Kenku

*shrug* Well, that's hardly going to be the last practice housing I do. So I'll see how the epoxy method goes.

Scalliwag

That's the spirit! What epoxy system are you using? Devcon?

Kenku

*shrug* Everyone always says Devcon, but I'm not sure exactly *why* y'know? I hate to parrot things because that's just what's commonly done without knowing the reasoning. Maybe JB Weld for the next practice one if I can't figure out a reason why it wouldn't work... I've... uh... got a lot of dead housings handy to play with.

Scalliwag

Actually they use Devcon because it works. Excellent bond strength, great work characteristics, no noticeable shrinkage, and machines very nicely, and holds up to thermal cycling.
Some epoxies don't work because if they fail any of those characteristics, they fail altogether.

Kenku

Heh, suppose that'd do it. I'd have to check to see if we have any laying around; we've had so many composite projects happen in our barn over the course of my life that... well.

Though come to think of it, that's rather different. Ah well, I suppose it would be too much to hope for to get the engine built without spending *some* money...

Rotortuner

I use JB and it works well. I think people shy away just because it doesnt have a name that makes it sound professional. JB has worked fine for me.

CJG

OC_

i wonder what the Possibilities would be for a turbo PP. you would have to have a lot less overlap by moving the port higher, and i dont think the ports would have to be as big. I was looking around on line and i did find a little blurb about a 900hp turbo PP, this is what was said
"Racing beat's Bonneville racer has a 3 rotor 13G factory racing engine that is peripheral ported AND turbocharged (3 turbos!!), making around 900 hp.
The car is capable of 200+ MPH. Unfortunately to see the engine the whole body must be removed, which was not possible when I visited. (the picture of the engine with the turbos on it is from another magazine-apart from that all photos are mine)"
of course, none of the pictures worked.

maybe you could just find the port timing when the exhasut port closes and the intake opens of your favorite turbo engine and kind go off that for the PP.

I think a turbo PP would be nice since the incoming air has more of a direct path into the cumbustion chamber and doesnt have to go around any tight bends, this should make for a cooler incoming charge.

i think the only thing to figure out is if there is somthing in the way, preventing a port to be cut so theres mild overlap.
what do you think?

REVHED

Many people have done pp turbo's and I think you'll find the port timing is pretty similar to what you'd have on an n/a engine. This is the Scoot secondary pp turbo engine.

600HP CLUB

drool .. semi-peripheral port.. someone needs to try that, seeing that the semi-pp has lesser overlap making it possible to run turbo, but isn't the 3-rotor 6 sec drag racer peripheral ported also like abel?

OC_

looks like that port is pretty high up to me, then again, isnt the port timing different on a PP since its opend at the apex?

Grizzly

Even that will open way earlier than a stock or Extended Port.

Have you noticed that a Bridge with Relived Hosings will open even earlyer than the P/P?

Have a look where the Housing cut outs start to open, does this mean the P/P will have less Overlap?

Chris

BTW, That scoot engine is Amaizing note the alloy Plates etc i would realy like to talk to them maybe even get some of there goodies.

Grizzly

I Relise that this is mainly on the Forced Induction engines but if the Turbo is blowing the Fuel air in wont it have simalar or more Over lap efect?

Chris

Rotortuner

Its been done, a Some of the NZ guys have them and soe people in AU. Also Abels car is not PP.

CJG

rotarygod

iTrader: (1)

As far as I'm concerned, if it ain't Devcon, it ain't epoxy! I've used JB Weld. It is very expensive and takes forever to dry. After about 150 degrees or so it starts to get a little soft. Not runny by any means but just a little pliable. This can cause it to fail by pulling away from the surface it is bonded to. If this is the inside of an intake runner then it is bad news. I have had Devcon in my intake runners in various spots for several years now and have never had any problems with it what so ever. Check out Devcons website for a little insight into a good epoxy. You can even drill and tap it for screws! There is a guy on the forum (Roy _____ ?) who had an engine die because of JB Weld failure when they were used in the 6 port sleeves. That stuff is really only backwoods redneck glue. It has no business being anywhere that reliability is an issue.

Kenku

All righty, thanks. Now I know.

By the way, just random question; I'm looking at making a street engine with the semi-PP thing (like that housing pic I posted) and I'm just wondering what I should be thinking about in terms of turbos. I'm not planning on running anything more than pump gas on a regular basis, so sizing for high boost levels seems impractical... so what, maybe a pair of T3/T4 hybrids? Just thought I'd throw out the question... it's not like I'm going to be going to turbos any time in the near future.

OC_

it seems theres some confusion when we are talking about PP 's overlap, or i am confused. We are useing overlap in the same context as in a piston engine right? when both the intake and the exhasut are open at the same time.

Thats why a N/A PP would be bad for turbo, the intake and exhaust are open at the same time for so long, the intake charge jsut goes through the exhaust before it even has a change to combust! From what i read you want a little of that since the unburnt gas cools the exhuast and turbos, but the N/A pp's porting timing is way off for a good turbo setup.

I did read somthing else where people were talking about a port 'overlaping' a water jacket..?!

Grizzly

You will only realy see the Over lap effect at Low Revs, the Quicker the Engine is Turning the Les time the Inlet charge has to blow out the Exhaust.

Chris

OC_

yes, thats the pont. I would like to be able to idel at somthing reasonable and would want torque. The turbo can handel all the higher RPM power.

Mr BiG G

anything new with ur PP housing project scalliwag? and wat bout u kenku?

Scalliwag

The housings I made for Ken worked great. I found the timing that Paul Yaw posted on his site so I am open for business if anyone wants a set made.

crispeed

Were those housings on the blue motor or the red one!

Scalliwag

I don't remember the color of the irons on that motor. He has 3 motors. One has the Racing Beat pport housings which are easy to tell and the others both look alike. One he got from Jesus Padilla and the other he built. Both of those used new housings so it is not real obvious which set is on which motor.
ken keeps up with all that though.
He had it running on his test stand when I was there a few months back. He was happy with them and said they worked great and won at least one day at the track with them.

Kenku

Well, I thought about the semi-pport idea a lot and... well, I still want to do it. But I decided that I'd like to get my car on the street by summer 2004 so I'm ditching the semi pport and just going with a full peripheral port. Just have to scrape and save for a 'Berg IDA now, much simpler. And boo hoo, it won't get very good gas mileage or have much low end torque... I find myself not caring a whole lot. Heh heh heh heh heh...

Kenku

... oh yeah, and we're getting a *very* good deal on a used Bridgeport mill, so I can even do these things the *right* way.

peejay

You can't apply very much boinger-think to the equation because the applications are fundamentally diffrent.

In a boinger, when the intake and exhaust valves are open, think about it... the valves are right next to each other, and in many cases due to valve angle the airflow from one port is actually pointed into the other port. The piston is pretty much at or very close to TDC during the overlap period so there's no appreciable cylinder space so the easiest thing is for one port to flow into the other.

Now in a rotary... first thing you notice is that the ports are at the opposite ends of the chamber when the rotor is at "TDC" (the overlap period. Second thing you notice, in a partially assembled engine, is that the rotor makes it pretty difficult for stuff to flow from one end of the chamber to the other, because of the housing "pinch". In a nutshell, for any intake to blow out the exhaust, it has to force all residual exhaust gases out the exhaust pipe before it can start pushing new air out the exhaust as well. Now, last time I checked, this was a GOOD thing!

And if the exhaust manifold pressure is higher than the intake manifold pressure, it's about as bad as if you had a streetport anyway. (And you should look into a freer flowing turbo hotside)

PP's can have less overlap than a comparable BP because their shape and position allows them to have less timing and still present as much port area during the overlap period. (Picture just the bridge's eyebrows, vs. an entire peripheral port) Also PP's are better positioned to get air to the middle of the rotor as the port is opening, vs. bridgeys who have to make at best a 40 or so degree turn to get the mixture into the chamber.

I like PP's