This is what I was hoping to hear. Keep us posted Chris. I have a couple of plates lying around here I would love to do this to. Thanks.

 

Wow....

I was finally able to get her to idle and not shut off yesterday....and with no fuel leaks .

The engine needs air....so much air....My idle bypass valve(custom made for the new manifold) couldn't hold idle even all the way open....I had to drill a small hole in the throttle body butterfly to get it to idle and man!....can you hear the Brap Brap Brap!...it is very defined...specially with a 4" exhaust . The reason the idle is an issue is not that the porting is too extreme. It is simply due to the fact that the OEM computer still controls the throttle body and it is always trying to idle the car at 800rpm....this is fine normally but "bridgeys" like to idle between 1100 and 1300. I have mine set at 1200 and its perfect.

oh....and the vacuum is at like 10hg...haha...on a new rebuild!...this is common for bridgeported engine.


I can tell that the air demands for the engine have changed. This will require a completely new tune. My friend was there and he took a very short video which I should have later so I will post it here. Now I am waiting for a front bearing so I can put my wheels back on...and then I can start to do some street tuning.

These are very exciting times!

Chris

 

Do you think you will be able to get it to idle sub 1k?

 

props to you man . can't wait to see what that baby will do ...

 

I am sure you could force it to idle between 900-1000rpm...but I am not even going to try to get it that low. It looses the consistent brap and starts sounding eratic with braps in between at 1000rpm and lower.

Bridgeports are meant to idle above 1000rpm, you know this and accept it when you decide to go bridge...I am sure you can force it to go lower but what is the point? It wont be any quieter, it wont affect anything to idle above 1000wpm and it wont have the signature sound...so other that the mental issue of knowing the idle is above 1000rpm there is no reason to try it any lower. If the idle being 300rpm higher is an issue then don't go bridgeport.

Its kinda saying you want 400whp and you want the car to be as quiet as stock....or that you want a turbo but you don't want to be able to hear the whine/whistle of one...see what I am saying?


Chris

 

nice chris, looking forward to vids! I never knew a bridgeport would affect vac readings. Interesting stuff.

 

Thanks to BDC for helping me out with tuning tips...lots changes when going bridge...specially in the timing during cranking and idling. BDC has done dozens of bridgeports so his tuning insight really helps.

Chris

 

just read the whole thread, very exciting stuff. Can't wait to see where this goes...

Chris: grats on getting the car running, keep us posted

 

The next goal is to get the stock ECU to not try and force the TB shut to drop idle when off-throttle.

B

 

can you control that with a flash tune? (Hymee Pro Tuner, AP, etc)

 

I do not know. It would suck to have to get a tuner just with the purpose of setting the idle. Currently what I made works...but the throttle still closes a bit every 30sec or so to try and bring the idle down to stock...but it just goes down to 1000rpm momentarily before it goes back up to what I set it at...its annoying sometimes but its livable.

Maybe someone local can "lend" me a tuner so I can set up the idle to 1200...

Any volunteers?

Chris

 

I still think ya oughta try sticking a small resistor in the TPS 5V output signal lead to fool the ECU into thinking you're still on the throttle when you're off. It'll disable the idle functions.

B

 

Hmmmm, I would think that since you don't have the OE upper intake manifold the secondary ports being open at idle is the issue. This won't be the case and possibly less of an issue for those with the OE upper manifold.

 

Or you could lend me the engine and I'll put it on my standalone

 

Haha...funny...I have a standalone...but the stock ECU still controls the Drive by wire throttle.

I'll think about it though...

Chris

 

That is not the issue....having the ports open would cause issues in the fact that the engine would require more throttle to stay on due to a loss in efficiency but it shouldn't cause inconsistency. This has been done on 6 port engines in the past where all 6 ports are open and the idle and off idle performance leaves alot to be desired but the rpm's are constant. The issue is the stock computer trying to keep the car at 800 when it can no longer idle below 1000rpm. If I set the idle with my bypass when the throttle is not trying to close at 1200 when it closes to attempt stock idle it will drop to 1000rpm...then it will let go momentarily and go up to 1200-1300again...then in a little bit it will try again...so it gets anoying....also, you can see it the % throttle display as it varies at idle.

This was happening to me even before when I had the stock manifold because I was also trying to hold the idle at 1000rpm instead of 800. The change in manifold didn't make a difference.

Chris

 

Chris - just FYI you can change the idle RPM by using a flash tuner.

 

Great...then all I need is a buddy with a flash tuner in the area...hardly worth it to buy one just for this purpose...

any volunteers???

Chris

 

Arent those flash devices "married" to the RX-8 (not possible to use on multiple cars)?

 

it is possible to use Hymee's Pro tuner on multiple cars but he does still need to provide you with a "token" to work with each specific car which he does charge for ...

 

I know you are using a stand alone to push the boundaries on this engine but having used pro tuner I have a feeling you could get a better result with a flash tune

 

My turbo piping/Maf location do not allow the use of a flash tuner, I am moving 3 or more times the amount of air the stock engine moves....it would be complementary but I would not replace the stand alone for a tuner ever...half my sensors/solenoids aren't even there anymore.

Chris

 

fair enough - I think MM was saying once the stock maf was only good to somewhere north of 400whp so I guess that is no good to you even if you could get a stable reading ....

 

Half-bridge Idling!


http://www.facebook.com/video/video....0611040&ref=mf



Chris

 

Sounds good Chris. Now go tear up the road and let us know how it runs.