I'm the same way about discussing things in my threads

Thanks for the compliments about the welds ... I know a thing or two about welding

Ya, this engine has definately gone through some extensive R&D already lol ... so no one said it was going to be a walk in the park for you :P. As you can tell I'm already down to just playing around with not only degrees of timing but split timing also, so its definetely approaching what I believe is close to its limits with the porting available.

What do you mean by how long are my ITB's? Are you asking the throttle bodies themselves or with the air horns?

As for the porting ... I can't be of too much help ... I'm not an engine builder (yet ) I had it built so I can't be too specific on that. I was told the ports are a bit bigger than average though. The reason being is when I blew up the engine last time (about a couple years ago), when he tried to match both of them together he went a little bigger on both intake and exhaust from what he uses (he has his own templates, he's been racing and building rotaries since the late 70's), the guys around here call him "the bat from hell" lol. Very aggressive driver from trinidad.

What do you think can you do as far power?

I personally believe it could be brought down about 1000 rpm and be able to flatten it out with that 130ft-lb over a broader range a bit. But ya from looking around I'm pushing the same torque as alot of the 13B guys. So we'll see how it goes.

 

I can tell its had some good tweaking to get where its at now. Makes it even more exciting if any gains occur on top of a already solid foundation. I worded the question wrong, I meant to say how long is the ITB intake length, from tip of air-horn to the engine block. Estimated power gains... hmmm. For 90% of people out there, the SDJ header is the wrong length. However, you are a lucky one who is using a non-factory based intake. So using some speculation, I bet your intake will turn out to be roughly 14-15". At that length the SDJ is juuuust barely able to provide some resonation. The convergence angles, and throat diameter will be where I can make some serious improvements. Length too, just not as much as normal. So I will go out on a limb and make these estimates- Torque will go up to 134-135ft-lbs. You may get a mini torque boost in the 2500-3500 range of 5-10 ft-lbs. It will start to ramp up at 5,500 but carry out to 7000 at least. Possibly 7600 if we hit it on the nail the first time. That will place horsepower in the 175-180rwhp range.

 

So am I measuring Primaries or secondaries or both?

If I can reach those levels that would be sweet ... but I'm not getting my hope that high up yet :P

What intake length do you think the SDJ was made for?

Lastly, do you think the principles would be the same for supercharging it? As in the resonance out of the exhaust would still be the same?

 

Great numbers keep em coming

 

Well did my best at measuring out the length ... not sure whether it ended up in the primaries or secondaries ... but its roughly 18" to the bell mouth of the velocity stack.

Here's a couple very old pictures of the setup minus the 1/2" spacer inbetween the upper and lower intake manifold as previously mentioned:

https://www.rx7club.com/attachment.p...4&d=1208145798

https://www.rx7club.com/attachment.p...5&d=1208145798

Excuse the messy look in those pictures, I was just putting everything in that new, freshly painted shell at the time.

 

I dont think SDJ did much thought for the header length. They just made a better mouse trap of the RB header by 1) stainless construction (hotter internal gases) 2) Straighter shot out of the engine before the first bend 3) Somewhat of a merge collector. RB came up with the length in order to work around mazda geometry on the cat. Fallback of reverse compatibility, compromise in design. But for RB it worked great, and 99% of people are not that die-hard. Now onto intake length, the secondary length is where I am mostly concerned. How did you take a measurement? It might be easier to remove the intake. That is if its not too big of a PITA. If you keep the supercharged intake length the same as n/a, then the resonance should benefit. But supercharged rotaries is not something I play around with much. Turbo and N/a share MANY attributes. Supercharger is a mix, because the exhaust is under atmospheric conditions, while the intake is under artificial pressures. On first thought I would think this is badass for high overlap situations, no chance of reversion. But I am far from a authority on the subject

 

I measured it by shoving a tube in there till it couldnt go in further. What I could do though is possibly contact racing beat and ask them to measure it? Then all I have to add is the length of the 1/2" spacer, and the throttle bodies with the air horns.

 

Yeah racing beat should know, but that manifold was discontinued a while ago, so maybe not. If it stopped then it prolly hit the end of the port. Which would be about 2" or so off the measurement

 

Well I suppose i could always ask someone that might also have it up for sale .. either way I could probably find a way

Out of curiosity what part of Ohio are you in? I might be stopping in Cleveland with a friend who's interested in purchasing a 1914 Ford Model T in the near future.

 

Im sorry i just can't stop

 

...wait, what?

 

Just outside of Columbus ohio. About a hour and some change from cleveland.

 

I just got off the phone with racing beat, and he said that the lengths are about 10" for primaries and half an inch more for secondary.

 

And how long are the ITB's with airhorns?

 

I haven't forgot about this yet, I just got really busy since then and we had a lovely snow storm the past few dayys and prob the next day or two, so I'll get to it as soon as things clear up. I currently have over 4 feet of snow on my front lawn from the past 3 days .... I'm still having a blast with it though in the snow

 

No problem, driving Rx's in the snow is always a good way to enjoy the bad weather!

On a separate note, I have been getting emails and IM's about seeing more semi p-port pics. So a few days ago I took some better pics from a recent set we did for a turbo setup. We are starting to have these pre-made and in stock. Also can do the service to a sent in rotor housing.

 

Logan have you done any full P-port engine builds? I know that most PPorts that are done are primarily track focused, which is where alot of people get the misconceptions that they cannot have a nice idle and streetable car with them. If done right with mild-sized ports and not to crazy timing/overlap they can be quite street friendly while still making power. Just wondered if you've ever played around with that just to avoid the complexity of the semi-pport system (not that its really that bad, just curious).

 

We have built a full p-port engine for a customer, but never did a entire setup. Or a full p-port engine for myself. Not to step on toes or sound even remotely arrogant, but there are two types of full p-ports. Ones that are street focused, idle/drive more smoothly, and are not so loud. These are the same engines that do not produce "outstanding" power. Many are below, or maybe a touch higher than what we have done with street ports. Then there are the loud, rougher idling, un-friendly light throttle full p-port engines. These are ones that have the tune correct (exhaust/intake), and produce excellent power. And I know exactly why. Full p-port cant have both. They are incredibly sensitive to all regards of tuning. Pick one or the other. This is why I am focused on semi p-ports. We can get 96% of the power from the best track only full p-ports, but still have the drivability and quiet exhaust of a streetport. Win/win

 

This is perfect timing really...

After I'm bored of the semi p-port/ street port 13b turbo setup in my RX-8, this will have to be the next route as I was orginally going to do a N/A 3 rotor build but decided against... This motivates me as now I can just go to you guys.

 

Cool, we will be here when you are ready

 

This thread is making me want to give up turbo power

Quick couple of questions, for the semi p-ports are you using steel or aluminum in there for the sleeve?
Pros, cons?

What is the cost on the service? to do Semi p-port housings?

What Can I expect out of a similar 13b over a 20b?

And if you dont mind sharing what Lengths did you end up with on your header from flange to collector?

I really love this thread lmao

 

The sleeves are pressed in correct? If so, aren't they cylindrical machined tubes? I would think that unless they are a perfect fit they could move around (in would be the worst case scenario lol) as they heat cycle.

Also what's the going rate to do semi-pp some housings?
-Heath

 

https://www.rx7club.com/showpost.php...4&postcount=21

 

We use aluminum, because it will expand and contract at the same rate as the rotor housing. Cost of the semi p-port service is $400 per housing. Power on a 13b if it was identical to my 20b, would produce 285rwhp. I haven't settled on the exhaust length yet, still adjusting it.

And I am glad you like our work

The link T-von posted sums it up pretty well. If you need more details let me know.
Thanks T-von!

 

I notice that there are two rotor housings pictured. Not one or three.

Hmm.