Rotary Car Club - Half bridge port on stock ecu.

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Half bridge port on stock ecu.

So a little history on my '89 rx7 gtu, s5 na

When I got it, it had 145k miles on it, got a rebuild, Ive daily driven it since Nov. 2005, it now has 199k miles.

Ive done a few upgrades to it the past few years,
racing beat mufflers an pre-silencer,
emissions removed including aux actuators and sleeves removed, and vdi wired open,
intake filter w/heat-shield,
clutch-masters stage 2 clutch,
And other misc. things like window tint an speakers.

This car has gone through two alt belts, two drive-shafts, two clutches, and a set of tires lol.
Its never left me stranded but gave me a scare when cruising the mountains one weekend when it had sever cut-out problems.

Now for the bridge port:
Why?
I got a screw come loose in my brain at dgrr'10 when I saw ErnieT's FD brap'n away at the lodge.
Ive always wanted to do a bridge port or something of that caliber but never had the mind (or screw loose, in my case) to actually do it.

So I had an s4 na parts car with a engine that I rebuilt with a large street port with only 8 miles on it just sitting.

I took the s4 engine out, took it apart, added the bridge port, cleaned the engine parts up alittle, put it back together, took the perfectly good running s5 engine out of my daily driver, swapped the s4 bridge port engine in.
And I did all this with no expense. Reused everything.

How I got it running:
At first it would start but not stay running.
My brother was helping me the day I got it running. He happened to have a pair of 550 injectors with him. We swapped them in place of the primaries, also had to swap the s5 injector connectors with s4.
We tweaked the throttle body adjusting screws for the idle. Installed a fuel-cut switch. We had a wide-band o2 sensor to check the ratio's, which were rich all across the rpm range.

It ran like shit the first two weekends. Rough start-offs, bad hesitation at cruising, and it would bog down after 7k rpm's. The first two tanks of gas were guzzled at 11.9mpg then 13mpg.
I took it down to my brothers to install two 50ohm resistors in parallel inline with the secondary injectors. That fixed the really rich issue in the upper rpm's. The 3rd tank of gas was about 15mpg.

It still has hesitation at cruising. Ive gotten used to the way you got to drive a bridge port. Most of the time its got to be on an off. lol. It revs faster than before, and goes faster too. :)

Next comes proof (pictures, etc).
Ill post em up soon. They are also in the link in my signature.

all on the stock ecu eh? sounds like an accomplishment. i may be wrong but it seems like you would at least want to run a piggyback. A BP would be awesome though.

Friend of mine did this a few years back. Ran super hard for a long time. But a simple SAFC would make a HUGE difference.

Its much easier to do bridge ports on stock S4's. If you pop off the casing on the S4 MAF. You can "tune" it enough to be happy. But not to its potential...

Quote:

Originally Posted by GorillaRE (Post 119259)

Why?

why stock ecu? um maybe cause its free?? maybe everyone doesnt have $500+ to drop on a standalone

A few more details:

I just have the s4 block in there, most every thing else is s5, manifolds, etc.
I had to swap the water pump an housing, from s5 to s4, cause the s5 didn't fit with the s4 front cover.
As mention before, I had to swap the injector connectors, I also swapped the coolant temp sensor connectors.

Why? See 1st post.
Just a spontaneous decision, with the backing that Ive always kinda wanted to do this.

In other news, a week ago or so, my power steering pump decides to go loony on me, leaking an making lots of noise. So I took the belt off.

And as of last weekend, I believe I have a hot start issue.

Secondaries after.
http://i184.photobucket.com/albums/x...DSC_0026-1.jpg

http://i184.photobucket.com/albums/x...h/DSC_0019.jpg

The day my daily driver changed, ripped its heart out just for spontaneous curiosity.
http://i184.photobucket.com/albums/x...DSC_0041-1.jpg

The girls meet for the 1st time.
http://i184.photobucket.com/albums/x...h/DSC_0043.jpg

The beast is in.
http://i184.photobucket.com/albums/x...h/DSC_0045.jpg

The s5 manifold didn't fit over this area, so i grind-ed it down. I actually grind-ed a lot more than that.
http://i184.photobucket.com/albums/x...DSC_0048-1.jpg

The bridge port could of been made bigger.
I only made it 1/8 inch. I should of made it 3/16 inch.

I probably will redo it over again sometime. Hopefully nothing will majorly blow up inside.
Bigger bridge port area. Maybe a full bridge. With new water seals, one piece apex seals, maybe solid corner seals. Etc.

Future plans?
Megasquirt, rebuild as mention above, turbo application.

Definitely different and well done.

birdgeport is the way im going for my next engine for my silver 82. Now what im doing battle with is going with either full bridge or 1/2 bridge.

Here's the problem...

You increase the breathing of the engine, but it's still being choked by the (stock) intake manifolds and (probably) the exhaust.

Ask the BP gurus and flow is everything...
There's a reason why they run short intake (manifolds) and big exhaust systems.

This is why people ask: "why?"

Sure, it'll run...
Run efficiently?
I personally doubt it.

I personally think the ports are cut really bad.
"Well done" would not be the words I'd use to describe the port job.

-Ted

^^agreed... but props for doing it on your own

Quote:

Originally Posted by N.RotaryTech (Post 119292)

Secondaries after.
http://i184.photobucket.com/albums/x...h/DSC_0002.jpg

Cat litter? :rofl:

ha ha, I knew reted would chime in here sometime. Good points.

Yeah this engine could have alot done to it beside a redo of the internals.
The main port work was done by me like two years ago, they were more experimental than anything.
The sad truth about this car of mine is that I don't think it will ever have a main goal. It will just be the lab rat of anything I happen to actually do to it.
I mean I have a turbo kit that Ive been thinking about installing. But Ive always wanted to do an NA build. So its up in the air.

I think the main point is this was just a trial bridge port build, and I'm 50% happy with it. :D

I'm gona try to get a video up sometime.

Now im going to say this with caution...

A nice and super cheap way to solve the problem with the stock intake manifold choking the BP and still use the stock ECU can be achieved (i still insist at least using an SAFC). And you will need some fab skills. Or know someone willing to help.

Get an FD TPS, Mate it to just about any TB that you like. Or just use the FD TB also. But i'm refering more to a set of motorcycle ITB's. Make your intake manifold, and an intake (or plenum if using ITB's) with the MAF in front of the TB (or ITB's). done...

When done right, works real nice for about $150...

Check em out.

The day I got it running.
http://www.youtube.com/watch?v=HDzwx2wR1MI

A random day of idling.
http://www.youtube.com/watch?v=Hw8vgDCjfSQ

lol you should said a random day of revving

So Ive been taking it for a drive on the weekends, not in a row though.
But when I do, I Love it!

I now understand why those people that have the "I (heart) my bridgeport" stickers on their rotary car.

Among other reasons i love it...
Just a couple minutes ago I found out that I can make it shoot flames on command. I put a portable mirror behind the car an looked at the pipes while I revved it up.

Something about it. When you see fire coming out of your engine you just can't Not love it.
:D

Well I knew this day would come.
With only 1,200miles on the motor...
Two main problems that Ive had with this engine, are...
#1 The alternator belts are being eaten away, somehow there miss aligned?
They actually broke on me a few days ago.
Its an S5 alternator on an S4 water pump housing. And there is a large space between the housing and the alternator ear in the rear part of it. I just put a grinded down nut in there to make up the space.
I wonder if that's how all S4 alternator brackets are, being shorter than the alternator.
With my S5 I didn't have this problem.

My solution will come when I rebuild the motor again.
I'm going to swap the front cover, and the water pump housing.
Because I found out that the S4 front cover doesn't go with the S5 water pump housing. So after I built the motor I used the S4 water pump housing.

Which leads me to the second problem...
#2. When I built this motor I didn't spend any money at all. Just reused everything.
Big mistake with coolant seals. Even though they only had 8 miles on them.
The car smokes every time I get it started. And I have had trouble getting it running once it starts.

I think with this rebuild I was more concentrated on the idea of the bridge port than the longevity of the motor.

This next rebuild, I'll do everything better.
It still will be bridge ported.