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Discussion Starter #1
I have the combo listed in my signature. I have a set of 24 lb injectors in the garage, but don't know if I should swap them in. It seems like it is running fine on the stock 19 lb injectors, but I have been wondering if I could gain anything with the 24's. I have read so many times about driveability issues with 24 lb'ers. I have stock driveability now. Please advise.
 

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I was running 19s with my setup up and then switched to 24s and noticed no performance difference. But after I switched to a mass air meter calibrated for 24s my 1200 rpm surge I had been getting disappered. I originally thought it was my cam causing the surge but it wasn't.

I'd say if you got the 24s put them in and give it a try. It took me less than a hour to swap mine.
 

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Discussion Starter #3
Yeah, thing is I would have to buy a sample tube for the 24's. No big deal, but if I am going to get nothing from them, I might just sell them. I guess I could pop them in and if I don't like them I could sell the 24's with the sample tube. Thanks.
 

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they wont give you anymore power but they will lower the duty cycle of the injectors which is nice if your 19's are on the high side. it will give you better drivability and tunability.

19's will handle up to 300 hp. i dont think your there so you should be ok with 19's

take care,
adam
 

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Discussion Starter #5
avbcon12 said:
they wont give you anymore power but they will lower the duty cycle of the injectors which is nice if your 19's are on the high side. it will give you better drivability and tunability.

19's will handle up to 300 hp. i dont think your there so you should be ok with 19's

take care,
adam
300 flywheel or 300 rwhp? If you mean 300 flywheel hp, I'd say I am right there...
 

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In my opinion you don't need the 24's; your 19's are plenty. If it's running ok - if it ain't broke - don't 'fix' it. Looks like you've got yours running very respectably. See my sig - runs great on 19's. Pro-M's website (www.pro-flow.com select the meter sizing tab) suggests 19's are good for 337HP; 24's up to 426HP. The same site will also tell you how to get more flow out of your 19's by increasing fuel pressure. If the car is used for racing only and you're gonna keep modding then the swap to 24's will be needed at some point. If it's street driven and raced occasionally, you're only occasionally getting them into the higher end of the duty cycle -- if you're worried about that simply up your fuel pressure a bit when you're at the track.
 

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michael is right, BUT the numbers on pro-ms site are far from reality from what ive seen. how many people on this board are running 24# injectors with 426hp? NONE, because they just wont handle it.

take care,
adam
 

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Help us understand your 300HP estimate - looks like you've pretty much got a 93 Cobra set up with HO cam and the GT40 intake instead of a Cobra and longtubes/exhaust, pullies. The HO cam and the intake would produce very similar flows to the Cobra equipment. That would mean the exhaust and the pullies were good for 60-65HP. Seems optimistic to me - just curious what your thinking is.

As for the validity of Pro-M's numbers, I guess I'd ask Pro-M about that. They've certainly got a good reputation as an maf supplier --don't know why they'd be that far off. Just as people often over-carburate, I think they often oversize injectors. It's a guy thing - bigger is better. I switched mine back to 19's from 24's when I put my custom cam in. Glad I made the switch.
 

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Michael Yount said:
Seems optimistic to me
seems that way to me too, i hate to burst your bubble

take care,
adam
 

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Discussion Starter #10
I am talking at the flywheel. Not bursting my bubble, I just think, given my mph at the track and the car weighing 3250 without me in it (scale at Moroso), it would dyno maybe 270 rwhp. Should be pretty close to 300 at the flywheel. I don't think I could be WAY off here, maybe 10 hp.
 

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i really dont think so, im not trying to be a **** but i just dont think its correct. you have a 93 cobra motor with exhaust. your MPH and track times can be because you are a good driver. people can put stock motored fox's into the 12's, ive seen it.

take care,
adam
 

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With your combo the 19 lb injectors are probably fine. I personally am running out of fuel over 5K...so I need to upgrade my injectors. I am probably leaving 20 hp by running out of fuel. But, as previously stated, if you have the injectors it will not hurt anything to put them in. That being said, your best bet would be to dyno your car and get an air/fuel chart and determine if the 19 lb injectors are meeting your engine's demands.
 

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I'm still running 19's and we have similar combos. By the way, your Et's are due to drop significantly. Trapping 106 should put you in the 12's. Are you running street tires?
 

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I run 19# stockers on my car too and I suspect they are being pushed to their limits. (Over 300 horse) I run heads cam and intake, longtubes, blah, blah, blah, C&L 73 mm, 40 psi fuel pressure....12.50's at 108 mph all day long.

I bought my 92 coupe brand new and I have used nothing but at least 91 octane in it from day one and I have about 50,000 miles on the clock...I have also changed the fuel filter a couple of times...

I suspect that they WILL need changing soon, as they have been running at their limits for awhile now. BUT I love the drivability of the stock injectors...! I don't drive my car in the winter months as we get lots of the white stuff here. My car can sit for a month when it is freakin' cold here (-35 degrees celcius!) and I can go into the garage and it starts right now and will NOT stall and it idles perfectly even with the e303 I run...

whatever.....
 

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i ran mid 11's on stock 19#s, stock mass air, stock TB and stock intake if that helps..so they will hold for quite a bit..one of my buddies vortech car ran 24# injectors to the tune of 10.20's with a FMU
 

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.....re: my comment earlier about how I think a lot of folks go with more injector than is necessary; great examples here that 19's and 24's will support a lot more than folks think - if the car's a regular driver/occasional racer, going with the smallest injector that will support your HP level is a good idea I think.
 

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i agree with a over big fuel system is not a bad idea but the injectors i think you should run the smallest ones you can get away with
 

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Michael Yount said:
Help us understand your 300HP estimate - looks like you've pretty much got a 93 Cobra set up with HO cam and the GT40 intake instead of a Cobra and longtubes/exhaust, pullies. The HO cam and the intake would produce very similar flows to the Cobra equipment. That would mean the exhaust and the pullies were good for 60-65HP. Seems optimistic to me - just curious what your thinking is.

I dont want to start a pissing match (I've seen alot of your posts and they are full of good advise)...but he's around 300 HP, To run 105 - 106 mph with a 3250 lb car (will be around 3400 lbs with a driver) takes abot 300 to 310 hp.

Also don't forget the cobra motor was sandbaged, it puts out more than the 235 HP advertised. Also the HO cam with 1.7 rockers equates to a bigger cam than the stock cobra (more duration, about the same lift), so expect some gains there.

Tough call on the injectors, if it's running fine, stick with the 19#'rs, and just turn the pressure up at the track like someone already suggested. The money can be better spent on traction (you should be running high 12's with that mph) If the injectors fry some day, than at least you know to upgrade.......which you have contemplated anyway.
 

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Im still running 19's and have 24's to put in as well. But I posted a while ago, and decided to leave the 19's in for now as my car runs perfect with them.
 
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