Why? I do not agree with this statement at all. If you can give me a good reason why a person should not bridgeport and turbo I would be very surprised.

Not trying to be hostile just hate for some random person to read this and think its a bad idea when its not.

 

No failures reported as of yet and given how rare older 13b engines are here and the possibility to retain the oe ecu it makes sense for some people.


Intake and exhaust are unbalanced already, a bridgeport only takes that to the extreme... even bigger intake ports and rather contorted\small exhaust ones.

 

I can't comprehend why anyone would want to retain the OE computer with a peripheral port conversion. Knowlegable engine builders don't believe that welding off the side exhaust port openings as being viable for very long. I came up with a way to block off the opening with metal inserts and cast filling the port to seal the deal, but in the end just doing a 13B transplant makes more sense in every regard. They are so cheap and plentiful that it seems to me that even importing one would still make more sense.

 

BSE you need to move to NZ,

we are literally drowing in pre renny 13b's lol

we are Japan's dumping ground for old cars lol

summary:

want a bridgey?

pre renny 13b/thread

 

Of course you can slap an m400 in there but at that point and pricetag a full PP makes more sense.
The OE pcm is tied to the oe intake manifold. Using both the vdi and APVs lets you retain a decent (still worse than stock) powerband that lets you use the car for transportation without relegating it to full track car witha 6.5k\9.5k rpm powerband and 20hp down below that are barely enough to get out of the pits.

I like the renesis' intake ports and 10:1 compression ratio as well, and finding a fried renny to rebuild is still cheaper than importing a previous 13b and doing the build from scratch with all the new parts required.

We had the exhaust port profiles scanned in CAD. The machinist sends us the inserts and we fill the oe ports and then weld the inserts to the sideplate. It's complicated but after a good lapping and re-hardening the sideplates tend to deal just fine with the new configuration.

It's always about the trade-offs.

@Slidin8: I'm just a noob, there are way better rebuilders out there that would be better to kidnap and import to NZ in a crate

 

for power goals, fuel economy and longevity,why would you want a bridge port, if you CAN turbo. You have to understand the only reason a bridge port exist!!! It's is because of forced induction being banned in some racing sanctions and they had to come up with a way to make more power without a turbo. they did they came up with p ports, and then.. those got banned, so finally they arrive a the worst port combination compromise. huge over lapp, but rather shitty port flow(compared to a full PP). seriously, they SERIOUSLY should have called it the compromise port. for a renesis, keep the stock ports and keep the lean *** idle, and rather good economy and just turbo it to your 300-400-500?hp goals. bridge 13b's (of the rx7 kind) that are turbo'd are usually found making 600-800. probably outside of most peoples ambitions. certainly higher then i care to go. i'm pushing on the n/a frontier.

 

A 400hp renesis won't last more than 10 real track hours.
That's a no go for most of us and in most real federations turbos increase the engine's displacement 1.5 times.

A small bridge with peripheral exhaust ports is the key for somebody willing to increase its power output without making the car excessively unreliable or moody (think full PP...).

 

Subscribing.

 

Subbed too!

 

Well you guys are just in time

 

You know something we don't, 9k? Because withholding information is for suckas and jive turkeys!

 

Yes, I do. Bridgeported Renesis engines are a waste of time and money.

 

Because everyone knows the restriction of the renny is the exhaust ports

 

I'm no genius, but from what i understand the problem in these engines is the exhaust restriction. Thus creating a hot point on the exhaust side, which in turn damages the side seal, and hey presto, your renny is screwed. Is that about right?

Surely then, bridging it will only put more air into the engine, but without being able to get rid of it, and therefore just making the problem worse.

So therefore, would it not make more sense to work on the exhaust side of the engines and improve flow there? I'm asuming that most of you know this, and there is a good reason why the exhaust ports cant be worked?

 

The exhaust ports can't be made much bigger without compromising the coolant passages in the housings

 

9krpmrx8,
100% correct... Pointless thing to do. N/A anyway. $500+ for 5~10 HP. Price not including rebuild, or labor to dissemble and reassemble, or shipping. Could be closer to $1000... Not very efficient use of money.

ReV2ReD,
Only half right. Heat on the side seals is 100% correct. Flow, or the ability to exhaust minimal NA gasses is a moot point. The port has no problem dumping the exhaust. You have to remember that even though heat wise the side exhaust isn't as efficient, it is more than effective enough to remove the gasses for any NA application. There is 47% more exhaust port area over the 13b peripheral port.

Mazda squeezed 60 more NA HP out out the old 13b with the new side ports, and made it more emission friendly. It's impressive for what it is, but don't expect to get any more power out of it. Go FI, or live with it for what it is.

 

Mazda didn't squeeze 60 more hp out of the engine with just an exhaust port relocation.
It's the whole package that's different.

Besides, port area only represents part of the equation. Think about flow and speed. The same engine puts down 15% more power with ported peripheral exhaust ports out of an earlier 13b and the side exhaust ports welded shut...

 

agree with bse50 on this one. Remember it is not just about the cross sectional area--its the fact that with the 13msp engine the exhaust flow has to turn 90% before it gets out.

 

sounds like an opportunity to just drill a hole in the side of the housing

 

That option for a bridgeport is starting to not look like such a bad idea

 

Have a look at the differences between the intake ports of the MSP and all previous 13B's

The intake ports are very big

 

I was being very general, but yes, I understand all those other points. My comment still stands though, you're really not going to get any major power out of the engine in NA trim. I would say that in a perfect world, 250 HP would be a serious stretch, and require 100x more money than it would be worth to achieve. More than it costs to just go FI and be done with it.

 

You're just throwing numbers around.

 

Throwing what numbers around? 250 HP? yes, it's a "big number" to illustrate the point of an extreme limit that may or may not EVER be reached in NA trim in a renesis engine. it doesn't have to be a realistic number, and it's intended to be outside of the current margin of achievable numbers.

The "hunt" for maximum NA power has stagnated for years at 220~230 wheel HP. Can more be made? Who knows... maybe. My entire point is simple, NA power is not a cost effective pursuit. Even in the racing community, to expect more than 220~230 WHP is pretty unreasonable at this point.

As for the 47% more port area, you'll have to take up that statistic with RotaryGod, as he's the one that reported it. Does it honestly matter to me if it's correct or not? not really. Again, all I was doing was illustrating a point to ReV2ReD who was assuming that the stock exhaust ports somehow cannot exhaust the meager amounts of additional gasses ingested from a bridgeport.

I'm not sure why I need to be 100% technical with situations where a simple illustration can convey a message to someone not asking for an engineering quality answer.

 

Throwing out numbers shows that you're just parroting what others say without adding any critical input to the debate.

The hunt for maximum NA hp went over that limit already, just because some racers have to follow a certain rulebook it doesn't mean that their limit is the most you can squeeze out of an engine.

You were illustrating a point to Rev2Red in a shitty way since total port area doesn't mean much in this scenario. You could have a 3sq feet hole to exhaust gasses and a wall right behind it.

Again, stop spreading dreams and myths and start building something to prove us wrong. Most of the guys who chimed in here, from TeamRX8 to OD to lastphaseofthis etc actually tried doing something concrete at some point. What have you done?
I can tell you that Team's narrow point of view is dictated by the use he does of his car, most teams or team owners that chimed in during the years were narrow minded and rightly so, given their class rules. I'm budget and knowledge limited myself but I don't mind rigging up a franken-engine from time to time to see what does what. OD is OD What have you got to add? you had a bridgeported renesis for more than a year now and still can't figure out how to tune it. What real world reports can you produce?