crispeed

It's porting related mainly the result of overlap. Seriously there's no easy solution for it. The problem mainly exist around idle rpm 1500 to 2000rpm and very light load/high vacum cruise at lower rpms also.

Depending on the rest of your setup you're probably better off using the stock turbos and sticking with a SP. Auto X is mainly low rpm off throttle to full throttle short blast situatons which normally suits the stock setup but that also depends on the particular application.

fdracer

this conditional information would've been good to know to begin with to focus the scope of this thread.

the answer is still, it depends. if you have a severe restriction somewhere else in your system then a bp won't help much. if you have a setup that could benefit from increased intake flow then maybe a bp is the way to go. maybe you should post the rest of your setup.

personally, i wouldn't even bother porting the thing if it's mainly for auto-x.

Boostmaniac

I don't go below 4k rpm almost at all on courses. I have always thought a bridgeport could be done that would be beneficial to a turbo setup. I am willing to experiment with some different ports if need be. I don't mind cracking a motor open to swap out irons. I think there is some unused potential in racing with a bridgeport. I noticed on your dyno that you did with a SP and then did the BP to it on the same setup that not only did you make more power, you had ALOT more area under the curve. I could care less about peak power, that's for dyno queens (no insult intended). I am about more usable power everywhere else in the powerband. I think a bridgeport may be the way to go.

I am also going to start looking into the different styles of bridgeporting. I know there has to be a way to do it to increase the streetability of the port itself while still maintaining it's positive flow characterisitcs.

For those of you out there that street your BP motors. How do you like driving them while toodling around town? Is there anyone out there that has good low end response or good off boost driving capability?

Thanks.

-Maniac

Boostmaniac

Yes, I did think that common sense would take over and everyone wouldn't assume I was running a professional drag car.

Increased flow is always a good thing. An engine is a glorified air pump, the more efficient it is the more power it can make to an extent. That was like asking if I would be interested in making more power. As far as I am concerned, everyone's setup could always benefit from a little more intake flow (without the sacrifice of charge velocity).

And why the hell would I want to restrict myself with stock ports? Is auto-x not glorious enough to put money into a car to make it faster? I have absolutely no idea why the hell you would make a statement like that. That is almost the same as saying I wouldn't even bother porting the thing if it's mainly for drag racing. I drive a TII not an FD. I need ports.



Crispeed, i also said possible Nasa events so there is a good possibility of sustained high revs. I'm not trying to build a motor on paper right now anyways. Alot of what I have heard so far has sold me on the potential of the bridgeport but I am still more than open to soak up any more information that will come my way.

Crusader_9x

Hey, you asked about low rpm hesitation and low rpm power and such.

I have a half bridge port and I daily drive my car. As far as the low rpm bucking or hesitation goes I never really get that as bad as I have read on here. Its only under like 3k rpms and on VERY light throttle application. When I say light throttle I mean on flat ground just barely using the gas at all.

I got a gain in low rpm power and drive around town with the HBP. I did have a local not well known large SP in the previous motor so I cant really compare to stock ports at all.

I also did not get that great of gas mileage before hand so I did not experience a big loss in mpg.

If theres anything else I can do please ask.

Boostmaniac

That is awesome stuff, exactly what I was looking for.

Stock ports suck, trust me. My friend has some pretty extreme Streetports and it drives much better than my car. What are your feeling between your 2 motors. Do you like the HBP or the SP better? And at what rpm are you idling?

Also, how is partial throttle to full throttle performance?

Thanks.

-Maniac

Crusader_9x

My car idles at 1400 rpms. I definetly like the HBP better but at the same time I did not have a real good street port motor so its kinda hard to compare the two.

Theres a long story on the SP motor but basically its a local guy that screwed over a bunch of people then disappeared. When I got my motor rebuilt and went HBP i was informed that the old ports were all jagged/sloppy and to big to reuse.

On the throttle thing, as soon as you give it enough gas to even remotely start gaining speed its fine. From my experience as long as theres some load on the motor its fine. Its seems to be that in between area of very light to no load is where it bucks or chugs, if that makes any sense?

Also i have all solid mounts, motor, tranny, and so on so that could also be part of the chuging or bucking it does.

Crusader_9x

Here i uploaded the only video i got with some of the chuging or bucking that it does when your just tooling around town.

http://video.google.com/videoplay?do...19846606838685

AlexG13B

iTrader: (7)

its a big bridge cut?

Boostn7

It is porting related due to the overlap and tuning wil not make it go away.
At low load/idle overlap causes the exhaust to mix with intake resulting with a hunting engine..........bra-bra-bra-bra.
Running a half-bridge (sec's) vs full bridge will help a bit.

If current gas mileage is 11 mpg, it will definetely be worst w/ bridge ports.

Again....anyone in particular you're refering to ???
FYI: I was running a daily driven TII with half-BPs back in ~98-99 thanks to Crispeed:-)

Street porting has proven itself and needs no defending.
fdracer said it best "from daily drivable twins and singles to big hp street/strip cars to all out drag cars, a sp has been a proven to support anything you can throw at it."

Crusader_9x

If that was directed at me then here is a link to some pics.

http://www.propichosting.com/Album.aspx?folder=501408

Boostmaniac

I have thought about a half bridge, but I still think tuning can fix the majority of it. The only way to find out for sure would be to extensively test and tune.

Why? What information are you basing this off of?

It's funny you thought I was talking about you. I was referring to all of those that provided no information whatsoever other than someone I know hates bridgeports. I can see how you kinda fit into this category but I wasn't trying to single you out specifically. If I was, I would say something extremely concise like I don't think your dick measuring contest with BDC is either impressive or needed. He posted up some information on porting and he thinks he doesn't have enough turbo. Regardless of what he thinks you seem to want to contradict him at every corner while he still provides more information. That's all well and good and extremely childish, but that's not the reason I started the thread and it's not what I want clogging it up. I understand you think the streetport is the end all of ports regardless of what you see and I am fine with that. I want something different and the bridgeport provides what I am looking for. So instead of instigating in general douchebaggery and trying to make everyone that runs bridgeports feel stupid for doing so, contribute useful information. You don't like a bridgeport? Why? Do you have pictures of the ports used? What was the intake timing of each bridge? Could less overlap have provided you with a better ride? This is what I was looking for, not Captain Jackass ran a 1.5 second quartermile at the speed of light while using a streetport. I could honestly give 2 ***** less.

I'm not making a dig on streetports. In fact I intend to build a motor with a streetport for purely daily driver purposes. But my "strip" doesn't go straight for a quarter of a mile, it has turns. Sure I'll run at the drag, but my mission is to build kind of like a jack of all trades. Most importantly, "I" want to like it. I could care less if you think I am using inferior ports or you think I could go faster with a street port. If "I" have fun in my car and "YOU" have fun in your car, we are all winners.

So, basically, I want to hear about your bridgeport car. What exactly didn't you like about it. This is the info I want to hear. I would like to see pics of the ports if you have them. I want to try to start taking the "mystique" and guesswork out of bridgeporting for the less technically apt. So if you can tell me anything about your setup, that would be a great start.

-Maniac

blitzboy

more info on my half bridge, mine idles at 1300rpm after much trial and error with the air bypass screw and throttle linkage idle screw, no much bucking to speak of, cruising around town I get 15-18mpg, last week I mananged 25mpg!!!!! on the Motorway of course at a Steady 60mph. But Nailing it boy oh boy does that fuel needle head south haha probably 8-9mpg.
I found I can really modulate the grip and power through the throttle pedal very very very responsive very similar to a highpower NA sort of control, ideal for the twisties
Having owned both SP and now half BP, I will never go back to SP as I just luv the responsiveness of the Half BP on the twisties and on a circuit track

RETed

Got dyno graphs?


-Ted

fdracer

wtf, i don't really get the hostile attitude, no one's even said anything negative to you, we've all just shared our personal opinions. even crispeed suggested going w/ a sp, are you gonna call him a jackass too?

yeah good luck getting that info.

are you dense? go ahead and try running a bridge through stock turbos, exhaust, and intake system and see how great it runs.

rotariesrule

douchebaggery

lol.

i gonna tell my friend, "don't bring your douchebaggery in here".

pluto

I think you have already made up your mind on what porting you want. All you are really looking for is comfort from reading what everyone else think to reassure your decision. Seroiusly, we have at least 4-5 engine builders in this thread telling you not to go with the 1/2 bridge since the negative effect outweights the gain in hp. Those who tells you is fine were properly had the small 1/2 bridge engine that only provided you with the sound effect more than performance. Here are some facts for you based on personal experience

Pro:
more hp overall (maybe by 5-8%, if porting is done correctly)
aggressive idling making it sound more race ready
faster spool up (if porting was done correctly)

Con:
harder to start when cold
higher idle
higher coolant temp
poor light throttle (If I was crusing at 70mph, the speedo will bounce between 70-74 because of the porting and jerkiness from the overlap)
engine life
harder to tune
more fuel consumption
Louder (if you live in a suburb, your neighbors will hate you)
reversion


There you have it......

Boostn7

OK, good luck.

Because I experienced it and so did most when they went from a street port to a
bridge port. Its one of the negatives of a high overlap port.

Its' even funnier how your an arrogant POS that obviously does not need any help !!!
You started a thread asking for eveyones opinions and after 170+ posts you crawl from under a rock and resort to insults for no apparent reason.
Did anyone on here said anything negative to you ?
You need to go back and re-read the whole thread, since you're missing a quite few facts and completely making a jackass out of yourself.
BDC posted two dyno runs:
SP making 424.4rwh @ 15psi
vs
his most recent BP making 439rwh @24psi or 378rwh @14psi.
Now, anyone with any common sense could see which port is performing better based on his own data.
So I'm extremely childish by pointing that out !!!
He was NOT turbo limited since both Crispeed and Pluto made very close to 500rwh with same 60-1 wheel.
If you don't give 2 ***** then go back and crawl back under that rock you came out of.

I've wasted my time and you're simply an idiot and a real douchebag for ruining your own thread.
I'm done here.

BDC

I wouldn't mind responding to these. I've got 4 years experience in tuning and daily-driving an HBP with a great deal of that tuning focus on low-end type stuff, MPG, as well as anything else to keep it "streetable". Perhaps others with my HBP-tuned motors will chime in and lend their honest thoughts.

It seems to me taking the jump from any stock/street port to any kind of bridgeport, even a half-bridgeport with very small cuts, yields the biggest jump in terms of overlap. The big jump will automatically yield an earlier and more aggressive boost thresshold as seen on both of the dyno comparisons provided in this thread thus far. I think peak power is increased as well, but only in terms of potential as with the advent of high overlap, there's a greater need to make sure the turbo is sized properly for the setup. Contrary to what Boostn7 said, on my own car, I had no idea that the 60-1 HIFI was running out of steam. It's pretty clear up at high RPM that the motor was able to outpace and out-demand the compressor's ability to deliver. Comparatively, on a stock or street port, this isn't nearly the case.

The idling... I think that's the first thing that people notice. Even though it's admittedly a bit more troublesome to get set right when tuning with a standalone for TPS calibration, zero throttle fuelling at 0% throttle, and hard-idling the throttle body, I think it's a plus and as Steve says it does give that racey kind of sound; it gives that kind of throaty, V8 hot-rod sound version for a rotary.

Reversion already exists in a stock motor (look at the inside of the outer runners on your manifolds) so I'm not sure how exactly that becomes a con. With respect to AI (auxiliary injection), I can see reversion actually being a plus, in theory.

Higher idle -- This isn't a con whatsoever, even though it might be more difficult to get it set. Once set, it's a non-issue. It can also be a plus for those of us who endeavour to use an underdrive crank pulley -- a higher idle won't contribute to the negative effect of spinning the alternator too slowly at lower idles, producing a hardly-effective alternator.

Higher coolant temp -- I'm not sure where this comes from, but I've never seen any evidence for this on my car or on any others I've done. Theoretically, I can see the merit behind this, but I've never experienced it before.

Harder to tune -- With a few things, I think this is correct -- it's more difficult to get the idle set and trimmed well, it's more difficult to get cold-starting and cold-operation right, and it can be more difficult to get the primer right. But otherwise, with the time I've spent refining the HBP for street use not withstanding, I don't think it's any more difficult.

More fuel consumption -- Admittedly, at lower RPM's (I'd say under 3krpm), there is an increase in consumption, but alot of it can honestly be tuned out. Speaking of fuel consumption, did I ever tell you what kind of tank mileage I got on a tank once driving from here to New Orleans, 80mph in 5th gear? Series 4 Turbo tank -- 300 miles. I normally also get about 220-240mi out of a tank when driving around town.

Louder -- True. Much louder. 50%+ louder. I use a silencer for long drives.

Engine life -- I've saved this for last, as this is one of those questions I get asked when someone asks me about bridgeporting. I think some of the stigma that comes along with this goes to two things -- the overall thickness of the remaining bridge once the cut has been made as well as this notion of burning water.

First, the burning water thing comes from when a J-Bridge is cut and not a traditional bridge. A J-Bridge will extend into the inner o-ring land and then create a problem with sealing the water jacket from the chamber that has to be rigged a certain way with respect to cutting the o-ring and "re-sealing" it. Depending on how the "fix" to the problem is done is what determines that part of its reliability.

Second, the thickness of the bridge:
Depending on the thickness of the bridge, it has the potential to crack I would think theoretically from the on-off heat cycling of the metal. It's a thinner mass, so it strikes me that it'd have a higher risk of cracking. But, in my experience, I've never one time ever seen this happen, even with a bridgeport I did nearly 3 years ago on a still, daily-driven car that had a thickness of 2mm x 2mm x 2" length. The bridges that I cut are considerably thicker than this:

http://bdc.cyberosity.com/v/EnginePo...geViewsIndex=1

They're left at about 0.230 to 0.250" in width, depending on the width of the eyebrow I cut. As you can see, plenty of metal left, and after teardowns of motors with that kind of bridge, not a single shred of evidence to suggest a reduction in engine life due to a potential crack or some other structural failure.

That's my $0.02 cents on all this for what it's worth. My final thoughts -- I am saying that with a well-researched, proper tune, with bridgeport cuts that are conservative in size, this combo can be easily made streetable with little downside while still yielding the pluses of high overlap on a turbo setup.

B

Boostmaniac

I haven't completely made up my mind yet between full bridge and half bridge. As for looking for comfort, this is the wrong place to come for that. But from all of the first hand knowledge that has been dished out so far, I can say my reluctance to go bridgeport has been reduced greatly.

Ok, something that hasn't been covered in this thread. Engine life. This is extremely important to us so what is the average life expectancy of a bridge ported motor? What normally goes first? Does the bridge crack or do the seals die?

Boostmaniac

No hostile attitude, what I was referring to wasn't people's personal opinions. There have been a few individuals that have been coming in and mucking this thread that might honestly believe they are God's gift to the rotary engine. I get tired of watching bickering in a thread where it is not wanted or needed. I know I should expect some bulshit in this forum, but this is my thread, I am free and I am over 21 so I can do or say whatever I damn well please in it. Don't come in to one of my threads and act like a dick and not expect me to make fun of you.

And no, Crispeed has dropped a massive amount of information in regards to porting and I have already thanked him in a previous post of mine. He suggested to go SP, I want to know why. I'll play Devil's Advocate to get the entire story on porting.


Thanks for being so helpful.



Why in the love of god would I do that? What would possess you to think I would even remotely do that? I think I might not be the dense one here... If I do go bridgeport, I would build my entire system around it to support the increase in flow and overlap. Where did I ever say I would use a bridgeport on a purely stock setup?

crispeed

Was basing that on the fact I thought you were planning on using the stock turbos and also not knowing exactly what your operating conditions were.
The way I see it go ahaead and try the BP. The only way to find out if it works for you. I personally have note done a BP with stock turbos so I cannot comment on it's performance. I hope you've allready tried a SP so in that way you can actually base your findings on the differences of both porting types. I hope it works for you.

Boostmaniac

Honestly, if that was serious, thanks.



I had horrible gas mileage because of a shot 02 sensor. Do you really think I should expect less than 11 mpg. (11 mpg was a mix of city and highway driving)



The rock I crawled out from was being bed ridden for the better part of a week. Thanks for reading my post where I apologized for my lack of attendance. I have read the entire thread and I believe what I stated was right on the mark. Hell, the guy I sit next to at work read this thread and stated the exact same thing before I even made that post.

I see the hard data and the first thing I thought was that it was weird it took so much more boost to produce those numbers. Since Crispeed and Pluto both made more power using a similar turbo it would lead me to believe that something is obviously different between BDC's motor and the other two. Perhaps a porting difference, tuning, intake or exhaust setup? I don't know the answer yet but instead of asking these obvious questions the first thing you point out is that he is wrong and he has a lot more left in the turbo. Now, based on the data, the BP is performing better seeing as it is producing bigger numbers, but it is less efficient because it requires more boost to do so. Those are questions an intelligent person would ask, instead you have spent the better part of 10 pages trying to prove him wrong. He thinks he is turbo limited? What do you care? Maybe the motor requires more air thus requiring a bigger turbo? Anything is possible. Just because one person made it work doesn't neccesarily mean the other can make it work.



Yes, you have wasted your time and almost everyone else's here. The true idiot here is apparent and this thread was ruined pages ago. This is my attempt at salvation.

Thanks for visiting, please don't come back.

-Maniac

Boostmaniac

True enough and your reasoning behind it was rock solid. I can't fault you for the fact that I didn't post up enough information. I am currently running stock ports and I have sampled a great streetport done at the hands of Kahren in my friends car he is currently tuning. It drives great but I just want a little more meat in the powerband. The turbo I would like to use on a bridgeport setup would be a 42R, but I am keeping my eyes on that possible 40R hybrid someone has been talking about. I'd gladly sacrifice top end power for a more efficient powerband and quicker transient response.

Bottom line, I am trying to carve the line between a daily driver and a track monster. It will be a fun project.

Sorry about the lack of info but this thread was intended for someone else's viewing pleasure.

Boostmaniac

So BDC, in regards to that dyno, why do you honestly think it took so much more boost to make those numbers? Did you ever get to dyno the motor with a different turbo or setup?

I just want to put this argument to rest once and for all.

As for your post earlier, have you had a chance to speak to your past customers that had a bridge or half bridge? Do you have any feedback whatsoever in this department?

Thanks guys and keep the good info coming.

-Maniac