Is it worth Dyno tuning? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 07-23-2010, 05:06 PM
Show me the money !
 
Last photo:
Join Date: Mar 2010
Location: Massachusetts
Age: 45
Posts: 183
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Is it worth Dyno tuning?

I have been driving my new built 402 sbc for about 3 months now and I really want to get the most out of it. The local dyno -tune shop wants 425.00 for a full tune. It seems to me I can get most of whats left in her myself with a little time and short money. I have never done anything to a carb other than rebuild it with stock parts. I have a .020 over 400ci with a CC 270HR , RHS (220) heads, 9.7 -9.9 CR. ,Weiand stealth manifold and one of those Summit 750 carbs on it. I know there is more power in there, I just need to extract it. It does hesitate when I stomp it, but if I roll into it , it really pulls hard. I have been told to get the vac pressure and change the cam or pump shooter . It looks like the summit carb uses holley parts .The kits I found @ summit are http://www.summitracing.com/parts/SUM-M08040/

and http://www.summitracing.com/parts/HLY-20-12/

So, I'm into this for about 80 bucks. I feel comfortable in doing the work but how will I know if I am leaving anything (HP) in there? Do these Dyno shops really give you 425 .00 worth ? I have never had a Dyno and work hard for my money. Help Me Hot rod Nation!! what would you do ?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 07-23-2010, 06:00 PM
Registered User
 
Last photo:
Join Date: Apr 2007
Location: Seattle, Wa
Posts: 6,694
Wiki Edits: 0

Thanks: 3
Thanked 404 Times in 349 Posts
Quote:
Originally Posted by Fast 4 Door
I have been driving my new built 402 sbc for about 3 months now and I really want to get the most out of it. The local dyno -tune shop wants 425.00 for a full tune. It seems to me I can get most of whats left in her myself with a little time and short money. I have never done anything to a carb other than rebuild it with stock parts. I have a .020 over 400ci with a CC 270HR , RHS (220) heads, 9.7 -9.9 CR. ,Weiand stealth manifold and one of those Summit 750 carbs on it. I know there is more power in there, I just need to extract it. It does hesitate when I stomp it, but if I roll into it , it really pulls hard. I have been told to get the vac pressure and change the cam or pump shooter . It looks like the summit carb uses holley parts .The kits I found @ summit are http://www.summitracing.com/parts/SUM-M08040/

and http://www.summitracing.com/parts/HLY-20-12/

So, I'm into this for about 80 bucks. I feel comfortable in doing the work but how will I know if I am leaving anything (HP) in there? Do these Dyno shops really give you 425 .00 worth ? I have never had a Dyno and work hard for my money. Help Me Hot rod Nation!! what would you do ?
If you need to have all it will deliver, a dyno tune is the easiest way of getting it.

You can get most of what it has yourself but typically the term "a little time" doesn't apply as you have to use the old fashion cut and try methods which tend to eat up a lot of time as you try various combinations; test them for their results and re-modify and adjust then test again.

Bogie
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 07-23-2010, 06:18 PM
Registered User
 
Last photo:
Join Date: Jul 2004
Location: At Speed
Age: 51
Posts: 1,333
Wiki Edits: 0

Thanks: 2
Thanked 27 Times in 27 Posts
The stumble/hesitation is a driveability issue and a dyno tune will not probably not improve it. Most all dyno tuning is for wide open throttle, only. If they will adjust timing, correct jetting, and rework the accel pump and secondary opening for $425, then its a good deal.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 07-23-2010, 06:32 PM
F-BIRD'88's Avatar
Yada Yada Yada
 
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,560
Wiki Edits: 0

Thanks: 3
Thanked 335 Times in 332 Posts
Almost impossible to solve most drivability issues on the typical chassis dynos most shops have.
You need a dyno that can load down the motor at various loads and speeds.
Eddy current type.

Most of the chassis dyno shops have a inertial type, (dynojet) You are tuning a big drum of a known mass. Good for acceleration testing but thats about it.

The cam in your 400 with huge 220cc port heads is really small.

You could spend 425 and get 30hp or spend $300 on a real cam and pick up 100 hp.

Is there some reason you went with such a small cam in this motor?

Most of the drivability problems you can solve yourself with a vacuum gauge, a simple narrow band afr meter/ 02sensor and drive test tuning.
It takes time to do this.
The chassis dyno shop will also charge you for any and all tuning parts used to tune your car unless you bring them.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 07-23-2010, 08:57 PM
Show me the money !
 
Last photo:
Join Date: Mar 2010
Location: Massachusetts
Age: 45
Posts: 183
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by F-BIRD'88
Almost impossible to solve most drivability issues on the typical chassis dynos most shops have.
You need a dyno that can load down the motor at various loads and speeds.
Eddy current type.

Most of the chassis dyno shops have a inertial type, (dynojet) You are tuning a big drum of a known mass. Good for acceleration testing but thats about it.

The cam in your 400 with huge 220cc port heads is really small.

You could spend 425 and get 30hp or spend $300 on a real cam and pick up 100 hp.

Is there some reason you went with such a small cam in this motor?

Most of the drivability problems you can solve yourself with a vacuum gauge, a simple narrow band afr meter/ 02sensor and drive test tuning.
It takes time to do this.
The chassis dyno shop will also charge you for any and all tuning parts used to tune your car unless you bring them.

Yeah, I know it is small, I wanted to go bigger and was talked down by my engine expert because It is my daily driver and rarely turns over 6000. It sounds and drives great but I wanted a little more chop. Maybe I will consider upping the cam at a later date,but for now, I have to run this one and just want the most out of it. As far as the heads go, I figured I will probably have them for the rest of my life (if they last that long) and RHS said they would be pretty good w/ the 270 ( and they are ) and there is plenty of room for more cam in the future.

Getting back to the Dyno, sounds like a bunch of smoke and mirrors to me I think I will pick up a vac gauge and start from there. I won't learn anything if I don't do it myself. Also, Do you think it would be worth it to pick up the summit tuning dvd for their carb ? Or is it going to be the same old trial and error ? Right after I bought the 750, ( like a week later) they came down on price and threw in the dvd, now, to get it separate they want 25.00 for it.
I forgot to mention its a two bolt
BTW - What would you consider for a cam given the application?

Thanks,
Matt

Last edited by Fast 4 Door; 07-23-2010 at 09:31 PM.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 07-23-2010, 09:25 PM
Show me the money !
 
Last photo:
Join Date: Mar 2010
Location: Massachusetts
Age: 45
Posts: 183
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by oldbogie
If you need to have all it will deliver, a dyno tune is the easiest way of getting it.

You can get most of what it has yourself but typically the term "a little time" doesn't apply as you have to use the old fashion cut and try methods which tend to eat up a lot of time as you try various combinations; test them for their results and re-modify and adjust then test again.

Bogie

Bogie,

The Dyno shop Will give me 4 pulls for 75.00 .( of course they won't let me work on it between pulls ) That being said, The only real "test" is at the track, something we don' t have nearby. The other "test" site is a stopwatch and a couple of landmarks on a nice flat straight road,that we have Risky but effective. I don't really trust any mechanics that I don't know. I don't think I am willing to muster up the 425 for some dude to wrench on my car but 75 bucks seems to be reasonable for some data, plus I am curious what she's packin. What do you think ? Will the data from a dyno help us figure out what to do,or will it be no help at all without follow ups ?

I don't know, could be wasting my time ( and yours) It just feels like it wants to go more but something in that big old 4-door is holding it back. I think I am going to get a quick 4-pulls and some results.

Does anyone know what kind of power this thing should be making ?

Thanks for all the help, I appreciate it.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 07-23-2010, 09:47 PM
F-BIRD'88's Avatar
Yada Yada Yada
 
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,560
Wiki Edits: 0

Thanks: 3
Thanked 335 Times in 332 Posts
four door:
I have to charge a bit extra to put on my "Amazing Carrnac" hat and guess at your specific car/engine combo details. " Remote viewing" makes my head hurt.

If you let me in on this I will recommend a good cam for free.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 07-23-2010, 10:56 PM
Show me the money !
 
Last photo:
Join Date: Mar 2010
Location: Massachusetts
Age: 45
Posts: 183
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by F-BIRD'88
four door:
I have to charge a bit extra to put on my "Amazing Carrnac" hat and guess at your specific car/engine combo details. " Remote viewing" makes my head hurt.

If you let me in on this I will recommend a good cam for free.
Is that from Johnny Carson? Ha, My memory hurts. Sorry, I really don't have a lot of technical knowledge so you need to have a little more patience with me. I will try to give you what I remember.

Daily street driver 1965 Belair 4-door. . its heavy ( Weight unknown )
stock rear end ?
405 ci. 2-bolt
flat top hyper speed pro pistons
stock rods - 5.56
9.95 - 1 CR deck .025
RHS 12305-02 72cc 220 runner 2.02 -1.6 (.600max lift)
TH 400 trans.
Weiand stealth manifold ( square bore )
summit 750 cfm
HEI dist. with MSD http://www.summitracing.com/parts/MSD-8501/
1-5/8 " full length headers
CC H.P. double roller chain
CC Retro HR lifters
CC H.P rods
PRW roller rockers 1.5


if it's for free its for me !
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 07-24-2010, 05:48 AM
Registered User
 
Last photo:
Join Date: Apr 2010
Location: Hawaii
Posts: 373
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Looks like a good "torque" set-up. With the stock-length rods, you're limited on rpm. But it's not an issue if it won't see high rpm. Since you're pulling 4000lbs+ in weight, torque would be more important...especially with stock gearing (and possibly a stock converter). I like the set-up, even though 220 is a little big in my opinion. But with the last 406 I built, the one regret I had was not investing in better heads, like you did. With your heavy-car/stock gearing, your engine's a pretty good match. Just have to get rid of that stumble. In my opinion you should do it yourself. Anybody can pay someone else to do it...but what will they learn? Nothing. Do it yourself and you'll learn something you'll never forget. And it won't cost you anything but time (and some parts, of course).
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 07-24-2010, 06:38 AM
LATECH's Avatar
Hotrodders.com Moderator
 

Last journal entry: Motor - vator
Last photo:
Join Date: Jul 2010
Location: Northeast Pennsylvania
Posts: 5,173
Wiki Edits: 0

Thanks: 199
Thanked 251 Times in 233 Posts
F BIRD AND SUPERSPORT sound right. I learned one thing early on if it sounds like it makes sense its probably right. Jetting could be close on your carb but accel pump sounds like an issue. I am like F Bird I would tune it myself and make a handfull of passes out front of the house to get it dialed in. I am not to keen on other peoples work . If that carb is like a holley and memory serves me right ( been a while) the accel pump adjustment will actually work better with a small amount of travel on the lever before it moves the plunger at the diaphram. almost contrary to what you would deduct by looking at the way it works. Also timing and ported verses manifold vacuum for your advance mechanism is important. Take some time and write down the changes you make on a sheet of paper and review them as you go through the process. also make a note at the side as to wether it helped performance or hurt it.All part of the process. keeping track of where you came from can help you get where your going
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 07-24-2010, 09:35 AM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Do your testing at the track! Besides the obvious, the trap speed is a good indication of HP. The money you save in tickets (God forbid you hurt someone else while doing your "testing") will be better spent for a test and tune day or two at your local strip.

My take on the dyno tune deal is, if you cannot work on the engine between passes, what's the point? Just an inertia-type "hamster wheel" will not tell you much about the real world performance. Even timing optimized on a dyno will not always equate to a usable setting, given the differences in air temps and ambient conditions- although they WILL show you what to get as close to as the real world will allow.

In your case, the cam isn't too small, the ports are too big, IMO.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
350 engine overheating on dyno and since betty55 Engine 12 05-26-2009 03:04 PM
Another Carb Tuning ?...TECH @ BG Help Docs91RS Engine 2 05-26-2005 11:30 AM
Car missing while on Dyno? FBody Engine 11 09-07-2004 10:17 AM
what first? advance curve or carb tuning? dirtydave Engine 3 11-07-2003 04:42 PM
One Stop Dyno Tuning ProPCMTuner Engine 1 12-09-2002 03:29 PM


All times are GMT -6. The time now is 08:25 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.