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Discussion Starter · #1 ·
Sorry but im just depressed about this.

Im missing about 30 HP somewhere. I dont know if its the carb, weak valve springs, something else or a little bit of everything. The torque is reasonable but the HP started tanking at 4100 (as seen on a graph), peaked at 5500 and rolled over dead at 5800.

Engine/dyno guy said its about it for that "tiny" cam. However is see other making good numbers with it.

Consider it the joke of the day.


RPM CHP CTQ
3000 225.1 394.1
3100 230.7 390.9
3200 237.2 389.2
3300 244.3 388.8
3400 252.2 389.6
3500 260.7 391.3
3600 270.3 394.3
3700 280.5 398.2
3800 290.2 401.1
3900 299.8 403.7
4000 308.3 404.8
4100 316.1 404.9
4200 322.8 403.7
4300 327.8 400.3
4400 333.1 397.6
4500 336.9 393.2
4600 341.9 390.3
4700 345.3 385.9
4800 350.2 383.2
4900 353.4 378.8
5000 358 376
5100 360.8 371.6
5200 363.3 366.9
5300 365.5 362.2
5400 366.1 356
5500 368.7 352
5600 368.4 345.5
5700 365 336.3
5800 358.1 324.3
5900 345 307.2
6000 335 293.3


_________________
'75 Maverick 4-Door

DSS 331 SB, AFR CNC'd 165's, XE274HR, RPM Air Gap, 750 Mighty Demon, Hooker Super Comps, 2.5" Duals, MSD, 10.3:1 CR, AOD, 3.80 w/ Det. Locker, M/T ET SR

<font size=-1>[ This Message was edited by: tbirdz12 on 1/13/07 7:44am ]</font>
 

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What kind of dyno? Did you do any tuning? Timing? A/F ratio?

Was the cam degreed during the installation?

Did you get BSFC and VE numbers?
 

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Discussion Starter · #4 ·
On 2007-01-09 17:43, mstngjoe wrote:
What kind of dyno? Did you do any tuning? Timing? A/F ratio?

Was the cam degreed during the installation?

Did you get BSFC and VE numbers?
Superflow Engine dyno.
Tuned with Innovate Wideband O2 (stand alone, so no data)
Started out 15:1 then got it down to 13:1.
BTW i wasnt present at the test. Guy said these carbs like to run a little lean so he didnt richen it up more. ? Im wondering if there still is metal shavings in the carb? 15:1 sounds pretty lean to me for a stock 750 on a 331.

Cam was installed straight up, but these are ground on a 4° avdanve so essentially its 4° advanced.

You might be onto something with the BSFC. They are low where the curve starts a flatter slope at 4100.
VE # are not accurate.
There is a BSAC (#/hph) that look ok tho.

RPM CHP CTQ BSFC
3000 225.1 394.1 0.486
3100 230.7 390.9 0.481
3200 237.2 389.2 0.478
3300 244.3 388.8 0.489
3400 252.2 389.6 0.512
3500 260.7 391.3 0.538
3600 270.3 394.3 0.556
3700 280.5 398.2 0.549
3800 290.2 401.1 0.527
3900 299.8 403.7 0.49
4000 308.3 404.8 0.454
4100 316.1 404.9 0.419
4200 322.8 403.7 0.407
4300 327.8 400.3 0.405
4400 333.1 397.6 0.405
4500 336.9 393.2 0.414
4600 341.9 390.3 0.417
4700 345.3 385.9 0.427
4800 350.2 383.2 0.428
4900 353.4 378.8 0.436
5000 358 376 0.437
5100 360.8 371.6 0.442
5200 363.3 366.9 0.448
5300 365.5 362.2 0.451
5400 366.1 356 0.459
5500 368.7 352 0.461
5600 368.4 345.5 0.468
5700 365 336.3 0.475
5800 358.1 324.3 0.486
5900 345 307.2 0.505
6000 335 293.3 0.522
 

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Personally, I thinks that's a bit lean. I'd like to see something around 12.5-12.8 at peak power. And the bottom at 15:1 seems quite lean to me.

That cam isn't "tiny" in a 331. But, it's slightly bigger than what AFR recommends for the standard springs on the AFR 165.

It's hard to tell without the dyno graph, but I suspect you may be having some valve float.

You didn't mention what the timing was. Also a possibility.

The BSFC looks suspiciously good. What jets are in the carb now?

Any EGT reading for the dyno session?

The cam may be "installed straight up", but it still should have been degreed to elimate the cam as a problem.

Keep in mind that there are different things that effect dyno numbers. Not limited to just correction factors, but also the competence of the operator and whether or not the dyno is properly calibrated and data input is valid.

BTW, what was the correction factor on those numbers?
 

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Definitely correct the cam issue first, running advanced is not going to help your top end.
Agree with the little lean comment as well...... plus the timing??
 

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I'm going to go out on a limb here, and fly in the face of what's been said in a few points.

I think the cam is too small. I think the 165cc head is too small. These 'are' personal opinions, and you should still get a bit better rpm out of it than that...but don't expect too very much.

I will also say...installing a cam 'straight up' means very, very little. Do you mean dot to dot? If so, go back and degree it. I wish timing chains came with NO DOTS. Those little dots cause more problems that people aren't aware of than is even possible to go into in a post. If you don't mean dot to dot, please explain which 'straight up' method you used. Hopefully it involved a degree wheel =). If not...do it again!

Other than my difference in opinion on the heads and cam, these guys will lead you on the right path to figuring why your numbers are a bit down. But just for the sake of you knowing...with your compression, bigger heads, and a good hydro or even better...solid roller cam...you could easily have 500hp on your hands out of that 331. 450hp without breaking a sweat.

I know, I've done it =).

Cris

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If you can't beat 'em...you must not drive a Ford!!




<font size=-1>[ This Message was edited by: Is1BadFord on 1/11/07 7:22am ]</font>
 

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Discussion Starter · #8 ·
Thanks for the replys.
The cam was degreed and installed at the recommended 108 cl. Cam is 224/232 .555/.565 @50 112 CL.

I dont know what the correction factor was. All i got was one sheet with the corrected numbers on it. Im gonna ask for the uncorrected info.
The test sessions was not with the Super comps, but some other 1 5/8in headers.
No EGT info

Im really not impressed with the data or info im getting from the engine builder. There was no timing tab on the engine so he cant tell me what the timing ended up at. Ill have to check it when it put a timing tab on it.

I will reverify the cam installation (degree) and possible retard it some.

The valve springs are too weak i think. 130 seat/326 open.

I think that with the cam setting will account for it dying around 5500?

To clarify the lean condition. IT was 15:1 A/F on the first pull, then he jetted up to ? jets and ended up at 13:1 on the 6th pull. I am suspicious of the carb having junk shavings in it. I will go thru it to verify.

_________________
'75 Maverick 4-Door

DSS 331 SB, AFR CNC'd 165's, XE274HR, RPM Air Gap, 750 Mighty Demon, Hooker Super Comps, 2.5" Duals, MSD, 10.3:1 CR, AOD, 3.80 w/ Det. Locker, M/T ET SR

<font size=-1>[ This Message was edited by: tbirdz12 on 1/11/07 6:04pm ]</font>
 

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Do you know what jetting you have in your carb now? Are you also sure the throttle is opening 100%?? Maybe your gas pedel is not reaching long enough to pull you open 100% on both front and rear??? Also the throttle plates may only open 90% on the rears, from a mechanical stop??

Whatever it comes with.... you should have at least 74 Primary jets and 82 - 84 secondary jets. 6.5 power valve and as bought air bleed jettings....

You should be making peak tourque at 5200, could also be a timing thing... the dyno guy should have at least did your timing for you... total timing should be between 32 - 36 at 3000 RPM's. Gas would not matter too much for the power curve peaks you have....

You should be making power into the 6000 rpm range


If your jetting is close to what I stated and your going to take your carb apart, ask and I will tell you all the places to look for the machining junk.... One key item, the main body to throttle plate gasket is not a standard Holley gasket like all the others... it is slimmer between venturies, and has a different place for the idle hole.
 

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There was no timing tab on the engine so he cant tell me what the timing ended up at.
I wouldn't use this guy again.

And I'd pretty much not trust any dyno numbers he gave you.

What's the name of the shop? Where exactly are you located?

As to your combination, I would have done things a bit different myself, but it is what it is at this point.

You may have some more power there, but things need to be sorted out to know exactly how much you're missing.

Yes, bigger heads would make a difference. Yes, another cam would make more power. But dialing in your current combo is the question at hand. Once you've optimized what you have now, you can decide if it's right for you or not.
 

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On 2007-01-11 08:45, mstngjoe wrote:
There was no timing tab on the engine so he cant tell me what the timing ended up at.
I wouldn't use this guy again.

And I'd pretty much not trust any dyno numbers he gave you.

What's the name of the shop? Where exactly are you located?

As to your combination, I would have done things a bit different myself, but it is what it is at this point.

You may have some more power there, but things need to be sorted out to know exactly how much you're missing.

Yes, bigger heads would make a difference. Yes, another cam would make more power. But dialing in your current combo is the question at hand. Once you've optimized what you have now, you can decide if it's right for you or not.
+1!

I was just pointing out that he shouldn't get his hopes too high with the combo he has. Dialing it in as/is would be, of course, paramount.
 

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On 2007-01-11 10:04, Is1BadFord wrote:

+1!

I was just pointing out that he shouldn't get his hopes too high with the combo he has. Dialing it in as/is would be, of course, paramount.
No....I agree Cris.

This combination may have a bit more to be found, but not lots.

Tough to say how much......I'd wouldn't really like to guess based on the dyno info given so far.
 

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I have to agree with everyone else that something in that I have an issue the dyno operator not being on top of timing, etc.

So, while there may be more left in tuning, considering your combo, I don't believe that the powerband is all that far off. As stated, you need more head flow and more cam to carry your torque curve into the higher rpms.
 

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No, it's not totally unreasonable.

We've already concluded that there may very well be some tuning issues, but even then, your goal is at the high end of your combos limits.
 

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Discussion Starter · #16 ·

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Tuning... he should still be increasing power above 5500 rpms with that combo..... Tourque gone at low 4000s....? Not enough gas or timing is wrong..... Even the HP slope changes at 4000.

Gas supply is not up to snuff? Have a good High flow filter? Anything under $15.00 are for lawnmowers. 3/8 line? Electric or mechanical?

Any word on if you know your throttle plates are fully open? A good cleaning of that carb may find one main channel is partly blocked. The power slope projected, is about 1/4 lower then it should be after 4000. rpms.
 

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The tuner I use has a Superflow chassis dyno, so I'm a little familiar with the Winpep software.

I have no idea what scale the guy is using for the a/f ratio or the VE%.

Here's some BSFC info:

http://www.westechperformance.com/bsfc.htm

Most of the engine dynos I know of use 8 EGT probes. One in each exhaust tube close to the head. That's how they tune the fuel. If your guy doesn't use the EGT then he's most likely using a wideband O2 of some kind.

I don't know anything about the McQuillen shop other than what's on their website:

http://www.mcquillenengines.com/index.html

...and what you've told us here.

But if you paid these guys to build your engine and dyno it, they shouldn't have a problem explaining things to you. Such as why you don't have a timing tab and why they can't tell you what the timing is.

Look at some of the other dyno sheets here on FM and you'll see the type of numbers that are typical for A/F ratio and VE%.
 

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Discussion Starter · #19 ·
On 2007-01-13 04:36, Mikes66 wrote:
Tuning... he should still be increasing power above 5500 rpms with that combo..... Tourque gone at low 4000s....? Not enough gas or timing is wrong..... Even the HP slope changes at 4000.

Gas supply is not up to snuff? Have a good High flow filter? Anything under $15.00 are for lawnmowers. 3/8 line? Electric or mechanical?

Any word on if you know your throttle plates are fully open? A good cleaning of that carb may find one main channel is partly blocked. The power slope projected, is about 1/4 lower then it should be after 4000. rpms.
Thank you Thank you Thank you.
It only gained 10 hp beyond 5000. Not right. All looks fine below 4100, then it dies.
Im in the middle of a garage makeover so the engine is on the back burner at the moment. When i get a chance, i will check the thottle plate WOT position, tear the carb apart, check the jetting and check for debris. Im also going to get some beehives to lighten up the valvetrain and float problem.
Im am not impressed with the service i got out of this shop. The data i got back is mostly useless. No oil temp, water temp, A/F ratio, timing, jetting and much more.

Thanks for all the replies, suggestions and ideas. I will keep you posted on anything i find.

tim
 

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Did he have an air flow device on it. The SCFM is way to low, which affects the VE% and A/F ratio. looks like it was not even hooked up. If so WAY out of calibration.

<font size=-1>[ This Message was edited by: tmeyer on 1/14/07 4:05am ]</font>
 
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