Dyno results before turbo charging
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Results 1 to 11 of 11
Northstar Engines and System Technical Discussion Discussion, Dyno results before turbo charging in Cadillac Engine Technical Discussion; Ok guys I took the car to the dyno this weekend for some baseline numbers before I turbo charge it. ...
  1. #1
    MARK99STS is offline Cadillac Owners Fanatic
    Automobile(s): 99 STS
    Join Date
    Aug 2003
    Age
    59
    Posts
    149

    Dyno results before turbo charging

    Ok guys I took the car to the dyno this weekend for some baseline numbers before I turbo charge it. Now that I can control the air/fuel trim I wanted to experiment. Got some interesting results.
    1st pull was running stock program. As expected the A/F was very rich(typical GM) at about 11.8:1 (251 HP, 252 torque).
    2nd pull I backed off the fuel and it ran fairly lean at 13.8-14:1, but the HP and torque stayed nearly identical (250HP, 250T)
    3rd pull I split the difference and got the fuel trim to 12.8:1 and as you can already guess the HP and Torque stayed the same. The guys at the dyno said they had only seen this happen with a Cobra Mustang running the 4.6l doubleoverhead cam motor. Very wierd. We did a final run unplugging the IAT sensor which made the computer think the air temp was -40 in hopes to increase the timing but the results were still the same.
    The only other dyno results I have seen for the STS were from Corsa when they compared their exhaust with and without. Their results were 206 HP and 227 HP, so I am significantly higher than that.
    Anybody have any thoughts as to how the HP does not change with a change in A/F ratio?
    --------------------
    MARK 99STS
    14.1 qtr. actual track time
    http://www.markonemtg.com/marks99sts

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    mcowden is offline Cadillac Owners Connoisseur
    Join Date
    Jun 2003
    Posts
    1,164

    Re: Dyno results before turbo charging

    Quote Originally Posted by MARK99STS
    Ok guys I took the car to the dyno this weekend for some baseline numbers before I turbo charge it. Now that I can control the air/fuel trim I wanted to experiment. Got some interesting results.
    1st pull was running stock program. As expected the A/F was very rich(typical GM) at about 11.8:1 (251 HP, 252 torque).
    2nd pull I backed off the fuel and it ran fairly lean at 13.8-14:1, but the HP and torque stayed nearly identical (250HP, 250T)
    3rd pull I split the difference and got the fuel trim to 12.8:1 and as you can already guess the HP and Torque stayed the same. The guys at the dyno said they had only seen this happen with a Cobra Mustang running the 4.6l doubleoverhead cam motor. Very wierd. We did a final run unplugging the IAT sensor which made the computer think the air temp was -40 in hopes to increase the timing but the results were still the same.
    The only other dyno results I have seen for the STS were from Corsa when they compared their exhaust with and without. Their results were 206 HP and 227 HP, so I am significantly higher than that.
    Anybody have any thoughts as to how the HP does not change with a change in A/F ratio?
    --------------------
    MARK 99STS
    14.1 qtr. actual track time
    http://www.markonemtg.com/marks99sts
    Maybe if it detects no signal from the IAT sensor, it assumes the previous value for a while before setting a DTC. If you plugged in a resistor with the appropriate value to force an air temp of -40, I would expect different results. Just a thought anyway.

    Maybe it's just that your readings are inaccurate. Where are you reading the actual A/F ratio? Maybe you're reading the value as specified by the TPS but not after O2 sensor, MAF, etc. compensations? I have no idea. It's the only thing I can think of.
    Mike

  4. #3
    eldorado1 is offline Cadillac Owners Connoisseur
    Join Date
    Feb 2004
    Location
    FL
    Posts
    2,250

    Re: Dyno results before turbo charging

    are you reading with a wideband?

    how are you changing the fueling?

    btw- is this a completely stock STS? Your results are encouraging - 17% drivetrain loss. I've seen dynos put the 4t80e at 25% loss!! (Maybe they were just old?)

  5. #4
    MARK99STS is offline Cadillac Owners Fanatic
    Automobile(s): 99 STS
    Join Date
    Aug 2003
    Age
    59
    Posts
    149

    Re: Dyno results before turbo charging

    Quote Originally Posted by eldorado1
    are you reading with a wideband?

    how are you changing the fueling?


    Yes the dyno uses a wide band to measure A/F

    I am using a piggy back computer by PCS to control fuel.
    (see post dated 9-16: Piggyback computer is installed

    My STS is not stock. See my web site WWW.MARKONEMTG.COM/MARKS99STS

  6. #5
    eldorado1 is offline Cadillac Owners Connoisseur
    Join Date
    Feb 2004
    Location
    FL
    Posts
    2,250

    Re: Dyno results before turbo charging

    Quote Originally Posted by MARK99STS
    Yes the dyno uses a wide band to measure A/F
    I am using a piggy back computer by PCS to control fuel.
    (see post dated 9-16: Piggyback computer is installed
    My STS is not stock. See my web site WWW.MARKONEMTG.COM/MARKS99STS
    HTTP 404 - File not found
    okay, so much for my hopes that the 4t80e isn't a HP hog...
    I don't know, that sounds REALLY odd. So your wideband shows the AFR changing, but no change in HP? Well then something else must be going on... Probably timing changes are happening. (i.e. running leaner puts the timing vs MAP into a higher pressure cell that reduces timing)
    edit - got the website to work, has to be all lowercase.
    so would this be with the catback, 80mmTB, and K&N? If so, that would be a 33hp gain over stock. (using the 25% loss)

  7. #6
    MARK99STS is offline Cadillac Owners Fanatic
    Automobile(s): 99 STS
    Join Date
    Aug 2003
    Age
    59
    Posts
    149

    Re: Dyno results before turbo charging

    Eldorado1,
    Yes the dyno is with my current mods which also include the exhaust side of the heads ported, but I saw no gain from that as I have not done away with the crossover pipe which is the choke point of the motor right now. When I turbo it, we will replace all exhaust from the cat forward.

  8. #7
    auroradude's Avatar
    auroradude is offline Cadillac Owners Fanatic
    Automobile(s): 95 Aurora, 08 Z06
    Join Date
    Jun 2005
    Location
    WC, PA
    Age
    26
    Posts
    244

    Re: Dyno results before turbo charging

    Wow mark you are lucky you can do all that stuff yourself man. I would kill to have that motor in my car. You got the LSD too, man so lucky..BTW where did you get that LSD from? Cant be from DP can it??

    How much were the ported & polish heads lol...2600?

    How much to date have you spent modding your northstar is what i would like to know, cause i am thinkign about doing some serious mods (brand new 4.6 mill) in the future once i pile up enough cash from this online thing i am making a killing from.

  9. #8
    MARK99STS is offline Cadillac Owners Fanatic
    Automobile(s): 99 STS
    Join Date
    Aug 2003
    Age
    59
    Posts
    149

    Re: Dyno results before turbo charging

    Quote Originally Posted by auroradude
    Wow mark you are lucky you can do all that stuff yourself man. I would kill to have that motor in my car. You got the LSD too, man so lucky..BTW where did you get that LSD from? Cant be from DP can it??
    How much were the ported & polish heads lol...2600?
    How much to date have you spent modding your northstar is what i would like to know, cause i am thinkign about doing some serious mods (brand new 4.6 mill) in the future once i pile up enough cash from this online thing i am making a killing from.
    I've got about $5,500 in it so far. The LSD is from Engineered Performance out of Atlanta.

  10. #9
    SupaStealth is offline Cadillac Owners Member
    Join Date
    Dec 2004
    Location
    MN/Milwaukee, WI
    Age
    29
    Posts
    9

    Re: Dyno results before turbo charging

    could it be that the computer is sensing the change done by your piggy back and further compensating for it?

    nice mods list by the way, can't wait to see the turbo in it

  11. #10
    thu's Avatar
    thu
    thu is offline Cadillac Owners Connoisseur
    Automobile(s): 2003 STS w/BoseNav, 1993 Deville, 1985 Deville
    Join Date
    Jul 2003
    Location
    Wyoming
    Posts
    1,089

    Re: Dyno results before turbo charging

    Mark99STS, the website no workie.

  12. #11
    MARK99STS is offline Cadillac Owners Fanatic
    Automobile(s): 99 STS
    Join Date
    Aug 2003
    Age
    59
    Posts
    149

    Re: Dyno results before turbo charging

    Quote Originally Posted by thu
    Mark99STS, the website no workie.
    Should be all lower case. Try this:

    http://www.markonemtg.com/marks99sts/

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

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.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting