Time slip and dyno sheet don't match (need advice)

Tech questions that don't fit above forums

Moderator: Team

Jdm1027
New Member
New Member
Posts: 9
Joined: Fri Aug 29, 2014 5:52 pm

Time slip and dyno sheet don't match (need advice)

Post by Jdm1027 » Thu Oct 30, 2014 7:37 pm

Is something wrong with my comb.
Motor made 574 hp and 572 tq on engine dyno. Motor is 418 sb mopar stroker motor. It is in a 72 challenger street car with stock rear suspension, 3.55 gear and a reworked converter from ptc roughly 3800 stall. A competition 727 from tci. Car weighs 3800 with me in it. The best time so far is 7:44 @91 mph in the 1/8. With a 26x10 slick on it. 60 ft times are 1.6. I am looking to try some caltracs on the rear but I just don't feel the mph matches the hp.

Jdm1027
New Member
New Member
Posts: 9
Joined: Fri Aug 29, 2014 5:52 pm

Re: Time slip and dyno sheet don't match (need advice)

Post by Jdm1027 » Fri Oct 31, 2014 11:25 am

I am new to this site is this the place to post such a question??????? Thanks

User avatar
Dave Koehler
Guru
Guru
Posts: 3323
Joined: Mon Oct 04, 2004 11:19 pm
Location: Urbana, IL USA
Contact:

Re: Time slip and dyno sheet don't match (need advice)

Post by Dave Koehler » Fri Oct 31, 2014 11:39 am

The more knowledgeable will chime in but the numbers they give you are corrected.
Are you running at sea level on a 60 degree day with no humidity? If so then I think you are missing some HP or there is an anchor in the car.
Dave Koehler - Koehler Injection
Fuel Injection - Nitrous Charger - Balancing - Nitrous Master software
http://www.koehlerinjection.com
"Never let a race car know that you are in a hurry."

User avatar
Baprace
Guru
Guru
Posts: 1584
Joined: Sun Aug 06, 2006 4:57 am
Location: Henrietta NY 14623

Re: Time slip and dyno sheet don't match (need advice)

Post by Baprace » Fri Oct 31, 2014 12:40 pm

Try this link from Stan Weiss, he has some formulas that help estimate horsepower.

http://users.erols.com/srweiss/calchpm8.htm

Jdm1027
New Member
New Member
Posts: 9
Joined: Fri Aug 29, 2014 5:52 pm

Re: Time slip and dyno sheet don't match (need advice)

Post by Jdm1027 » Fri Oct 31, 2014 3:39 pm

I ran the nmbers on that site and on wallace calculator and they both estimate about 410 to 425 hp at flywheel. Am i loosing that much power from stock suspension. Shouldnt my mph be up even if my times were slow??

User avatar
Dave Koehler
Guru
Guru
Posts: 3323
Joined: Mon Oct 04, 2004 11:19 pm
Location: Urbana, IL USA
Contact:

Re: Time slip and dyno sheet don't match (need advice)

Post by Dave Koehler » Fri Oct 31, 2014 3:58 pm

I'll try this again. Check your UNcorrected HP numbers from that dyno sheet. Those are more realistic, particularly if your dyno and your dragstrip are in the same local area.
Dave Koehler - Koehler Injection
Fuel Injection - Nitrous Charger - Balancing - Nitrous Master software
http://www.koehlerinjection.com
"Never let a race car know that you are in a hurry."

Jdm1027
New Member
New Member
Posts: 9
Joined: Fri Aug 29, 2014 5:52 pm

Re: Time slip and dyno sheet don't match (need advice)

Post by Jdm1027 » Fri Oct 31, 2014 5:41 pm

Sorry, All I recieved was corrected numbers on my sheet,

Kevin Johnson
Guru
Guru
Posts: 7035
Joined: Tue Nov 22, 2005 5:41 am

Re: Time slip and dyno sheet don't match (need advice)

Post by Kevin Johnson » Fri Oct 31, 2014 6:26 pm

Jdm1027 wrote:Sorry, All I recieved was corrected numbers on my sheet,
Josh, is your dyno in Philippi? You can look up the weather on the day you tested there or wherever the dyno is and try to calculate backwards to the uncorrected numbers. Check the elevation and weather at the track as well.

http://www.wunderground.com/weather-for ... lippi.html

User avatar
thedynoguy
Member
Member
Posts: 78
Joined: Mon Jan 21, 2013 11:47 am
Location: Webster, New York

Re: Time slip and dyno sheet don't match (need advice)

Post by thedynoguy » Sat Nov 01, 2014 10:23 am

just call the dyno shop and get the uncorrected numbers...

User avatar
John Wallace
Guru
Guru
Posts: 1277
Joined: Tue Jan 04, 2005 10:20 am
Location: was Central Illinois - Now in Sunny Florida!
Contact:

Re: Time slip and dyno sheet don't match (need advice)

Post by John Wallace » Mon Nov 03, 2014 10:06 am

I'd say your MPH matches the ET great. So does the 60'

Now the ET/MPH are for a 465/470 HP engine.

So, you're not using a 100HP somewhere.
Could be as these guys are saying is the weather/dyno numbers are making your HP numbers higher than what you raced at.

If you are at sea level in 70º calm weather when you ran those times, then you should be running faster.
(possibly 6.9's in 1/8th)
John Wallace
Pontiac Power RULES !
www.wallaceracing.com

fdicrasto
Expert
Expert
Posts: 539
Joined: Wed Sep 26, 2012 3:44 pm

Re: Time slip and dyno sheet don't match (need advice)

Post by fdicrasto » Thu Nov 06, 2014 10:27 am

Did the shop that built the motor also dyno the motor ?

Jdm1027
New Member
New Member
Posts: 9
Joined: Fri Aug 29, 2014 5:52 pm

Re: Time slip and dyno sheet don't match (need advice)

Post by Jdm1027 » Thu Nov 06, 2014 3:25 pm

Yes sir, I emailed them to get the uncorrected numbers but have not heard from them, He is the one telling me something is wrong with my comb and I should be turning better times. I just thought that with 3:55 in the 1/8 and stock suspension with old worn out air shocks that was what was hurting my times.

User avatar
Stan Weiss
Guru
Guru
Posts: 3344
Joined: Tue Feb 20, 2007 1:31 pm
Location: Philadelphia, PA
Contact:

Re: Time slip and dyno sheet don't match (need advice)

Post by Stan Weiss » Fri Nov 07, 2014 8:48 am

Jdm1027 wrote:Sorry, All I recieved was corrected numbers on my sheet,
Can you post a copy of your dyno sheet?

Stan
Stan Weiss / World Wide Enterprises
Offering Performance Software Since 1987
Image
http://www.erols.com/srweiss/index.html

Jdm1027
New Member
New Member
Posts: 9
Joined: Fri Aug 29, 2014 5:52 pm

Re: Time slip and dyno sheet don't match (need advice)

Post by Jdm1027 » Fri Nov 07, 2014 9:54 am

dyno.jpg

User avatar
Stan Weiss
Guru
Guru
Posts: 3344
Joined: Tue Feb 20, 2007 1:31 pm
Location: Philadelphia, PA
Contact:

Re: Time slip and dyno sheet don't match (need advice)

Post by Stan Weiss » Sat Nov 08, 2014 1:18 am

Jdm1027 wrote:
dyno.jpg
That is the only information on your dyno sheet?

Stan
Stan Weiss / World Wide Enterprises
Offering Performance Software Since 1987
Image
http://www.erols.com/srweiss/index.html

Post Reply