Mid Ohio in April

[jim1548534743]

Going over the car (89 bird) with 1998-2002 front brakes and 1/2" wheel spacers there is still fender/wheel rub at the bottom of the fender and tire. Using the stock GTA wheels I loose no less than 25% of turning radius because of the rub. The stock A-arms are on the car as is the cross member (appears to be) Any ideas whats going on, how has anyone solved this problem? How was the car driven before is my question.

[Den341548534727]

Jim Check your private messages and give me a call sometime. I know a lot of history on your car and can help you out with some of your questions.

[Tom P]

I'm out! Super disappointing dyno run yesterday.

 

 

Specs: Stock 5.0L H.O. short block, GT40 heads, Cobra intake, 65mm throttle body, unequal length headers, 19 lb injectors, GT ECU.

 

Also: New fuel pump, filter and lines. Original fuel pressure regulator. timing set at 12 degrees. Fuel pressure (on my aftermarket gauge) read 36. The pressure spec is 37-38.

 

Notes: Motor runs smooth. Indoors, the car smells like it's running rich though an air / fuel exhaust probe measured it super lean with the ratio over 17. The operator said we were lucky it didn't blow a hole in the pistons because it was so lean. Said the smell is unburned hydro-carbons.

 

In conclusion: I don't know if the lean condition is responsible for a 30 rwhp drop from what I was projecting or if the motor is just "worn out". The last time it was dyno'd was a couple of years ago before the heads, headers and fuel system revisions and it was 235 rwhp. Not very many miles since.

[Adam Ginsberg]

Tom, a few suggestions:

 

• 1. The 19lb injectors are not enough. Use a

BSFC/injector sizing calculator to see what I'm talking about. 8 injectors, BSCF of .50, duty cycle of .80, estimated HP of 300 (flywheel, not RWHP), and you'll get 23.4lb/hr injectors. The 19's won't cut it.
 
2. Stock 5.0L engines have the piston a bit in the hole (can't recall how much). The valve reliefs + depth of pistons in the hole + larger chamber size of the GT40 irons = LOWER compression, hurting your ability to make the numbers. Did you have the heads CC'd? If the motor is coming apart again, shave the heads to raise the compression. Get as close to the 10:1 allowance as feasibly possible. Check the items listed above that can effect compression. You might be able to simply remove the heads, check the piston depth, shave the heads (be sure to have them CC'd), and reassemble without having to redo the shortblock. It's been done before.
 
3. You didn't mention the cam. Are you running an E-cam? Roller rockers? I don't think you'll make the numbers with a factory 5.0L HO cam.
 
4. FPR - you mention "original FPR". Not adjustable? An AFPR is very helpful.

 

It's unfortunate you didn't get the numbers you were looking for.

[CMC#11]

I have heard discussions about the 19lb injectors and know the math behind it not being ideal to make 260 hp.

I'm not going to argue w/ science but the injector size is not your big problem. I have run the same 19 lb injectors for over 6 years, the last 2 1/2 being in CMC2 trim and have been at 260hp the entire time. It might not be perfectly ideal but it can be done.

 

Not running an aftermarket FPR and having that fuel pressure and A/F ratio you mentioned is a big problem on your numbers. You need to have adjustability of your fuel. I think my fuel pressure is at 42 lbs.

 

Also, as Adam mentioned, the cam is going to be a huge factor. When I ran the old CMC at 230 hp I had the GT40 heads and all other Cobra parts and was at 230 hp. When I went to CMC2, all I did was install the e-cam (even kept the stock exh manifolds), and was right at 260hp.

 

Thankfully, a FPR and cam can be done for a few hundred bucks. I'd at least throw a FPR on it, adjust your fuel pressure up and go shake it down on the track.

[ShadowBolt]

Tom, a few suggestions:

 

• 1. The 19lb injectors are not enough. Use a

BSFC/injector sizing calculator to see what I'm talking about. 8 injectors, BSCF of .50, duty cycle of .80, estimated HP of 300 (flywheel, not RWHP), and you'll get 23.4lb/hr injectors. The 19's won't cut it.
 
2. Stock 5.0L engines have the piston a bit in the hole (can't recall how much). The valve reliefs + depth of pistons in the hole + larger chamber size of the GT40 irons = LOWER compression, hurting your ability to make the numbers. Did you have the heads CC'd? If the motor is coming apart again, shave the heads to raise the compression. Get as close to the 10:1 allowance as feasibly possible. Check the items listed above that can effect compression. You might be able to simply remove the heads, check the piston depth, shave the heads (be sure to have them CC'd), and reassemble without having to redo the shortblock. It's been done before.
 
3. You didn't mention the cam. Are you running an E-cam? Roller rockers? I don't think you'll make the numbers with a factory 5.0L HO cam.
 
4. FPR - you mention "original FPR". Not adjustable? An AFPR is very helpful.

 

It's unfortunate you didn't get the numbers you were looking for.

 

Adam,

 

My 4.6 makes close to the numbers with the 19lb. injectors (255/299, 262/292 last two years). I agree with making sure the heads are cc'd but I would guess the 17 A/F ratio is why he is down so much. My first car (Varner's 17) had the strong fuel smell and ran so rich the headers would glow. I was still way under the numbers after rebuilding until I replaced the MAF and got the A/F right then I got as close as most other 302's do.

 

JJ

[Tom P]

Thanks guys for your input. Since this could get way off topic, I'll just put in my $.02 and drop it. If there is interest I can always start another thread just on this.

 

1. Agreed. Adjustable regulator looks mandatory at this stage. Mine is the original OEM. Maybe even a higher flow pump to make sure the pressure can get to 40-45psi. but I haven't read if that's legal yet.

 

2. I've read too many articles on owners achieving 15-20 hp just by bolting on GT 40 heads with 19 lb injectors. Mine produced 235 before and I was looking conservatively at +10-15. I would have been happy @245 HP. But instead of gaining 20, I lost 20 so something is amiss more than injector size.

 

3. I run the 1.7 Cobra roller rockers. This is my third 5.0L combo and never had results this low. I've also had the E cam before. Even the old E5 heads with 69MM chambers made 229. Chamber size on the GT40s is approx the same as stock E7s. GTP's run about 3.5 ccs smaller.

http://www.carbdford.com/tech/flowdata.htm

 

4. Bottom line, and my main interest is, can a drop in fuel pressure a few pounds and a lean condition like I had produce a 30 HP loss? I have no idea.

 

So if the compression checks are okay then probably something dealing with the EFI and it could be difficult to find the cause without a lot of part swapping, guesswork, wasted dollars, etc. It could be anything from a vacuum leak, O2 sensors, fuel pressure, ignition, bad gas from the winter, too much Stabil. It's anybody's guess. Wish it had OBDII.

 

My problem is determining root cause before spending more to fix it than the whole car is worth. I know I could eat up a good portion of it's worth on dyno time alone!

 

Thanks for the suggestions.

[cozog1548534733]

Mine produced 235 before and I was looking conservatively at +10-15. I would have been happy @245 HP. But instead of gaining 20, I lost 20 so something is amiss more than injector size.

NVM

[cozog1548534733]

Entry list updated on page 1...

[DrC]

Odd, I am having the same problem with the motor running lean. New motor with the E-cam, 1.7 rockers and GT40P heads.

[DrC]

I just checked the Temp off the headers and found something. As you can see the 3 and 4 cylinders are running a lot hotter so this weekend I am going to check out the injectors to see if that could be my problem.

FYI My fuel pressure is at 40 psi, may jump it up to 45psi.

 

1 – 360f

2 – 408

3 – 560

4 – 610

5 – 330

6 – 440

7 – 358

8 - 370

[MHISSTC]

Tom,

 

Don't give up on your current setup yet.

Several things came to mind reading the previous posts along with a few suggestions:

 

1. An overwhelming smell of un-burned hydrocarbons would indicate a rich condition, not a lean condition.

 

2. I may have missed it, but I'm assuming since an E-cam was mentioned that your car is a MAF EFI and not a Speed Density EFI. Is that correct?

 

3. Get an adjustable fuel pressure regulator and bump that pressure up to about 44 psi.

 

4. Have your injectors been flow-checked, cleaned and reconditioned? Because we are cheap and didn't want to buy new injectors "just in case", when we had our engine rebuilt several years ago, we sent 16 used 19lb injectors off to Marren (www.injector.com) with specific instructions to test, clean, and flow match 8 injectors. They went through 9 before they found 8 good ones and one bad one. They sent back all 16 with little printouts of the testing specs on each one they checked out and reconditioned. That doesn't mean one won't fail tomorrow, but it went a long way to inspire confidence that the injectors weren't going to be an issue.

 

5. It is totally possible to make the numbers with 19 lb injectors. At OEM fuel pressure you will be running the injectors at a very high duty cycle very close to or right up to 100% (I forget the exact numbers) to make the CMC numbers, if you can reach them at all. A higher fuel pressure will compensate for the smaller injectors somewhat and allow them to spray more fuel and run at a slightly lower duty cycle.

 

6. We are currently making the numbers (261 rwhp, 299 rwtq) with an engine that is basically a '93 Cobra Engine bored to 306 with an '88 (I think that's the correct year) manual transmission speed density computer running 19lb. injectors and 44 psi fuel pressure, OEM cam, 14 deg. timing, a set of underdrive pulleys, and a set of Ford Racing ceramic coated unequal length headers flowing through a dual exhaust with an X-pipe and no mufflers or cats. We are also using the stock '86 intake tube with a K&N filter in the stock airbox. We found the stock airbox made more HP than an open element filter.

[wastntim]

10 cars registered without at least 2 regulars, 15 is a stone's throw. If we could get some non-region cars for Nats, we could be @ 20+ cars.

[Tom P]

Scott.

I sent you a PM.

[MHISSTC]

Tom,

 

I sent you an email.

 

Scott

[Adam Ginsberg]

My comment regarding the 19lb injectors "not cutting it" was referring to the significant duty cycle it puts on them. Running injectors at or very near 100% DC is not good - they will flutter, and can fail much quicker. That can lead to a lean cylinder.....and we all know what happens when a cylinder goes lean.

 

I prefer to have more of a "cushion", if you will.

[Mike D1548534719]

Make sure your getting full timing advance from the ECU, Some times the timing connecter shorting bar can go open, this is good for 30 or so horse power.

 

Mike D

[bluebandit48]

Im sorry for not touching base sooner.. I did not get my air fuel raito measured when i went to the dyno but I made exactly what i was expecting to make. 264, 298. That was with the Cobra heads, 94 cobra intake, Cobra injectors, BBK equal length headers, stock intake tube, E303 cam, a little bit stiffer valve spring, and that’s about it. I did find this weekend a fuel starve problem. I run a fuel cell, and my 255 warbro fuel pump could not keep up at high RPM. This problem was fine in the rain, which is why I still managed to qualify second, and run second until a sudden loss of talent moved me back a few spots. I actually had to end the day early on Sunday because of how bad this problem was. I talked to a few people to find that my fuel pump (in line) is a pusher, not a puller, so to “correct†this I will be adding another fuel pump to my system (holley blue). I was told this has more than enough volume to pull the fuel out of the cell and not create this problem and actually fix it. SO, this was my lean issue and I believe that I have solved it. But I will have to wait and see until the next track day.

[doug1548534725]

Is your current pump mounted up front near the engine? You might be able to move the pump you have to the rear near the cell and mount it at the proper elevation (below the level of the cell) and be fine without buying another pump. You want a siphon/gravity feed effect coming in to the pump.

 

Your wording makes it sounds like you are planning to run 2 fuel pumps inline, which should be unnecessary.

[Glenn]

A Walbro 255 is an "in tank" pump. All in tank pumps need to be submerged in fuel in order to stay cool. If they are not, they will burn up.

[bluebandit48]

http://treperformance.com/i-133255-universal-inline-walbro-255-lph-fuel-pump.html

 

it is an in line non internal pump. it is at the back of the car, by the fuel cell. there is probably only 1 foot of hose from the tank to the pump. I already have a holley fuel pump laying around, and I was told that he had the same problem, and this is what he did to solve it. So I figured it was worth a shot.

[doug1548534725]

1 foot isn't really enough for the pump to be as low as it needs to be. If the pump has to suck the fuel up out of the cell, it's going to work very hard, and won't meet the published specs.

[Al F.]

You should definitely not need a second pump. Something is wrong. Either you're not getting enough flow to the pump, or your line/filter is restricted downstream of the pump, not getting good voltage, or pump itself is bad. That pump on its own is more than sufficient if everything is working right.

[bluebandit48]

I don't know. I have good voltage. Its a brand new pump. And I took off all of the filters just to see if that's what it was.

[doug1548534725]

I was having similar problems not too long ago on my Camaro. It was sputtering and struggling at high RPM like it was getting starved for fuel. I replaced the pump, removed the filter, did all the volume tests I could think of, and it all checked out fine. Under yellow/rain conditions it wasn't nearly as bad because it was cooler and I wasn't on it as hard. I thought the same thing you did: this translated to lesser fuel consumption.

 

Ended up being an ignition-related problem. I replaced my distributor, plugs, and wires, so I'm not sure exactly which one it was, but I think some of my plug wires had finally melted a little too much and couldn't keep up spark when the going got tough (and hot).