Check out my sig...
5-speed - Rebuilt Streetported Engine - Custom airbox with K&N Filter
Racing Beat Downpipe - Racing Beat Presilencer - TII Secondary Injectors

Should I be losing to a Neon R/T? He had a crappy launch (mine wasn't good either) and he beat me by 3/4 a car to 80.

The guy who rebuilt my engine put TII injectors in the secondaries. I feel no pull after 3800. I have only ridden in 2 RX-7s ever besides mine and they were both in crappy shape, but they both still pulled after 3800.

Am I expecting too much out of my Vert? Check out my sig and tell me if I am.

 

vert? no turbo conversion? Your mods?

Maybe, maybe not... Close race though.

*edit* Streetport too? Must be the weight of the Vert killing you.

Jarrett

 

put the stock injectors back in. the big ones are killing you.

and make sure your 6 ports open.

 

dude, that SRT neon is fast!! ouno though, good luck. oh wait.. are we talking about the same neon?

 

No Way! Not SRT-4. The R/T. They run 15s i'm told.

 

I think if you have TII secondary injectors installed without leaning out the upper rpm range (with an S-AFC, for example) you will run too rich in the upper rpms. You say the car does not "pull" above 3800 RPM, which is when the secondary injectors start to come on line. So if they are injecting too much fuel, you will feel a lag in that upper rpm range.

Even with stock NA injectors, I have heard of people needing to lean out the upper rpm range on the S-AFC because of the stock computer's slightly rich fuel curve toward the top end.

 

if u aint got turbo then why do you have a downpipe? just curious..

 

I bought my downpipe from Racing Beat.
Here is the link.

http://www.racingbeat.com/FRmazda2.htm

This Down Pipe* is available for custom applications in a 1986-91 RX-7 non-turbo application. (Shown above with optional presilencer) This 2.5-inch down pipe fits either manual or automatic transmission equipped cars.

All right the link won't work, but this is quoted from the Racing Beat Site.

 

Downpipes (I think that is what they are called) for NA's replace the precats. They bolt between the exhaust manifold and the main cat or race pipe / presilencer.

 

Yep,
Like my sig says, RB Downpipe and Presilencer.
I kept the exhaust manifold because I didn't want freaking loud headers. So it goes...
Exhaust Manifold, Downpipe, presilencer, stock catback.

What do you guys think I have for horsepower?
Please specify if you mean flywheel or wheels.

 

How big was the street port? Stock it has 160 flywheel hp, but with a porting job and the exhaust it could be anywhere up to 200.
I think you need your stock injectors back, unless you went bridgeport you're not going to lean out with them.

 

I know this is a little off the topic but I would like to know what horse would I get if I go with a streetport and a full RB exhaust.

Thank You Guys

 

oh forgot to say 90 TII

 

Almost exactly what I was gonna say. Spend $250 for an S-AFC or put your stock injectors back in.

You have gotta love these kinds of questions. Put it on a dyno and let us know

 

The neon R/T isn't a slow car, it's not unheard of for a lightened R/T with all major boltons to bust into the low 14s.

 

The guy who did my rebuild even said that he thought that I wasn't getting as much fuel as I needed. He still has my stock injectors, I assume. I need to get my oil changed anyways. I'll tell him to put the stock ones back in.

 

Neon R/T's around here run low 14's on sticky street rubber.

Verts are heavy, neon's aren't.

Without a header you're probably making no more than 170 at the flywheel. Depending on the quality of the port job with a header you might be able to get up to 200. The stock n/a primary ports are rediculously small.

If you keep the 550's you need the s-afc.

And last but certainly not least.... Do your 6 ports work? If they don't that could be the biggest part of your problem.

I broke loose my 205's with an LSD at 4K. Plenty of pull up top. But I have a frankenstein motor. Finally got 225's on all corners and will be seeing how they handle the power as soon as my paint dries.

 

Hey Jimmi325i, how did you maintain intake velocity and 25+ freeway mpg with such a large primary port (which the TII intermediate housings allowed you to make)? I am guessing that you did not port for large duration or early opening, but just increased the port size. You posted once that you set the opening timing to match the secondary port. What about the closing timing?

I am getting ready to port my S4 NA engine with the RB streetport template and am curious. I am wondering how much beyond the template I should go, assuming that such an act would even be possible with the NA housings' water jacket being where it is. Or maybe I could just find a TII intermediate housing somewhere . . .

Thanks for any info

 

Oh, and what about the injector diffuser plates, did you remove them? I want to remove mine when I match port the IM but they supposedly atomize the fuel. Most cars do not have diffuser plates under the injector nozzles though. So did you remove yours?

Your car is the model of NA achievement for me, I know it sounds corny but you have some great ideas.

 

Sounds like stuck aux ports which can hurt power above 3800rpm. I bet most of you won't feel a difference b/w stock and 550 secondaries-I sure as hell didn't.

 

get rid of those injectors. u still should beat him though dependin on the year rt even with your heavy vert. they run mid to high 15s stock

 

Injector diffusers are all intact. Atomization is where power lies. The slight restriction in the runner is far outweighed by the resultant fuel mixture. Most cars are using the injector to fire a spray of fuel at a hot intake valve too... There is zero chance of fuel puddling on the intake runner for a piston engine. (with the exception of TBI systems)

I'm still having the damn afm problem. It'll probably become worse now that I have better rubber. I'm actually somewhat worried about my clutches life expectancy now. lol It'll be fun though.

Keeping the intake velocity high has more to do with leaving the stock dynamic chamber functional. Only the primaries are utilized at highway speeds. I think the stock porting is simply overly small in an attempt to keep emissions in check and the gas crunch of the mid 80's probably had a lot to do with it too.

I've taken so much heat on here that I really don't want to talk about my car's performance much anymore. I'll get a dyno sheet and we can all see what's the cause of my success. Only a month and a half till the tracks open.

Also, while the power increased with the addition of the 680's, the drivability sucks. Tuning the transition point is a bitch because the ecu maps differently for hot and cold conditions. I live in a po-dunk college town right now so a lot of my daily driving is at less than full opperating temp.

 

Yep, people jump on your *** here and I don't get it. Seems like the turbo guys mostly. Maybe they don't like quick NAs that they can't beat.

So your afm is maxing out? I wonder if you could splice two of them together in parallel, each with a cone filter and a sort of "y" intake pipe, then retune the Safc. The flappers just feed variable resistors and two of them should move roughly half as much for the same air flow. Any descrepency could be tuned out with a wideband o2 sensor.

About your ports, I understand if you don't want to talk too specifically about them. People jumped all over Ito's *** when a pic of his port job was posted. Members of Nopistons.com gave him the opposite reaction; he is considered a porting guru there.

 

I don't spread the word about my design for capatalistic reasons only. I spent damn near 3 mo's researching rotary port design before sitting down to design mine. I'll port your motor for 350, but I also haven't decided if anyone else will ever see my ports outside of looking into the motor after I rebuilt it. 4 people have seen my porting. 3 of them wouldn't know what they're looking at. That was intentional. I've had my car over a year now and only rebuilt the engine in late september.

Ito's design flat out sucks. The durration of that port on the bottom end has to suck ***. There's no reason to remove the barrier between the two ports in the side housing. Granted it makes top end power... but I can start my car from a dead stop in second without feathering the clutch or reving over 1500rpm to get it rolling. Granted thats no big deal when racing, but I don't have to leave it in first to roll a parking lot without stalling.... I'm willing to bet I make the same top end he does if not more. There's no point in removing the barrier to the two port exits unless he also hoggs out the metal between them and makes a new intake manifold with a larger runner to feed it.

As for the afm problem I have... It maxes out under certain conditions and I think I know what happens. (design flaw) When I upshift and close the throttle the afm slams closed. (normal) Then when I complete the shift and hammer the gas, the flapper slams open causing the max reading and subsequent flooding. Two afm's would slow the intake charge velocity, but would also complicate and clutter my engine bay. I have a pic of my filter on another thread about filter swapping here on the first page. I'll be making a cold air box which will seal to the vent in my hood. Two afm's won't work so hot with that settup. I'm looking into getting a hotwire device and trying switching the sensor input type in the s-afc to see if I can get that working with the stuff I already have.

Eventually the stock ecu will be pitched, but right now money doesn't provide for that. I had to sell a nice gun to pay for my rims and tires. It's better than spinning out from bald tires and wrecking the car....

 

Glad to hear that your design worked out for you. I am more interested by the design than the power it makes, I am a wannabe mechanical engineer. I was baiting you for hints of port design . . . it is almost a compliment that you won't tell me anything . . . says that I would know what I was looking at

Anyways, my ideas for porting are to stay short duration but large volume (open slightly earlier and close slightly later) on the primary port, aim the port shape to direct air/fuel at 90 degrees into the chamber in relation to the side iron. Secondaries, open slightly earlier than stock and close slightly later but increase volume as much as possible. The shape if the inside of the secondaries would direct the flow at more like 70 degrees into the chamber. My idea here is to not have both ports aimed right at each other, and having the secondary ports directing the flow in the direction of the combustion chamber movement. I agree about keeping the barrier between the secondary port and sixth port. So you are planning on making templates or starting your own porting service?