea from Paul Yaw.
Thx for the reply. I was thinking about experimenting by custom making an exhaust manifold that actually protrudes into the removed exhaust sleeve. Do you think that could work? I think it would.
08-20-05, 10:07 PM
#15
t-von, What you are thinking of will work to a point, I've been thinking about this same thing. Its actually motivated me to get the flowbench out and make sure everything is working and start playing. (Had to order some oil from Dwyer) Sleeves would be easier to make and test but those darn rules won't let me use them. Oh well, the rules just make it that much more fun when you do find some extra power the other guy hasn't.
Thats the great thing about a flowbench, no guessing what works. You can't tell by looking at it!
Thats the great thing about a flowbench, no guessing what works. You can't tell by looking at it!
08-21-05, 10:49 PM
#16
I've got a flowbench too. Paul inspired me to build it. That's the beauty of these sleeves. The first tests I did with them were on a stock sized exhaust port. The only change were the sleeves. Still the same port timing. On the flowbench I saw a nearly 30% increase in flow and this was through a 1 5/8" exhaust pipe! This means velocity increased which is also very beneficial to tuning. No one can say that this didn't help as the flow increased. That's most people's whole goal behind porting. I don't need a dyno to tell me that's going to be beneficial. My goal with a bench is to first and foremost get the most flow I can out of the same sized hole. Sadly alot of people don't understand this. On your flowbench, do you test to see where the dead flow spots are? I use a welding rod with different sized ball bearings on the end of each one. Then I move them around in the flow to see what effect it had. If there was no change, I add clay to that area on the bench and retest. If everything stays the same or flow goes up, I also know that velocity went up. You probably already know this though.
If you are under race rules you probabaly won't be able to use these. You probably can't even use the tubing insert into the stock sleeve to give you the same effect. Typically rules prohibit anything protruding in past the flange or gasket.
If you are under race rules you probabaly won't be able to use these. You probably can't even use the tubing insert into the stock sleeve to give you the same effect. Typically rules prohibit anything protruding in past the flange or gasket.
08-22-05, 09:24 AM
#18
T-von, do a yahoo or whatever search for "flowbench" and start reading. There are quite a few sites out there with homebuilt flowbenches. I built my first one, crude but it worked, and the Superflow 110 I have now was actually given to me! My friend said, "you take it, the manual is written for someone who already knows how to use it" I will probably build a bigger one sometime, MORE POWER!! This will be the first I have used one on anything rotory (I used to run those OTHER engines.... they have things called valves and stuff 
rotorygod, same techniques, velocity rules! Have you read the info from the DART heads co. on 'wetflow'? Interesting stuff, makes you rethink some things, but its hard to argue with the increase in performance a flowbench can help you find.
And about the rules, You scared me for a minute, I had to go back and re-re-reread the rules again. The intake manifold can't protrude into the port but there is nothing about the exhaust! It least until THEY find out what we are doing...
rotorygod, same techniques, velocity rules! Have you read the info from the DART heads co. on 'wetflow'? Interesting stuff, makes you rethink some things, but its hard to argue with the increase in performance a flowbench can help you find.
And about the rules, You scared me for a minute, I had to go back and re-re-reread the rules again. The intake manifold can't protrude into the port but there is nothing about the exhaust! It least until THEY find out what we are doing...
08-22-05, 04:05 PM
#19
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i always thought about this
one thing bugs me:
do you "convert" the oval shape of the exhaust port to a circle and just watch for equal cross-section so that a normal exhaust manifolds with tubular runners can be used?
that would compromise velocity somewhat, but it would be way easier to build a matching manifold.
one thing bugs me:
do you "convert" the oval shape of the exhaust port to a circle and just watch for equal cross-section so that a normal exhaust manifolds with tubular runners can be used?
that would compromise velocity somewhat, but it would be way easier to build a matching manifold.
08-22-05, 04:48 PM
#20
Originally Posted by jgrewe
rotorygod, same techniques, velocity rules! Have you read the info from the DART heads co. on 'wetflow'? Interesting stuff, makes you rethink some things, but its hard to argue with the increase in performance a flowbench can help you find.
And about the rules, You scared me for a minute, I had to go back and re-re-reread the rules again. The intake manifold can't protrude into the port but there is nothing about the exhaust! It least until THEY find out what we are doing...
And about the rules, You scared me for a minute, I had to go back and re-re-reread the rules again. The intake manifold can't protrude into the port but there is nothing about the exhaust! It least until THEY find out what we are doing...
The easy thing to do for the exhaust is to take a small exhaust primary such as a 1 5/8" or 1 3/4" and make the end an oval. Then cut/fit this until it lines up perfectly inside the stock sleeve to hit the perfect transition. Then weld this tube through the flange. That would get around the rules!
Too bad that alot of people don't use flowbenches properly or know how to. I can tell you of a very respected rotary builder who speaks against a flowbench on his website. He has obviously never used one. Everyone automatically thinks more flow therefore more volume. I hate this logic.
08-22-05, 06:45 PM
#23
The thing gets pumped by air like other engines... It seems to me you should be able to improve it by improving air flow!?!?
But the air comes into the chamber on opposite sides... strange things happen in there! Yep, I've heard people poo-poo flowbenches for rotarys. But strange things happen in any engine port and combustion chamber. (We've all triple checked for leaks after something that looks awesome flows like ****) I just figure optimise the things you can measure, which is a lot, the things you can't measure you probably can't do much about anyway. There are things that everybody's engine, port or combustion chamber does but they just don't know it. It could be good or bad its just how its designed, if I can make the stuff I can affect better with a flowbench the guy without one is just getting lucky if he makes more power(or he's cheating)
*disclaimer* I don't claim to build the best engines ever for anything so don't force me to wear nomex to read more in this thread!
rotarygod, the basic premise of the DART info is that fuel and air behave differently than just air. Since a CF of air weighs .03something lbs and a CF of fuel weighs like 40 lbs. Since we inject our fuel late in the intake system the difference would be smaller. But who knows, I've been proven wrong many times, many places. Maybe I'll run fuel through the injectors and intake as I test...... How big would that mushroom cloud be?
Also, do you do the plaster cast method with molds of the port ala Practicle Gas Flow I just bought some fresh mold making epoxy, I've had good luck doing it that way before.
But the air comes into the chamber on opposite sides... strange things happen in there! Yep, I've heard people poo-poo flowbenches for rotarys. But strange things happen in any engine port and combustion chamber. (We've all triple checked for leaks after something that looks awesome flows like ****) I just figure optimise the things you can measure, which is a lot, the things you can't measure you probably can't do much about anyway. There are things that everybody's engine, port or combustion chamber does but they just don't know it. It could be good or bad its just how its designed, if I can make the stuff I can affect better with a flowbench the guy without one is just getting lucky if he makes more power(or he's cheating)
*disclaimer* I don't claim to build the best engines ever for anything so don't force me to wear nomex to read more in this thread!
rotarygod, the basic premise of the DART info is that fuel and air behave differently than just air. Since a CF of air weighs .03something lbs and a CF of fuel weighs like 40 lbs. Since we inject our fuel late in the intake system the difference would be smaller. But who knows, I've been proven wrong many times, many places. Maybe I'll run fuel through the injectors and intake as I test...... How big would that mushroom cloud be?
Also, do you do the plaster cast method with molds of the port ala Practicle Gas Flow I just bought some fresh mold making epoxy, I've had good luck doing it that way before.
08-22-05, 07:36 PM
#24
I make port runner molds from RTV silicone gasket sealer. I do it just like at diyporting.com. When I get the mold out, it is hollow. I then fill it with clay and make sure I've got the shape right. From there I can go back and make the new copy mold out of plaster. This way works good for me and it's cheap. Here's a link to the way to make molds out of RTV. I go back and cover these with the plaster so I have a copy of the original. I use a plaster called Ultracal 30. It is strong stuff. I buy it in 100 lb bags for $20.
http://www.diyporting.com/molds.html
http://www.diyporting.com/molds.html