ioTus

iTrader: (5)

How do you like them as far as street driveablility?

I have my daily driver (although i dont use it all the time, i usually catch a ride or ride my bike), which i'm probably going to convert from 6 to 4 port 13b.

I'm wondering what kind of port job to do on it.

BTW< this is from and is going into an 85 GSL-SE.

Peace, Geoff

Judge Ito

Bridge port on a street car would not be the best way to go. Average good Idle is about 1,500rpm's engine almost wanting to come out the car. To keep the noise down you need a really good exhaust system which will kill some of the power. reduce it down to almost stock power. I would recommend a nice street port but it's up to you. I mean I loved my Mazda B2200 pick up on a 6port bridgeport engine I put in it. to me the bridgeport noise is better then music. I had no radio on the truck for that reason I just wanted to hear that brap,brap,brap everyday. Rob from Pineaple racing told me he had a 13B P-Port pick up for everyday use with a 48IDA down draft webber and @ times he would send his wife to go grocery shopping with the P-port pick up...

ioTus

iTrader: (5)

Bridge port 6 port? how do you do that!?!? i want one!

Judge Ito

I just bridgeported the regular 4 ports and left the 5 and 6 port stock. Man that engine use sound so sweet. Racing Beat Prima Flow muffler in the back..

yovo

Soon I'll be porting my 6-port 13B. I plan to bridge the 5th and 6th ports while just doing a mild blending of the lower ports (modifications shown in red on the picture below). I think this should allow better top-end breathing without sacrificing low-end torque. I'll need to enlarge the holes in the auxilary port sleeves, but that shouldn't be a problem. For optimal gains, this may require altering the RPM the sleeve opens at. What do you think of this idea?

yovo

rotarygod

iTrader: (1)

I just ported my GSL-SE engine a couple of months ago. I was going to do exactly what you propose but decided against it since the factory computer won't allow enough fuel on the top end. I'm sure it would gain but I didn't think it would be worth it without a standalone ecu since the stock afm and throttlebody are so restrictive. I could be wrong though. This would however ginve you a good idle with good low speed emission, gas mileage, and good top end if it works. If you try it keep me posted I may just crack open the engine again and do it.

ioTus

iTrader: (5)

Oh wow.

it never even occured to me to do a 6 port bridge port. Thats awesome.

Would my Racing Beat 13b 6 port Street Port exhaust be good enough (free flowing enough) to hand a 6 port bridge port?

Also, do we have any words if the stock ECU will suffice w/ the 6 port bridgey?

Peace

Geoff

HWO

i could be wrong but looking at the pics with the actual port opening/closing timing etc, if you bridged the 6th port piece, you'd only be gaining a couple of degrees (possibly no gain at all) on the intake port opening timing, the whole idea of a bridge port is to get the intake port opening earlier to get more air into it. i would say the performance gains of that porting would be minimal if any.

yovo

hey HWO, i see what you're saying, but it still opens quite a bit earlier than the stock port. Perhaps this design would be better. Check out the picture attached. It's much closer to a normal bridgeport. What do you think?

yovo

yovo

If that's not enough, the auxilary bridgeport could even extend it slightly past the edge of the rotor housing to allow the port to open earlier (using a small notch in the rotor housing).

rotarygod

iTrader: (1)

My one concern with porting the auxillary ports is the absolutely terrible flow characteristics of those ports. The actuator rods are so turbulent and restrict so much flow that by adding Pineapple radiused sleeves you only gain 1% in airflow through that port. Based on that I have to conclude that flow will not be very good through the small bridge. I don't object to that small of a port. You can go that small of a port and still pass an emissions test (in Texas) with a little bit of trickery using a standalone ecu. I think there would be some sort of gain but I just don't know how much. I think a standalone ecu would be the best way to utilize this but I'm sure it will add a little power regardless with the stock computer. Better have a pretty efficient exhaust and not the factory manifold. If it does work I'd would definitely do it. Just a little scared to be the first to try it. Actually someone has most likely already done it but just not posted results. If you do it and get a gain let us know. Just be warned that there are several people on this forum that always demand dyno numbers or else they cry bs! They do it to me alot but what they don't know won't benefit them either. Do it man!!!

Lasse wankel

I have done a double bridgeport on a N/A 13B engine for a rallycross car this summer. It had no sleeves with streetported street and 6 port. The bridgeporting was only 5mm of width with the same height as the street and 6 port. On a 4 port street and standard bridge it flows 110-120cfm@10" But with the bridgeported 6 ports housings it flows 148cfm@10" Anyway, comparing to the 4 port the 6 port bridge is making 275hp vs 259 hp. The 4 port bridge had a 51mm IDA carb and 2 MSD 7AL-2. The 6 port had Pro Spark fuelinjection and distriburless ignition. The 6 port engine was vey peaky with not so much power below 6k but it revved freely to 10k. Also the tuning the primaries length was a pain where the 4 port was much easier. My advice is if wanna go all out stick with the 6 port but if you want an engine that is easier to tune and makes more torque go with the 4 port engine. Hope something of this helps makeing your decision easier!