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dyno results... not happy diagnosis please

Posted By: MikeyT

dyno results... not happy diagnosis please - 08/26/11 05:11 AM

Hi guys

I was excited last week took the car to the dyno to see what result happened from my changes to the car.

Ok here is car last year
4040 with me in it
440 40 over 9.5:1 compression ratio
440stealth heads
comp cam XE 268 degreed to 107 LSA
770 street avenger carb
street dominator intake
shorty style headers
727 2600 stall converter
3:23 gears
uncapped headers thru 2.5 inch cutouts

HP 327
Torque 404

Ok tonight

4040 with me in it
440 40 over 9.5:1 compression ratio
440stealth heads
comp cam XE 274 put in straight up at 110 LSa
750 Holley Double pumper 76/78
street dominator intake
shorty style headers
727 4200 stall converter
3:91 gears
uncapped headers thru 2.5 inch cutouts

HP 311
Torque 334!

ok, I'm down 16 HP and 70 lb of torque!

It doesn't make sense!

The car runs beautifully, pulls strong now all the way up to 5800 rpms! It is a blast to drive. It comes out of the hole like its on fire now.

Why would I be down?

Thanks for any info

Ok for the record temp and humidity for pretty similar!

Take it away fella's

Mike
Posted By: 8urvette

Re: dyno results... not happy diagnosis please - 08/26/11 05:23 AM

did u get any afr's?
Posted By: MR_P_BODY

Re: dyno results... not happy diagnosis please - 08/26/11 05:29 AM

What changes did you make while still on the dyno
to get it to pick up
Posted By: MikeyT

Re: dyno results... not happy diagnosis please - 08/26/11 05:50 AM

Afr's were good most of pull around 12.5 and at about 5600 started to richen up a bit.

Things I did, were jet it up, up front to 76 and backed off a bit in back 78 jets, which was a 2 jet sized up and one down in back

Timing was 36 all in At 3000 rpms

Mike
Posted By: MR_P_BODY

Re: dyno results... not happy diagnosis please - 08/26/11 06:11 AM

Quote:

Afr's were good most of pull around 12.5 and at about 5600 started to richen up a bit.

Things I did, were jet it up, up front to 76 and backed off a bit in back 78 jets, which was a 2 jet sized up and one down in back

Timing was 36 all in At 3000 rpms

Mike



Check your fuel supply that its doing proper(flow
test)... start a process of eliminations to what is
holding it back... simple things first... testing
can be fun... dont let it get you down
Posted By: goldmember

Re: dyno results... not happy diagnosis please - 08/26/11 06:20 AM

Loose torque converters on chassis dyno's often lead to results that don't match actual performance. A manual trans would help make the playing field more level. I assume this is the same dyno used in the previous testing? What info was the dyno operator able to give about the results?
Posted By: Cab_Burge

Re: dyno results... not happy diagnosis please - 08/26/11 06:20 AM

Did you verify that the new carb is all the way open when the gas pedal is on the floor? Simple stuff first, then look at the tune up One other thing is "Street Avavenger 770" CFM carb versus "Holley 750" CFM D.P. carb Do you still have access to the other carb If so try it next
Posted By: topfueldart

Re: dyno results... not happy diagnosis please - 08/26/11 06:24 AM

Firstly... Bigger converters tend to soften number on wheel dynos. Lots of times cars with big converters give off weaker numbers, especially if they have a hard time calibrating the load correctly. Where was peak torque RPM wise both times?
Posted By: Charger VJ RB

Re: dyno results... not happy diagnosis please - 08/26/11 09:18 AM

Don't worry about the dynos especially chassis ones they are just a tuning device for the track, run it and see what time it makes then you will know actual HP.
Posted By: MikeyT

Re: dyno results... not happy diagnosis please - 08/26/11 11:18 AM

Thanks guys! These are great ideas. To answer the question.

Torque wise it looked like converter came in at 4200 peak!

Cab great idea. I'm pretty sure it was opening all the way, but I'll check it. I do have access to the old 770 street avenger carb.

Thanks for the support. I'll look into these things and get back to you.

Mike
Posted By: ultimatelenny

Re: dyno results... not happy diagnosis please - 08/26/11 12:57 PM

Quote:

Don't worry about the dynos especially chassis ones they are just a tuning device for the track, run it and see what time it makes then you will know actual HP.



X2 Get your tune up close on the dyno then get to the track and get some real track data. The track will be the determining factor to dailing your combo in under real world conditions
Posted By: JAKE68

Re: dyno results... not happy diagnosis please - 08/26/11 01:21 PM

Two things. First I like the evenger carb. It runs real clean and has a great fuel curve. Was your cruise a/f way lean that you had to richen the primaries? If that was good I would not have richen up the primaries. Also was the dyno a dynojet type that is a fixed wieght or was it a eddy curent type? The fix wieght type are more repeatable. Also you would really need to see the acual resaults at the track. The dyno is only a tuning tool. I am surprised that the no. went down with the gear change ussaully they go up with more gear. Put the other carb on and see what happens. Jake
Posted By: sixpackgut

Re: dyno results... not happy diagnosis please - 08/26/11 01:24 PM

Quote:

Loose torque converters on chassis dyno's often lead to results that don't match actual performance. A manual trans would help make the playing field more level. I assume this is the same dyno used in the previous testing? What info was the dyno operator able to give about the results?



This
Posted By: JAKE68

Re: dyno results... not happy diagnosis please - 08/26/11 01:29 PM

Just went back and read your post and realized that you changed converters. That is a big difference on the dyno. Also it seams to be to much converter for that combo.imo
Posted By: MikeyT

Re: dyno results... not happy diagnosis please - 08/26/11 01:55 PM

Opps sorry, it had been a long day! I had a 4200 converter, but we pulled it and had it tightened up to 3800, sorry for the confusion.

So scratch that 3800 stall, not 4200.

Mike
Posted By: Mr.Yuck

Re: dyno results... not happy diagnosis please - 08/26/11 02:00 PM

Seems off. Your jetting seems low for a 440. I ran a much milder 440 set up w/ a proformed main body 750DP and ran 76/84's seemed to work well. What is your timing set at? You'd probably do well with it all in full around 2400 and 38*. I take it that is rear wheel HP???
Posted By: joedust451

Re: dyno results... not happy diagnosis please - 08/26/11 07:59 PM

If your happy with its perf. who cares what ANY dyno tells you, just a waiste of $$$ IMO, I never use them & never will, just take it to the track & tune there, thats "real world".

If i had a $1.00 for everytime someone ask me how much HP i was running in my duster i'd have a pocket full of $$$ & would pay for my entry fees each time , I would always tell them "enough to run 10s" LOL, it runs good & i'm very happy with it & thats that .
Posted By: Dodgem

Re: dyno results... not happy diagnosis please - 08/26/11 09:04 PM

yes wrong cam degree move it to 105 and it will be all good!
Posted By: ZIPPY

Re: dyno results... not happy diagnosis please - 08/26/11 09:18 PM

Not every converter has exactly the same torque multiplication.

Testing multiple changes to the engine is fine, but the converter swap did away with any chance of comparing last week's results to the new results.
Posted By: MR_P_BODY

Re: dyno results... not happy diagnosis please - 08/26/11 09:22 PM

Quote:

Afr's were good most of pull around 12.5 and at about 5600 started to richen up a bit.

Things I did, were jet it up, up front to 76 and backed off a bit in back 78 jets, which was a 2 jet sized up and one down in back

Timing was 36 all in At 3000 rpms

Mike



At 12.5 I would try to lean it down just a bit to
try and get 12.8 to 13.... then try it at the track
to get the best MPH on jetting
Posted By: dennismopar73

Re: dyno results... not happy diagnosis please - 08/26/11 10:00 PM

heavy car, chassie dyno means 0 to me , so i agree with the statements
as for the cam, wouldnt have went with that tpe of cam,
c/l something in the 105, range , and install at 102 range ,
as for carb, more jetting please, i run my jets in the 80 on gas,
3800 vert not bad for the street , be fine and some racing, it will get you point a to b just fine,
391 gears be just great, i ran same in my rr for 12 years.
TAKE IT TO THE TRACK, take some extra jets, timming light,
and that other carb, really dont thing much in changing it , but it may be set up diffrently, so it may work a little better for tuning purposes,
make hit without doing anything. then make a change, timming would be good start off, heavy car, 34-36 deg ,
then change carb, take a hit,
so on, just dont make several changes , because you could lose what
trying to gain,
Posted By: MikeyT

Re: dyno results... not happy diagnosis please - 08/27/11 12:34 AM

Again thank you all for your support. I guess nexct thing is to bring it to the track and dial it in with timing light and jet.

After this who thinks i should go and degree that cam to 105 LSA?

MIke
Posted By: joedust451

Re: dyno results... not happy diagnosis please - 08/27/11 01:07 AM

Quote:

Hi guys

I was excited last week took the car to the dyno to see what result happened from my changes to the car.

Ok here is car last year
4040 with me in it
440 40 over 9.5:1 compression ratio
440stealth heads
comp cam XE 268 degreed to 107 LSA
770 street avenger carb
street dominator intake
shorty style headers
727 2600 stall converter
3:23 gears
uncapped headers thru 2.5 inch cutouts

HP 327
Torque 404

Ok tonight

4040 with me in it
440 40 over 9.5:1 compression ratio
440stealth heads
comp cam XE 274 put in straight up at 110 LSa
750 Holley Double pumper 76/78
street dominator intake
shorty style headers
727 4200 stall converter
3:91 gears
uncapped headers thru 2.5 inch cutouts

HP 311
Torque 334!

ok, I'm down 16 HP and 70 lb of torque!

It doesn't make sense!

The car runs beautifully, pulls strong now all the way up to 5800 rpms! It is a blast to drive. It comes out of the hole like its on fire now.

Why would I be down?

Thanks for any info

Ok for the record temp and humidity for pretty similar!

Take it away fella's

Mike



If it were mine, I would have gone with around 10.7.1 Compression with the Aluminum heads & The XE284H or 285HL.

76 jets are a bit fat on a standard 750dp. IMO, I'd start off with 72/80-82 & go from there, I ran 74/82 in my PF 750dp, of coarse yours may very.
Posted By: Chris'sBarracuda

Re: dyno results... not happy diagnosis please - 08/27/11 01:21 AM

Would have been nice to know cylinder pressure of each cam..

Dynamic hp to the rear (3.91's) should make the car run better.

I would have milled the heads..


Chris..
Posted By: Dodgem

Re: dyno results... not happy diagnosis please - 08/27/11 03:54 AM

installing that cam at 110 is good for high RPM roundy rounds or something that does not drop below 6300??
definatley go for 106 or 105 and you will like it!.
Posted By: MR_P_BODY

Re: dyno results... not happy diagnosis please - 08/27/11 04:02 AM

Quote:

Again thank you all for your support. I guess nexct thing is to bring it to the track and dial it in with timing light and jet.

After this who thinks i should go and degree that cam to 105 LSA?

MIke



I would advance it at least 4*
Posted By: MikeyT

Re: dyno results... not happy diagnosis please - 08/27/11 04:13 AM

Ok cool S

So noob question #23567!
Advancing it would be like to 106 right?

Next one is for you Mr yuck! Why would you say bring 36 degrees in at 2400 verses 3000 rpms? I've always heard that 3000 was the rule of thumb, what advantages do I get by bringing it all in early and locking it there?

Mike

I hope this doesn't get old, but you all are awesome!
Posted By: Sport440

Re: dyno results... not happy diagnosis please - 08/27/11 04:24 AM

Advance it around 4+* from its 110. But before you do, do a compression test for a before and after comparison.

With your combo I would never install that cam at a 110 ICA. Disregard any results from the Dyno from the 2600 stall vert vs the 4200 stall vert and said combos. To many variables, even the Dyno cant figure it out.
Posted By: RobX4406

Re: dyno results... not happy diagnosis please - 08/27/11 04:24 AM

Mikey,

Here's what I see. You took a smaller cam that was advanced to 107ICL out and put a longer duration cam and put it in 3* retarded (110ICL) from the smaller cam. I believe comp recommends that 274 cam be installed at 106. You likely gave up quite a bit of cylinder pressure doing this and took some "punch" out of the engine.

Chassis dynos and loose converters don't play well as others have mentioned, including someone that uses one for his business if I'm not mistaken.

Redegree the cam to 106ICL and jet the carb for max MPH at the track. If that means going up on each side, then do so. If it takes less jet, then do that. What other people have for jetting, take that as a rough idea. There are other factors that play into what size jet you'll end up with depending on the carb and metering blocks you have. I'd start with the box stock jetting the carb came with and start again from there. Do one change at a time as mentioned.

As far as timing and where it all comes in, won't make a hill of beans difference IMO. You have a 4200 converter. As long as it's all in before that, run it! The 3000 curve should be OK. MSD distributor, run two medium springs, medium/light or two lights and NEVER run either of the heavy byatches for springs they come with!

Most of all have fun with it and don't get frustrated!
Posted By: MR_P_BODY

Re: dyno results... not happy diagnosis please - 08/27/11 04:28 AM

Quote:

Ok cool S

So noob question #23567!
Advancing it would be like to 106 right?

Next one is for you Mr yuck! Why would you say bring 36 degrees in at 2400 verses 3000 rpms? I've always heard that 3000 was the rule of thumb, what advantages do I get by bringing it all in early and locking it there?

Mike

I hope this doesn't get old, but you all are awesome!



Yes advancing it would be 106 (any number lesser than
the 110), which is your LSA.... check the P to V
clearance when you make a change like this
Posted By: Charger VJ RB

Re: dyno results... not happy diagnosis please - 08/27/11 05:13 AM

I must be way off here, but that comp cam has 110 LSA and cannot be changed unless reground. It has 106 intake CL so this = 114 exhaust? Centerline, any amount of advance or retard still comes back to 110 LSA ?

There seems merit in a 105 LSA with your 4040 weight http://speedtalk.com/forum/viewtopic.php?f=1&t=938
Maybe a custom cam grind to suit your combination
Posted By: drago

Re: dyno results... not happy diagnosis please - 08/27/11 05:23 AM

Hi,
silly question but.. was it the same dyno?
Posted By: Sport440

Re: dyno results... not happy diagnosis please - 08/27/11 05:35 AM

Quote:

I must be way off here, but that comp cam has 110 LSA and cannot be changed unless reground. It has 106 intake CL so this = 114 exhaust? Centerline, any amount of advance or retard still comes back to 110 LSA ?

You are way off! Most here, understand the difference between a Fixed "LSA vs a Adjustible installed ICL.
Posted By: Charger VJ RB

Re: dyno results... not happy diagnosis please - 08/27/11 05:48 AM

Hmm still unclear any good links for enlightenment, sorry to op.
Posted By: Evil Spirit

Re: dyno results... not happy diagnosis please - 08/27/11 06:06 AM

Quote:

Ok cool S



Next one is for you Mr yuck! Why would you say bring 36 degrees in at 2400 verses 3000 rpms? I've always heard that 3000 was the rule of thumb, what advantages do I get by bringing it all in early and locking it there?

Mike

I hope this doesn't get old, but you all are awesome!



2400 VS 3000RPM to full advance won't mean squat with a 3800 stall converter
Posted By: MikeyT

Re: dyno results... not happy diagnosis please - 08/27/11 06:15 AM

Yup same dyno!

Mike
Posted By: Sport440

Re: dyno results... not happy diagnosis please - 08/27/11 06:16 AM

Quote:

Hmm still unclear any good links for enlightenment, sorry to op.



No links needed A cams lobe seperation angle is fixed, as it is ground in as you stated.

Performance cam installations will install the cam around a 102 to a 110 ICL. Most closer to 104 range with these Mopar cams
Posted By: MikeyT

Re: dyno results... not happy diagnosis please - 08/27/11 07:18 AM

Quote:



Yes advancing it would be 106 (any number lesser than
the 110), which is your LSA.... check the P to V
clearance when you make a change like this




So is their a neat way to check p and v clearance while the head is still on the engine or do I have to pop off the head?

Mike
Posted By: MR_P_BODY

Re: dyno results... not happy diagnosis please - 08/27/11 01:58 PM

Quote:

Quote:



Yes advancing it would be 106 (any number lesser than
the 110), which is your LSA.... check the P to V
clearance when you make a change like this




So is their a neat way to check p and v clearance while the head is still on the engine or do I have to pop off the head?

Mike



If you dont want to pull the valve springs on a cyl
you can do it IF you have adjustable rockers...
takes a bit of time but... starting at 10* before
TDC turn the adjuster till it touches... thats .041
per full turn... keep doing the same thing for every
degree to about 10* after TDC... write your numbers down
Posted By: joshking440

Re: dyno results... not happy diagnosis please - 08/27/11 02:27 PM

carb seems a bit to small buddy
Posted By: 440Jim

Re: dyno results... not happy diagnosis please - 08/27/11 03:17 PM

My thoughts.

1) The new cam should be installed about 106 intake lobe centerline (110 LSA ground on the cam).

2) The new converter could be effecting the chassis dyno numbers, especially the torque peak.

3) Even if the engine is actually down slightly in peak hp (that is an if), I think the changes will make the car faster on the track. But readjusting the cam would be on my list of things to do.

Since you said the cam was put in "straight up", does that mean you aligned the sprockets dot-to-dot? If so, the ICL might be lower than 110, but without a degree wheel there is no way to know. But I suspect the cam needs to be advanced 3-5 degrees from where it is now.
Posted By: MikeyT

Re: dyno results... not happy diagnosis please - 08/27/11 05:24 PM

Ok, so here is the plan
1) Keep timing at 36 at 3000 rpm
2) Take her to the track to jet for MPH
3) At some point advance the cam

Does that seem about right?

And to answer your Question Mr. P Body, unfortunately the car does not have adjustable rockers but Harland sharp rollers
mike
Posted By: Cab_Burge

Re: dyno results... not happy diagnosis please - 08/27/11 06:34 PM

Quote:

Ok, so here is the plan
1) Keep timing at 36 at 3000 rpm
2) Take her to the track to jet for MPH
3) At some point advance the cam

Does that seem about right?

And to answer your Question Mr. P Body, unfortunately the car does not have adjustable rockers but Harland sharp rollers
mike

Mike, what do you mean? I have two sets of Harland sharp rockers on motors, they are both adjsutable with full needle bearing on the rocker shafts
Posted By: MikeyT

Re: dyno results... not happy diagnosis please - 08/27/11 08:32 PM

Cool, that is good! I didn't realize that I thought that they were set rockers and not adjustable at all! Both times I had them set up, my engine guy helped me set it up.

Mike
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