422 dyno fail

-
In regards to "strokers and eating up duration..." ..for the reader..It's really called the bigger the cid.. the bigger the power and more forgiving the low end losses are if not helpful to keep the tires sticking in a low weight car from a larger cam.
Plain and simple there plenty enough spare.


If the heads are **** in the sub .500 left it's going to be a turd. Period.
A head that's fat through .500 '20 cfm better than stock every lift' and falls off 15-20 cfm after .500 will still make a ton more power than one that flows like stock but holds to make a higher peak @.600, I dont care what anyone says.. go dyno it and see.

The heads suck.
 
@PRH That was an interesting speil on BSFC.
My W2 engine only mad 494 HP and 484 ft-lbs with a 246/250 @ .050 on a 108 even though the heads flowed 297 @ .650 lift . The BSFC #s struggled to hit the 4s at any point . The motor only wanted around 32 degrees total so I thought it would be more efficient and get lower BSFC #s.
 
I thought after you had your motor off the dyno you discovered something that was the likely cause of the lower than expected power?

The top end of the run on the last sheet from the OP had the bsfc numbers in the .7 range.
In 32 years, I don’t think I’ve ever seen them that bad....... not without a plug wire off or something like that.

Poor bsfc numbers are simply the result of using a lot of fuel....... and not efficiently converting it to hp.

Edit- just read thru mbairds old dyno thread.
His engine was overfilled with oil by 2.75qts....... which I have personally seen cause big power losses.
 
Last edited:
PRH said:
I thought after you had your motor off the dyno you discovered something that was the likely cause of the lower than expected power?

The top end of the run on the last sheet from the OP had the bsfc numbers in the .7 range.
In 32 years, I don’t think I’ve ever seen them that bad....... not without a plug wire off or something like that.

Poor bsfc numbers are simply the result of using a lot of fuel....... and not efficiently converting it to hp.
Click to expand...
We did a dyno test of a BB Mopar years ago, trying to push limits of the NEW beehive springs...after a 15 min. convo with Billy Godbold at Comp, we tried some solid FT lobes with the beehives...during break in...2500rpm the bsfc's were way out to lunch...so we pulled the intake off and the lobes were all going bye bye.
Changed springs, new cam (same specs and lobe family), during break in bsfc's were normal...break in was successful! Added the inner springs and away we went. After looking at our data, and the materials, Comp said the lifters were not staying in contact with the lobes...yeeeeah.

Most of our sb mopars with ported heads (not factory heads mind you) will have BSFC's in the .400 to .450 range with DP intakes and 750-950 carbs.
Our race stuff will see the BSFC's in the .385-.400 range.
The BB we tested, once tuned at WOT made BSFC's in the .440 range.
 
I don’t get very worked up about less than stellar bsfc numbers if the tq/hp are in line with expectations.

For example, if the build should be 500/500, and it’s in that range....... but the bsfc numbers are on the high side, it’s just an indication that it took a more than “optimal” amount of fuel to get the job done.

I’m not going to spend much time chasing that down when the power is as expected.

That being said...... bsfc numbers in the .6 and higher range are FAR from “less than stellar”.
 
PRH said:
I thought after you had your motor off the dyno you discovered something that was the likely cause of the lower than expected power?

The top end of the run on the last sheet from the OP had the bsfc numbers in the .7 range.
In 32 years, I don’t think I’ve ever seen them that bad....... not without a plug wire off or something like that.

Poor bsfc numbers are simply the result of using a lot of fuel....... and not efficiently converting it to hp.

Edit- just read thru mbairds old dyno thread.
His engine was overfilled with oil by 2.75qts....... which I have personally seen cause big power losses.
Click to expand...

Yes it was overfilled and I cleaned up the Victor intake but without dynoing it again I hate to speculate what it may be putting out now.
Still surprised at the high BSFC numbers . My heads are the closed chamber race heads and CC/polished with .040 quench. I would have guessed it would be more efficient .
 
I don’t think you fully understand the bsfc numbers.

If you had a motor making 500hp uncorrected, and it was using 250lbs/hr....... the bsfc would be .50.

If you added 3qts of oil to it and it lost 50hp...... it would still use the same amount of fuel....... but the bsfc for 450hp and 250lbs/hr would become .555

Any power you lost from the extra oil in the pan hurts the bsfc number.
The more it lost, the more it affected the bsfc.
 
PRH said:
I don’t think you fully understand the bsfc numbers.

If you had a motor making 500hp uncorrected, and it was using 250lbs/hr....... the bsfc would be .50.

If you added 3qts of oil to it and it lost 50hp...... it would still use the same amount of fuel....... but the bsfc for 450hp and 250lbs/hr would become .555

Any power you lost from the extra oil in the pan hurts the bsfc number.
The more it lost, the more it affected the bsfc.
Click to expand...

Thanks for the clarification . That makes sense. I do understand that parasitic drag would raise it but forgot about the oil windage effects .
 
The only way the bsfc numbers from your dyno session are correct is........ if the extra 2.75qts of oil didn’t have any impact on the HP.
 
B3,
Post 167. That is exactly I said in post #$163: reduce duration if you want a smoother idle.
To others: all else being equal, tighter LSA creates less idle vacuum & rougher idle.
As cu in increase, the engine sees the cam as being smaller.
 
Bewy said:
B3,
Post 167. That is exactly I said in post #$163: reduce duration if you want a smoother idle.
To others: all else being equal, tighter LSA creates less idle vacuum & rougher idle.
As cu in increase, the engine sees the cam as being smaller.
Click to expand...

the hot Rod test I posted used the same duration on each LSA cam.
Of course decreasing duration will smooth out any cam, but decreasing a given cam’s LSA won’t. Narrower will be choppier
You didn’t seem to agree with that earlier.
 
I never made any mention of 'choppier'. Because it means nothing unless it is referenced to something. I think is the first time you mentioned choppier in this thread, so how I could 'agree' with it earlier? Are you referring to idle quality? If you are, then you just torpedoed your own argument. If not about idle quality, what then?
 
“ If you want a smoother idle, you do not widen LSA”

the above is what you said. It’s dead wrong, that’s my point.
You can muddy the waters all you want.
 
SixPaksRule said:
just another over cammed stroker engine
Click to expand...

YOu think 240@.050, .570, 110LSa on a 422ci engine is over cammed? Well, you're dead wrong.

================
B3422w5 said:
“ If you want a smoother idle, you do not widen LSA”

the above is what you said. It’s dead wrong, that’s my point.
You can muddy the waters all you want.
Click to expand...

While it may not be the only way, it is A way to smooth idle. I'd love to read his response as to why LSA doesn't improve idle quality. Dude should definitely work for Mopar R&D because they have obviously gotten this wrong for years,
 
Last edited:
roccodart440 said:
YOu think 240@.050, .570, 110LSa on a 422ci engine is over cammed? Well, you're dead wrong.

================


While it may not be the only way, it is A way to smooth idle. I'd love to read his response as to why LSA doesn't improve idle quality. Dude should definitely work for Mopar R&D because they have obviously gotten this wrong for years,
Click to expand...

yep. You take 3 cams, all of which are say 260@50…one is on a 106, one on a 110, one on a 114 LSA, the 106 will have the worst idle quality, by nature.
 
B3422w5 said:
yep. You take 3 cams, all of which are say 260@50…one is on a 106, one on a 110, one on a 114 LSA, the 106 will have the worst idle quality, by nature.
Click to expand...

Funny thing, an engine builder here, who apparently knows nothing, sent me a custom grind roller (260@.050, .650, 112LSA) Wonder why he did that?? Definitely wasn't to improve my idle quality, octane requirement and street manners....
 
roccodart440 said:
Funny thing, an engine builder here, who apparently knows nothing, sent me a custom grind roller (260@.050, .650, 112LSA) Wonder why he did that?? Definitely wasn't to improve my idle quality, octane requirement and street manners....
Click to expand...

yes, his selection will indeed improve idle quality. On most “ head limited” typical Mopar bracket combo’s I have found narrower to go down the track faster. That said, higher LSA likes more compression and convertor to get it to leave.
I swapped out a 107 cam( Dwayne did for me) for a 112 cam a cam guru who knew me and my combo and said my car would be faster. Knocked about 1.5 tenths out of it, killing my 60 foot. This was an 11.5 compression flat tappet W5 deal at the time.
You will most often( at the track) see wide stuff on power adder combo’s or stuff like pro stocks..which have tons of compression and great heads, or stuff with lots of inches good heads, and compression
 
B3,
Post #188. Yes I did say that but you also left out the rest of the quote, which was from DV.
You are the one muddying the waters. Widening the LSA will smooth the idle, but to retain max power, the correct method to get a smoother idle is keep the computed LSA & reduce duration. This is the gist of my original post, a quote from DV.
 
Smoother idle and hot rod are two words I've never used in the same sentence for a NA build. Some folks need to take up golf.
 
I didn’t see where the OP made any mention of his concerns about idle quality...... but maybe I missed it.

My guess is....... if his motor was making solidly over 1hp/ci....... and idled a little rough in doing so...... he’d be okay with that.
 
Boy, this thread sure went sideways. @Jim Ward what did you learn from all of this? I hope that some of it helped. My 2 cents would be to make any checks outside of the car before installing it. Things like checking cam degree, spark plugs to check for dead cylinders, double check TDC compared to your damper, double check valve lash, perhaps even check the springs that are installed and consider upgrading them if they are not up to the task. I personally would not worry about the cam, (except checking the degree), the headers, the heads for flow. Perhaps others can make some constructive recommendations for how to proceed without starting over.
 
It’s kinda funny.......

If the dyno sheet said 600hp with the bsfc numbers in the mid-3’s...... everyone would know the dyno data was just flat out wrong.

But since the numbers are pretty low, people assume the dyno is correct and the combo is soft.

I’m still not convinced the dyno data is correct.
 
Kent,
Thank you I have already decided to take the entire engine to the shop that did my heads. The shop who built the motor I would never say anything bad about I just do not believe he thinks there is anything wrong and the numbers are the numbers. I disagree based on what I believe this combo should make. I just feel there is something wrong. If the curve looked good with nothing jumping out at me and the numbers where what they are then so be it but I feel the erratic HP vs RPM curve is telling me something. Just have to figure out what it’s telling me. I would rather get the problem fixed now and save a catastrophic failure than throw it in. I’m trying to get my 72 and 71 dusters ready for the nationals. Not certain the 71 will make it unfortunately.

Jim
 
Jim Ward said:
Kent,
Thank you I have already decided to take the entire engine to the shop that did my heads. The shop who built the motor I would never say anything bad about I just do not believe he thinks there is anything wrong and the numbers are the numbers. I disagree based on what I believe this combo should make. I just feel there is something wrong. If the curve looked good with nothing jumping out at me and the numbers where what they are then so be it but I feel the erratic HP vs RPM curve is telling me something. Just have to figure out what it’s telling me. I would rather get the problem fixed now and save a catastrophic failure than throw it in. I’m trying to get my 72 and 71 dusters ready for the nationals. Not certain the 71 will make it unfortunately.

Jim
Click to expand...

you taking it to Jack?
 
You must log in or register to reply here.
-

Back
Top