I know im probably gonna get yelled at ;(.
Stealth wanted me to post this up!

We had a big discussion today/yesterday about it. Mainly because how my car performed. Got spanked by purple87lx ;(.

Just don't know if i wanna jump the gun on switching to carb just yet..Idk if anyone has ever been in my shoes. Sooo yeah...

HELP!

 

If your car was stock and you wanted to upgrade, I'd say put a carb on it 100%. Being you already have several bolt ons, I'd say get what you have straightened out. WHOEVER told you that the gt40 intake wasnt enough.... well get advice else where

 

You've got a decent combo.

You first need to get it running correctly and make sure all the voltages are within specs. EFI is very forgiving,.. yet very intolerable with certain things.

When I first put my son's car together I had some issues that I didnt understand. I finally got the motor running pretty damn good with EFI. The cam lopes nice, the throttle response is perfect. Its pretty squirelly for what it is and I am pretty proud of myself for sticking it out. Got some good advice and got it all working. I still want to swap to a carb,.. but only because of personal choice. Not for lack of understanding this time.

You need to do the same with yours. You dont need a lot of tools to figure it out. You need a cheap little $9 - $15 volt meter. A timing light. A couple screw drivers and a cheap socket wrench kit will do.

The most noticeable effect that I saw when tuning my son's car was resetting the TPS. It has an aftermarket TB on it and when they put the stock TPS sensor on it they never bothered to make sure it was adjusted correctly. The TPS voltage was off and out of spec.

Follow the instructions within these links and then see how the car is running.

Ford Mustang Base Idle Reset

Summarized/Corrected Base Idle Reset Procedure

Ford Fuel Injection » 10-pin Connector Fix

Cleaning the Ford Mustang Throttle Body - Solving your idle problems

Checking, Setting and Bumping up your Mustang's Timing

Cleaning the salt and pepper shakers didnt seem to have much effect on my son's car. I suspect that his were working fine. Resetting and correcting his TPS was like night and day for that car. Felt like it picked up 15 - 20 hp. Much more crisp throttle response, idles much better and will break traction in 1st and 2nd the second you get past half throttle. Dont have to romp on it or dump the clutch at all for it to break traction.

Resetting the timing helped also. I have it at 14.5 now and it seems very happy with that. No pingning and very crisp through the RPM's.

I had an issue where the RPM's were hanging when coming to a stop from cruising and then the idle would hunt/surge up and down a little bit. I replaced a broken O2 sensor and the speedo wasnt working. I bought a new $26 sending unit. Plugged a new speedo cable in and viola. The hanging idle was gone. It needed the input from the VSS.

Your car may and will probably respond differently. You will have to go through it and hunt down what and where the problem is. All the information you need is out here on the net. I dont like hunting down all of these variables and that is why I prefer a carb over EFI. At the stock levels that both yours and my son's engines are in. A carb will more than likely NOT increase performance. Much will depend on the type of carb, tune of the carb, the intake choice and the timing settings,.. all of that will determine the final performance out put. At this level EFI and Carb are on par with each other when comparing performance. EFI gets the nod IMO because it will be more efficient and get better MPG.

The only time I will argue that a carb motor has the advantage over EFI is when very large ported after market heads, large open plane intakes and cams with a lot of duration are used. Large duration cams kill vacuum, 90% of what an EFI setup needs to be streetable comes from vacuum signals. Even a carb will need different tuning when large duration cams are used. A carb motor will tune much easier and make more power under these conditions than EFI will. I can show before and after results from 3 different motors that I have done. Carb came out the winner in all 3. Not saying EFI cant be made to work. But in the end you'll have more money invested in an EFI setup to reach the same goals.

Right now you have a working EFI set up. A carb setup on your heads and shortblock will probably not show any significant performance gains. Nothing that would make swapping worth the effort. The only worth while reason to swap would be if you have defective electronics and sensors that will cost as much or more to fix as it would to swap to a carb. Then it would make sense to swap to a carb.

Your current engine combo is not enough to need 24# or 30# yet. The 19's should be enough for now.

My son's car is only running 19's and its running a little on the rich side. Simply bumping up to 24# injectors does not make the motor any stronger or faster by themselves. The only reason would be if you were experiencing lean conditions where your 19's were hitting 100% duty cycle. I had the injectors in my son's motor professionally cleaned and bench tested before I put the motor together. If your unsure, have yours tested. You can clean them yourself. Just make sure you have some new O-rings in case your existing ones are dry rotting. You'll have a fuel leak if you put the injectors back in with dry o-rings.

Swapping to carb is a choice that should not be based on popular opinion. If you dont understand how to tune a carb set up, you will be in the exact same boat your in now if its not running right. Also realize that you'll play hell selling a carb'd car to anyone under 35 who has never owned anything except EFI.

Hope that helps.

Hurst

 

Tommy, that shit isn't enough for his head and cubic inch setup. You know that man. Those GT40x head's and the fact that it's a cammed 306, are trying to pull more air/fuel than his fuel injection system and intake can provide. You can seriously feel it.

Tommy, just ride in his car once and I can gaurentee you will say the same thing. I'll put money down his car will perform a rediculous amount better with a carb setup.

 

Jim, his injector's and fuel pump are at that level. It's running outta' fuel and it's very noticable when you're riding with him.

We picked up a set of 24lb/hr's and flow meter calibrated to them and 75mm housing yesterday. We're going to put 'em on hopefully this weekend.

I don't know much about fuel injection but I know when an engine is starving for fuel and when injector's are maxed out. Been threw it myself and had to learn the hardway.

 

Terry, just remember what you were told yesterday dude.


Tommy, you and Frank both bere witness to how slow Brett's car was with, 302-e cam-GT40x heads-roller rockers-edelbrock intake-big throttle body and mass air- and the TKO. What was the best...? LOW 13S!

Yet when Dave put those same head's on his JUNKYARD 302 SHORTBLOCK, with the e cam and roller rockers and RPM air gap and that big carb with the same TKO, what was he running...? LOW 12S ALL MOTOR AND MID-SUB 11S ON THE 150 SHOT! Gimme a break dude. And they were both GT's... And Dave had a shittier suspension and 3.55's compared to Brett's 3.73's!

All i'm saying is, when I see a combo that's slow as shit in fuel injection form (and before Jim can pop in and say there was no way it was running right, 'cause it was) then go to just a simple carb and intake setup and totally bust fucking ass I will mimick that shit because it worked!

 

With out putting a scanner on it and reading exactly what the injectors are doing, you cant say "It feels like" because no offense,.. but you dont know that for a fact. I made over 300 RWHP on a 4.6 with yellow top 19# injectors and they werent even at 85%.

He has a 240 - 250 rwhp combo. Thats it and 19# injectors are perfectly capable of handling that. His car with the combo he has should be running low 13's,. maybe some high 12's with a good tire and aggressive shifting.

Now thats not to say he doesnt have other issues causing him to run lean or out of fuel. C&L meters are notorious for giving erratic signals and just generally dont work right. I got rid of the 73mm one I had and went back to a stock housing and couldnt be happier. His pump might be faulty or the wiring to the pump could be faulty. Inline filters, clogged/dirty/defective injectors. There is a whole gambit of variables to trace down before saying the injectors are maxed out and causing the problem. I mean whats his fuel pressure reading? Is the TPS set correcly? Has the MAF been tested? How are the O2's? How is the general wiring condition and connections in the car? What condition are the vacuum lines in? So many things that NEED to be tested and checked first before you spend any money.

Do it smart. Dont guess.

Hurst

 

That's the thing... You can feel that the car want's to pull very fucking hard, it's just getting to a certain level and running out. His car need's more fuel and air. Electrical wise it's sound and good to go. His shit is setup right. And I disagree with you there on the feeling when a motor is starving, and you being from the old school should know how a car feel's when it's starving for fuel.

 

I'm all about the carb. Love it,.. cant stand EFI.
But,..

The way you guys are going about it just isnt right to me.

If his EFI has problems and is running like crap,.. then yes,.. switching to a carb will 'magically' fix the problem just by virtue of its simplicity. But,.. lets say he pops an RPM Air Gap intake and 650 Holley on there. He's still not going to make any more than 240 - 250hp and low 13's 'should' be his norm.

I ran a carb'd 306.

AFR 185 heads with mild porting at the inlets for gasket matching. Comp Pro Magnum 1.6 RR's. Comp NX274HR cam, Vic jr intake that I personally ported the shit out of to match a Felpro 1265 gasket. The heads were done the same. KB116 pistons with 2.7cc dome, just shy of 12:1cr on a basically stock 1991 .030 short block minus the pistons.

A typical run was 12.40's - 12.70's 1/4 mi @109 - 111 with 8.1 - 8.2 1/8 mi @87 - 88. Best ever ET was a 12.33@111.

His heads and intake dont flow anywhere near what I had. For his car to make a high 12 pass will need a damn good 60' and some hard aggressive shifting. And I dont know him,.. but if he's a big fat guy like me,.. forget it.

Hurst

 

How it feels with a carb,.. and being able to diagnose it is completely different than diagnosing the same problem with EFI. I just went though all of that crap with my son's car. How it feels,.. and what its doing can be two completely different things with EFI. Its not the same as diagnosing it with a carb. I just went through this learning process.

Thats one of the reasons I love a carb. There is only so much you have to figure out. Air, fuel, spark,.. thats it. The area of focus is completely simplified with a carb set up. There are too many variables with EFI that you NEED to check in order to 'correctly' diagnose a simple problem such as the motor "Feels like" it wants more fuel.

I'm not trying to be a dick. And EFI is NOT my thing,.. I DONT fully understand it. But having just gone through this very same crap with my son's car I feel I have a right to say that you guys need to stop guessing and start testing before any money is spent.

19# injectors are perfectly capable of handling his HP level. If they are defective or something in the works is defective,.. then no,.. there will be problems. Is his regulator adjustable? Have you guys even checked what his fuel pressure is at yet? Come on Jeff,.. I know its tedious. I didnt want to to it either. But it has to be done to find out where the problem is.

Either that or say fuck it and sell it all and buy a carb setup. He should come out with money in pocket. But I seriously doubt his motor will make any more HP than what it would have if the EFI was working correctly.

Hurst