Im looking for the stock opening and closing degrees on the primary ports. and also the 5th and 6th ports. Im making a correct length custom intake manifold for my renesis and need these to calculate proper runner length. and the exhaust number too would be nice. a correct runner length header is up next...

thanks in adavce.

 

What powerband are you trying to improve? It's going to be hard (extremely hard!) to top the stock manifold between say 0 rpm and 9000 rpm and if you do beat it anywhere, you are going to severely lose in most other places.

 

i understand that. but this is really just for me. I enjoy fabricating parts more than bolting parts on these days. so its more to satisfy the hobbiest in me. also, im using a 4 way ITB from a GSXR as the throttlebodies. they been used a few times on older 13b's and have been proven to be a good match. Im going to do the math and make them about 2 inches to long. then tune. shorten down if needed and so on. test and tune is the only truth.

I had it all set up with a JW manifold and carb set up. but didnt satisfy me, so im going back to my original thoughts of fuel injection and ITB's...

also, the plans are of now (could change, they always do) for this motor to go into a drag car. so i will be making a correct length header that i can also add and take away length. so i will not be needing to compete with Mazdas broad powerband.

I do have a HP goal in mind. and if it is not met, the gap will be filled with a little nitrous. so for instance, if i was a real dreamer and wanted 300whp (not gonna happen) and only managed to squeak out 220 (more realistic). i would add a 100 shot wet wich would put me just above my 300 mark. so no worries here...

 

so anyone know them?

 

thanks rotarygod... if anyone else wants them. here they are.

IO= Intake Open
IC= Intake Close
EO=Exhaust Open
EC= Exhaust Close

Primary: IO= 3* ATDC, IC= 65* ABDC
Secondary: IO= 12* ATDC, IC= 36* ABDC
Auxiliary: IO= 38* ATDC, IC= 80* ABDC
Exhaust ports: EO= 50* BBDC, EC= 3* BTDC

 

and if i did the math right, correct lengths are:

-for 1.5" runners 9k rpm-
Primary: 10.01
Secondary: 11.38
Auxilary: 10.73

-for 2" runner 9k rpm-
Exhaust: 13.69

 

Good luck.

 

thanks... maybe i can set a new renesis HP mark for people to beat. lol... i can dream anyways.

 

http://www.rotaryeng.net/New-rotary-eng.pdf


Peak HP alone doesn't mean squat, and yes you're doing it wrong dreamer

 

^OK, so what am i doing wrong? I take criticism well. As long as its informative also.

 

I redid my math and i did have the primary port off, wich i now edited to be correct in my above post. heres how i did it (using rotary gods write up on rx7 club) :
If im doing wrong, please correct me.

ex: (exhaust)

L= ( (1080-EPD) X 650 / (RPM X RV)

L= ( (1080-673) X 650 / (9000 X 2)

L= ( (407) X 650 / (18000)

L= ( 264550 / (18000)

L=14.69

runner diameter is 2" so i subtract half the length of that to get a final answer of 13.69

 

Lets see if you can add 2 + 2

Q: what do you get when 350+ hp intake ports are coupled with 260 hp exhaust ports?

 

Very hot exhaust ports.

And **** all midrange.

 

Yes and still only 260 hp

 

what is your problem? alls i asked for were the timing degrees, and you get all fired up after i have them.

drag motors and auto-cross motors are set up completely different. build yours, let me build mine.

 

^ He's just pointing out that it's not worth changing the inlet unless you've done serious work (like PP exhausts for a drag motor), you just loose out on a chunk of midrange for very little up top, even I haven't changed it, and we don't see below ~6krpm after 1st gear.

 

well-- i did noticed that the 6 port intake (upper and lower ) has different length runners for the apv port when you compare the front to the rear. Or maybe I am just a crazy old man.
Team is right--but a resource for ya may be with the airplane guys using our engine --they make all kinds of intakes for their powerband requirements.
Good luck and share what you fine out.
OD

 

well today i compared the rear iron of the 4 port and 6 port.

i found out that the 4 port secondarys are actually larger than the 6 port secondarys. i previously thought they were identical. and the runner is placed slightly higher on the 4 port plate.

because im not planning on using the 4 port plates. im going to make them my test mules. im going to enlargen the secondary port to about the size of the port as far as possible. add a bridge to that and see if its at all possible to bridge the exhaust port. if i ruin the plates. it dosnt matter cause i basically got them for free and the only way to know is to try...

i dont have a degree wheel at the moment to measure. but maybe someone here already has the timing numbers for the stock 4 port?

 

My problem? LOL.

FWIW, I'm a long time lurker on RX7Club and have been following your "I got plans" Renesis threads since they started. I know what your goal is and my "you're doing it wrong" observation sticks to the wall regardless. Unless you're planning to install exhaust semi-PPs in the Renesis housings or use 13B housings instead you will never make serious NA power with this 2-rotor engine. Even then, you still have the known sealing issues to deal with if you stick with Renesis rotors.

Yes, I have big plans too, but unlike yourself I'm not posting anything before it's time, let alone posting the same threads on multiple forums about what I'm going to do some day while ignoring people more experienced than myself.

Why don't you start by reading the link I posted above. It will save you from asking any more questions about where you can find information that's already been provided to you. Paying attention and hearing what the knowledgeable Renesis engine people here are trying to share with you will accomplish more, faster for you than taking the dense, hard-headed approach.

Post less, read more, search more ....

 

i post my ideas and plans in a few places for 2 reasons.

1. i take everything into consideration. wether i believe it to be true or false. so i like to have as many open minded opinions as possible because it might help me to think of something new. calm down, dont take things so serious.

2. everyone knows a high post count works wonders with the ladys. i once got it on with hot twins cause they heard i had over 1000 posts on rx7 club.

also the major things i have done to the motor have not been posted up or discussed. im keeping them to myself for now. maybe this is why your a non believer. im a little more experienced than you might think. not to say im a rotary wiz, but i know a little something.

 

and you think people can intelligently answer your intake questions without full disclosure?

all I know is you keep going on about larger intake ports, bridge porting, etc. and this isn't the issue WRT the Renesis power output

 

just know that things like Devcon and JB weld work wonders when you know how to use them in a race only motor...

 

I actually need to go back and edit or maybe just delete that intake runner length thread from the 7 forum and start over again. The thread itself started getting into other things that weren't accurate so it gets misleading pretty quick. The main post also needs to be updated as there is a simpler way to figure it all out that is probably a bit more accurate.

 

I dont think you should delete it... its a great source of info and a big part of fabricating a manifold that most people leave out. I found it pretty accurate as long as you know theres always variables. as in building a manifold for 100* weather at 5000 feet elevation Vs. building one for 75* weather for sea level. test and tune on a track or dyno is the only way to get a manifold perfect. math just gets you in a close range.

 

you are not thinking about doing a variable lenght intake runner are you?
Airplane guys have experimented with different lenght/diameters.
This will be interesting.
OD