ATOMIC

Hey guys,



I am new to Nopistons.com, anyway I would like to hear your guys opinions on the following....



I live in a strange little country called South Africa and I have been building rotors for about 10 years now, and to answer the question before anyone asks it, NO we don't travel by horseback to and from work and there aren't any lions or other game roaming the streets of South Africa!



I race on dirt ovals In SA with a Winged midget (I think you refer to them as TQ midgets over there, correct me if I'm wrong ) We don't race with Hoosier's or any of those huge tyres the guys use in the States or those fancy differentials or those lightweight wheels. Normal diff's, street tyres, normal road wheels. This is a sport for us poor folk over here!



Onto my question, I would like to hear your opinions of what type of motor to use, P-port or side port? My dad raced for about 4 years with a 13B s5 turbo bridge (turbo removed obviously) without ever opening the motor and one of my good friends has been racing a P-port I built for about 5 years now. Our tracks range from 400 meters to a max of 800 meters racing line and we require a motor that has allot of midrange to get out of the corners BUT we don't want to much wheel spin. So.... strong response, but the power delivery must be very linear to keep traction on our cheap tyres. Just keep in mind we use IDA's and distributors, no fancy electronics!



I know most of you guys on here are used to building serious motors with amounts of money that we in SA would regard as insane, so I was interested in your opinions, just to get an idea of how you guys would have done it. Very curious to see some opinions!



Cheers

Charl



PS. I attatched a pic of my car when I was building it, please keep in mind this was done on a VERY tight budget, so don't laugh!

blandry23

Here's a website that might help you make your decision. I personally don't have experience with any type of porting but leave this on here for a couple more hours and your gonna start getting people who do. Ain't gonna laugh at your project, I think it's pretty badass. As long as she works and does some work on the track it doesn't matter what it looks like. Buy anyways, here's the website, hope you get the help you were seeking.



http://autospeed.com/cms/title_Port-...3/article.html

fc3sboy1

cool car. there was a guy in washington state that ran a 4 rotor in a super late modle and did really well with it.

j9fd3s

that's neat! back in the 90's the printed mazdatrix catalog hinted that oval racing and rotaries is really good, but i think the rotaries got banned, its too good!



anyways to answer the question, i dunno. i've driven big BP's and i have a PP car, and i think it depends?



i've had my car at the track, but its all corked up, and the carb tuning was close enough. i'm in between jets so its a little rich. powerband all corked up is like a truck, it starts pulling @ like 3k and runs out of breath around 6500. easy to drive, but high rpm part throttle it didn't like, it wants you to be 60% or more.



the BP car i drove, actually did 230rwhp9600rpm. it drove really well, he spent a LOT of time on the carb. powerband was longer (no corks!) 2-10k, but it felt flatter than the P port.



i should mention that the P port is a 12A, and the bp was a 13B. other than that very similar setups, both carb+distributor, his was a holley, mine is IDA. same trans/rear end. his was in an Rx3, mine is in an 82 Rx7, but i have no interior, so weight should be close



so i'd think either the BP or the PP would work really well. the bridge can use any intake manifold, the P port you have to fab. there is also a little more work to cut the P port vs the bridge. the BP does hinge on the size/shape of the port, you can probably go too big, and you can go too small

ATOMIC

Thanks for the replies guys, nice website, thanks Brendan. j9fd3s, rotaries aren't any good at oval racing at all..... they're bloody brilliant! Nothin like nailing a piston "powered" car on the outside line! The thing is, I've raced many motors, from turbo on the dragstrip to bridge & P-ports on the oval in the saloon classes. I just can't make up my mind as to what motor I'm building for this toy. Intake mannifold and porting isn't a problem as I do EVERYTHING in-house. I was actualy hoping someone would say something that would me decide on a port job. I just have to decide, I've allready got a set of bridge ported irons and as set of rotor housings that I P-ported 2 years ago. I think its time I decide ! Any further sugestions welcome!

thatpoorguy

Are you running it on alcohol or straight gasoline? I always wondered how a rotary would do on straight alcohol. In my mind I think it would be beneficial due to the cooler burn temps and lower likelihood of detonations.