Ok, after much debate I'd like some straight answers. My new project FD is under way and I've heard some nasty rumors that I would either like proven or disspelled. Several people have been saying that with a half bp 13B-REW or a full out bp 13B-REW that you will only get 30K-40K out of the engine with your powerband only available from 6K-10K RPM. The powerband I can believe. Well the part about a higher range, but not starting until 6K I find hard to believe, especially since I will be running a T-66BB or a T04Z at 20PSI on high boost setting. So there is myth/truth #1. #2 is the life span. Can anyone confirm that a bp motor will only last 30K-40K miles? Thanx in advance for any and all help guys. Laterz.

Zach

 

The lifespan of bridgeports is generally determined by either bearing failure since many people rev the crap out of them. That part really applies to non turbos as they have to be revved sky high. The other way they fail is when the bridge physically cracks. This is generally a builder error though. It depends on how thin the bridge really is. Don't open the main port any earlier and be careful about the bridge width. If the new eyebrow part of the port is cut carefully so as to not cut into the water jacket (another source of early failure) then the engine should last a long time. Lots of people in the past who used brideports (nonturbo) ran carbon apex seals which only last about 25000 miles when you are good to them. The powerband when done right will actually get better when turboed. The extreme low end is worse as is idle and fuel consumption but once the engine hits boost, power is greater everywhere in the powerband. BDC did a half bridge turbo and noticed much moe power throughout the powerband and a huge amount of torque in the midrange. You won't neccessarily have to rev it any higher. Just don't go too big on the bridge.

 

I'm looking at having Judge Ito or maybe RotorSportsRacing do my porting work for me. As far as the quality of craftmanship I'm not worried abou that. But I was just wondering why I keep hearing the 30K lifespan for a bridgeport. So you're saying that it's not entirely true? By the way, thanks for helping me out here.

Zach

 

Anyone?

 

yeah maybe 30000 racing miles........

its all to do with how much load is being put on an engine the more load you put on it the more components wear

 

I've heard of a monster port 13B lasting 13 *years*... mind you those are "supposed" to last 6 months or so before the water jacket starts leaking into the intake port.

I guess that engine didn't get the memo.

My streetport lasted 23k, does that mean all streetports last 23k? No it means I built a shitty engine and I abused it. I'm sure that if I sprung for the (much more wear-happy) carbon seals that it would have lasted *longer*. Even though the carbon seals are *supposed* to last 20k or so, which is where all the "these engines will only last 30k" storeis come up.

Well here's two thoughts... there are people with over 100k km's (that is 62k miles) on carbon seals. Hmm. Must depend on driver habits. Second if you are going with a turbo, A) you will not be using carbon seals, B) you probably care about Big Power and so you will probably detonate a few times whether you know it or not and you will lose engines with some frequency.

 

Fred pretty much nailed it, friend.

B

 

You dont gain much out of a BP on a turbo engine! Only under extreme case's/ setups will you see a major difference!

 

My take...

A "small" bridge not extending into the water jacket is a waste of time.&nbsp Gains are minimal and the increased overlap kills a lot of low end power.

A bridge done right will crack, period.&nbsp I haven't heard of a properly ported bridge that didn't crack.&nbsp If it hasn't cracked within 50k to 60k miles, it's a compromise bridge.

I really don't like to street engines like a bridge.&nbsp The loss of low end is a big disability for normal, everyday street driving.



-Ted

 

Ted, I've been experimenting with these setups for nearly 8 months now and I've gotten some very good results out of them. I was very skeptical myself until I did several of them and found that they're not quite as bad as some people think up-front. What I do is half-bridgeports (mildly aggressive eyebrow cuts on only the secondary intake ports on-top of an already extend-ported motor) and the low-end loss isn't very bad. One thing I do do is keep the primary port outlets small to help retain some low-end charge velocity. The combination seems to work fairly well.

B

 

Never played with turbo bridge port but plenty NA. Ted was right about small bridge, you will get the characteristic of a bridge but the limited air flow kinda hold you back. Go with J bridge than water will leak with in 2 years for sure. The bridge may or may not crack. ( I never crack one and I cut them about 4mm thin.) Generally with about 25-35k mi. of street and weekend track a motor started with new steel seals and cherry housings and gears look like 130-150k mi. motor after disassemble. The side step wear, gear teeth and E shaft surface look like beat 130-150k. motor It will still run good but gradually start to loose get up and response, after 30k literally nothing is reuseable. If you aint teching to 8k or above bridge is kind of pointless.

 

The Ho Mastah cometh!


-Ted

 

Thanks for all the info/opinions guys. By the way, BDC you built a friend of mine's engine for him not long ago. You remember Reese from Irmo, SC?? He is like a big brother to me. I have been in his car for several hard pulls and an Auto-X. I have to say that the way you built his engine was great. It pulls hard from almost everywhere in the rev range. That kind of porting job is what I am looking at for my FD. I would either like you or Judge Ito to port the motor for me and I will be running a T-66BB tuned to 20psi for race and 14-15psi for street. Of course the Haltech E6X will be onboard as well. So Brian, do you think that a porting job like Reese's 10th AE would work? Thanx in advance.

Zach

 

There is a good comment somewhere in another thread about going to more than an extended port, and it holds oh so true, just look back thru this thread and you'll se e exactly what it's talking about

-=-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

it's funny when bridge ports come up 'cos then people start spouting the usual "yeah you don't make power till the tach needle twists off and you can't drive it on the street"

when at the same time people who actually HAVE bridge or peripheral ports say "it makes great power at all RPM and it's very driveable".

and the people with the HARD FACTS say "a bridge or peripheral port is more efficient and makes more torque at any RPM under heavy load with poorer efficiency at idle or low load". (meaning MPG goes down in cruising but at full throttle and under boost it's MORE POWERFUL at ANY RPM compared to stock or street port) Dyno plots prove this.

 

HWO: Shhh, you'll spoil the secret.

I mean... uh. Everyone don't listen to him, the stock Mazda ports are best, if there were more power to be had they'd have changed them.

 

I have no problem with that statement...

-Ted

 

Some people tend to form opinions from other peoples experiences.Theres nothing wrong to learn from peoples mistakes though.

I drive my Bridgeport to work,in heavy 1/2 hour traffic to work somethimes. I enjoy it. It doesnt have many miles on yet,but it slowly accumulates.

I love it.Its noisy,and takes some concentration to drive.I have gotten many tickets for it,but still i enjoy it.

If you want hp,then you have to pay the price .1 : for fuel and 2: for how long the engine lasts.

Karis

Ps : Since when doesnt a BP have to revved to a another world to perform ? Bull! Mine makes nice torque from 4000 rpm..and dont tell me its a mild bridge... 1/4 " bridge is not mild!

 

We just rebuilt another half-bridgeport T2 with a T66 last night and got about 25 miles on it. I won't give out the specs on the ports but the primaries were left small although cleaned up and the secondaries were extended quite a bit with a very aggressive set of BP cuts w/ rotor housing champfering to match. It still seems to be perfectly fine on the street. Heck, I didn't even have to change the map any in vacuum (30" to 0") for it to run. It seemed to start right up, too.

The thing I wonder about is the difference both in driveability (the low-end torque issue that Ted brought up) and MPG with respect to "streetability". I know alot of people, including myself, have a fairly wide definition of what streetable means, but anything that's difficult to launch out of the hole at a stop light, anything that doesn't get decent gas mileage (especially on the highway), or something that's just extremely loud, misses my vote on streetability.

B

 

We just rebuilt another half-bridgeport T2 with a T66 last night and got about 25 miles on it. I won't give out the specs on the ports but the primaries were left small although cleaned up and the secondaries were extended quite a bit with a very aggressive set of BP cuts w/ rotor housing champfering to match. It still seems to be perfectly fine on the street. Heck, I didn't even have to change the map any in vacuum (30" to 0") for it to run. It seemed to start right up, too.

The thing I wonder about is the difference both in driveability (the low-end torque issue that Ted brought up) and MPG with respect to "streetability". I know alot of people, including myself, have a fairly wide definition of what streetable means, but anything that's difficult to launch out of the hole at a stop light, anything that doesn't get decent gas mileage (especially on the highway), or something that's just extremely loud, misses my vote on streetability.

B

 

streetable: your ability to hand the keys to another human and have them drive it with no major issues.

my tr3 is unstreetable, the starter button, choke, and reverse e brake mechanism means its undrivable by people under 40

mike

 

IN that case, I have never once owned a car that was streetable.

Hell even for my RX-7s, the times I have allowed (very trusted) people to drive them, I had to explain how a manual choke works.

"streetable" cannot be that definition, because it's not another human's car. I think it's funny how people with 13Bs and 4.30 gears complain that their cars are not streetable because theyr turbo doesn't build boost till 4000... BOO F'ING HOO. I have a 12A and I pull away from stoplights in 2nd gear (with a taller rearend gear) with no problem and then I shift straight into 5th, bypassing 3rd and 4th, and I have less torque than that 13B does off-boost.

Basically people are a bunch of whiny ******. Try driving a 2800lb car with 1000lb of people inside and a 1.8l, 80hp (on a good day) engine with a torque curve stretching from 3500 to 4800rpm with almost literally nothing above or below that. Then hop into your lighter RX-7 with your bigger engine and *flat as Kansas* torque curve and *see how much you APPRECIATE it*.

 

I leave my keys in my MG almost all the time because I know that no one will know what to do once they get in it. The best is my buddies MG-TC. It is from a different era....
"Choke, what's a choke?" Yeah, its streetable
BTW - I'm not 40, yet.

 

Heh, I'll have a functioning theft deter- or I meant a choke **** in my MG.

 

AND LOUD!!!

 

The Judge Built my Motor, Its a Large Streetport, Ask him what you should run after all he is the expert.