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Thread: Low trap speeds - Power loss? Bad driving? Both?

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    Default Low trap speeds - Power loss? Bad driving? Both?

    Hey guys. I have a 2012 GT with the p1sc procharger (HO intercooler, not the stage 2 kit). On the first tune I was trapping 112-115 with little to no wheel spin (on street tires in 70-75 degree weather) and dynoed at 370/346 stock and 473/362 supercharged. I decided to retune hoping to get the 185hp gain advertised by procharger and a bump in torque with a Lund tune and added a BAP. Still on 7.5 boost. On this set up the car was trapping between 106-111 in 78ish degree weather. Again on street tires, but this time with some bad launches, not hooking until i shifted into 2nd. For track days I shifted at 7k rpm and the car is all stick minus the blower. Im not a good driver, so I expected to run slow times, but I've read your trap speeds should be relatively consistent unless you're having major traction issues and I would have expected a 600 crank hp (per ProCharger's claim) to trap 118-125 depending on the conditions & traction. Or am I wrong about either of these points?

    I just figured out that the alternator needs to be replaced. Ive read a faulty alternator can result in not enough electrical power for the fuel pump (and the BAP i would imagine) to function properly. Is it possible that once I replace the alternator I will just need another tune? Or is lack of seat time more likely the reason for the low trap times?



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    Last edited by prochargedstang; 09-18-2020 at 03:29 AM.
    2012 Ignot Silver Mustang GT
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    I don't think I can delete this post, but just saw on lunds site I can get a revision for free. I will just get a tune revision i swap the alternator and see where the car sits.

    On a side note, I screwed up royally not testing my alternator prior to getting the procharged installed. Changing the alternator out with the procharger installed appears to be alot more work compared to a stock car

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    Fat Tire Hotrods CMC SuperCobraJet strtcar's Avatar
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    Did you datalog your runs? I sent Lund my logs on Wed after the track day and got some revisions.

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    No. At the time I thought my bad launches were killing my trap speed on the new tune.

    Thats a good point though. Once I have the alternator replaced and get it back to the track I'll data log. Thanks for the tip

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    Fat Tire Hotrods CMC SuperCobraJet strtcar's Avatar
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    Quote Originally Posted by prochargedstang View Post
    No. At the time I thought my bad launches were killing my trap speed on the new tune.

    Thats a good point though. Once I have the alternator replaced and get it back to the track I'll data log. Thanks for the tip

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    Datalog every run

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    ^ Amateur Using Nitrous Oxide CMC Administrator MGLT's Avatar
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    It's possible that bad driving, wheel spin, etc was affecting your MPH. I know when I've run my Boss 302 down the track, I've had days where I was inconsistent and my MPH was lower than it should have been.

    Other things to check is spark plug gap. It's possible that you were blowing out the spark on the top end.

    Did anyone get weird 1/8th mile MPH on their time slips? I had three 11.0x passes, all with 1.52 60' times and 1/4 mile trap speed within .5 MPH, but I had one run where my 1/8th mile trap speed was at 104 MPH where my other 2 runs were around 98 MPH.

    Here is the time slip in question on the left compared to my previous best pass on the right. I did have about 1.5 more degrees of timing added in the new best pass, but I'm just baffled that 1/8 mile picked up so much and then 1/4 mi is unchanged, unless my converter is slipping on the top end.

    -Matt

    2012 Mustang Boss 302 - Garage Queen Edition
    1990 Mustang 5.0 LX - Round the block race car
    1988 Mustang 5.0 GT

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    Quote Originally Posted by MGLT View Post
    It's possible that bad driving, wheel spin, etc was affecting your MPH. I know when I've run my Boss 302 down the track, I've had days where I was inconsistent and my MPH was lower than it should have been.

    Other things to check is spark plug gap. It's possible that you were blowing out the spark on the top end.

    Did anyone get weird 1/8th mile MPH on their time slips? I had three 11.0x passes, all with 1.52 60' times and 1/4 mile trap speed within .5 MPH, but I had one run where my 1/8th mile trap speed was at 104 MPH where my other 2 runs were around 98 MPH.

    Here is the time slip in question on the left compared to my previous best pass on the right. I did have about 1.5 more degrees of timing added in the new best pass, but I'm just baffled that 1/8 mile picked up so much and then 1/4 mi is unchanged, unless my converter is slipping on the top end.

    Thanks for the input Matt! I have been a little preoccupied with an emissions issue, but will double check my gap and get some more practice in once the car can be registered.



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    2012 Ignot Silver Mustang GT
    Procharger & Catback

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    Quote Originally Posted by MGLT View Post
    It's possible that bad driving, wheel spin, etc was affecting your MPH. I know when I've run my Boss 302 down the track, I've had days where I was inconsistent and my MPH was lower than it should have been.

    Other things to check is spark plug gap. It's possible that you were blowing out the spark on the top end.

    Did anyone get weird 1/8th mile MPH on their time slips? I had three 11.0x passes, all with 1.52 60' times and 1/4 mile trap speed within .5 MPH, but I had one run where my 1/8th mile trap speed was at 104 MPH where my other 2 runs were around 98 MPH.

    Here is the time slip in question on the left compared to my previous best pass on the right. I did have about 1.5 more degrees of timing added in the new best pass, but I'm just baffled that 1/8 mile picked up so much and then 1/4 mi is unchanged, unless my converter is slipping on the top end.

    Also, as far as your ? goes I did notice a hellcat with weird 1/4 trap speeds while I was there in early August. He ran a 11.7 @ 106mph. I was so far behind that I can't say for sure he didn't let off but it didnt seem or sound like it

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    ^ Amateur Using Nitrous Oxide CMC Administrator MGLT's Avatar
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    Quote Originally Posted by prochargedstang View Post
    Also, as far as your ? goes I did notice a hellcat with weird 1/4 trap speeds while I was there in early August. He ran a 11.7 @ 106mph. I was so far behind that I can't say for sure he didn't let off but it didnt seem or sound like it

    Sent from my SM-G965U using Tapatalk
    It's possible that the hellcat was backing out of the throttle and coasting. Some guys will do that if they are worried about getting kicked out of the track for running too fast without safety equipment or he was just testing for 1/8 mile.
    -Matt

    2012 Mustang Boss 302 - Garage Queen Edition
    1990 Mustang 5.0 LX - Round the block race car
    1988 Mustang 5.0 GT

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    Quote Originally Posted by MGLT View Post
    Did anyone get weird 1/8th mile MPH on their time slips? I had three 11.0x passes, all with 1.52 60' times and 1/4 mile trap speed within .5 MPH, but I had one run where my 1/8th mile trap speed was at 104 MPH where my other 2 runs were around 98 MPH.
    That is very weird. In my professional opinion, that is a glitch. Okay, but in all seriousness, with how all other data points are SO similar, I do attribute that to some sort of glitch. Serious (stupid) question, are there radar guns at each of those intervals that measure the MPH?
    #triple0crew

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