Just came from the dyno (again...)

HPLouis

Well-Known Member
Established Member
Joined
Sep 27, 2002
Messages
1,708
Location
New York City
Hi, some backstory on my car:

First run with 2.76 pulley: https://www.svtperformance.com/threads/not-happy-at-dyno.1161444/ On this one, I had 18 degrees of timing and the stock airbox (which choked off a lot).

Second run with 3.1 pulley: https://www.svtperformance.com/thre...no-with-questions-about-my-a-f-ratio.1175083/ Now at 20 degrees of timing and still had the stock airbox.

Today, I went with a Billetflow 2.93 pulley, JLT Ram Air intake, MRT catted H-Pipe, Borla S-Type catback, Metco dual BB idler and engine pullies, Gates RPM stock sized belt, Ford AGSF12M plugs gapped at .032 and SCT tuned with a Pro Racer Package. I still have 20 degrees total timing.

This is the first run
432rwhp and 473rwtq at 13lbs

This is the second run:
438rwhp and 477rwtq at 13.5lbs

This time around, I replaced the stock airbox with a JLT Ram Air intake and I leaned it out a little bit. I also added a Metco aux idler for the belt slip and brought down the plug gap from stock to .032 for the blowout.
 
Last edited:

HPLouis

Well-Known Member
Established Member
Joined
Sep 27, 2002
Messages
1,708
Location
New York City
Sheet for the first run. We pulled to 6000:
SCAN.JPEG


We got to 13lbs of boost.

This is how the FP and Inj DC looks for 6000:
IMG_2152.JPG



Sent from my iPhone using the svtperformance.com mobile app
 

HPLouis

Well-Known Member
Established Member
Joined
Sep 27, 2002
Messages
1,708
Location
New York City
That battery voltage looked dangerously low.....might need to check alt/batt/grounds.

Yeah, I'll be looking into that for the winter storage. I took it to the Ford dealership and they said it checked out OK with their scan tool and that it's not a problem to dip into the 12's at WOT but, when I'm driving at night with the A/C on, it dips into 11.75. At idle, it's 13.8-14.2. I had the alternator replaced at the Ford dealership and the new (reman'd) one gives me the same output as the old one (dammit).
 

BlksvtCobra01

Deplorable and Proud
Established Member
Joined
Apr 10, 2008
Messages
13,555
Location
Ohio
Yeah, I'll be looking into that for the winter storage. I took it to the Ford dealership and they said it checked out OK with their scan tool and that it's not a problem to dip into the 12's at WOT but, when I'm driving at night with the A/C on, it dips into 11.75. At idle, it's 13.8-14.2. I had the alternator replaced at the Ford dealership and the new (reman'd) one gives me the same output as the old one (dammit).

Damn that is low I don’t think mine has ever dropped into the 11’s. Lowest battery voltage I ever saw was 12.5. New battery this year. I didn’t drive it for three weeks once charged the battery with a slow charger and it starts at 14.2 then after driving and heat normally stays around 13.2-13.5.




Sent from my iPhone using Tapatalk
 

HPLouis

Well-Known Member
Established Member
Joined
Sep 27, 2002
Messages
1,708
Location
New York City
Damn that is low I don’t think mine has ever dropped into the 11’s. Lowest battery voltage I ever saw was 12.5. New battery this year. I didn’t drive it for three weeks once charged the battery with a slow charger and it starts at 14.2 then after driving and heat normally stays around 13.2-13.5.




Sent from my iPhone using Tapatalk

I've got an Optima Yellow Top from 2015. Could that be a problem? I've always been told to use Motorcraft but the prior owner had this on the car so I just kept it. I thought that the battery started the car and the alternator kept it going so my low batt voltage would be the alternator and not the battery.

Am I wrong?
 

01yellercobra

AKA slo984now
Established Member
Joined
Oct 5, 2005
Messages
21,128
Location
Cali
The low voltage is from the alternator. A bad battery could drag it down. But I think you'd see other issues. Fix the voltage drop and you'll gain some head room with the pumps. You seem to want to run the smaller pulley so you might want to consider the wire upgrade. It'll give you some head room as well.
 

hotcobra03

Well-Known Member
Established Member
Joined
Mar 11, 2007
Messages
7,461
Location
poteet,texas
I've got an Optima Yellow Top from 2015. Could that be a problem? I've always been told to use Motorcraft but the prior owner had this on the car so I just kept it. I thought that the battery started the car and the alternator kept it going so my low batt voltage would be the alternator and not the battery.

Am I wrong?
The ground can cause light also.

For me I’ve had. ground cause this.

Main ground at engine mount stud.
Stud snapped,but never fell down causing intermittenting charging

And than ground on battery to radiator support. This burned up inside.
Here I noticed volts were always good but if I read from inside car power source it read 1 volt if not more lower.

Since replacing this I see 13.8-14.1 with everything on and running in heat.
 

TerminatoRS

Well-Known Member
Established Member
Premium Member
Party Liquor Posse
Joined
Jul 29, 2019
Messages
2,378
Location
Wisconsin
slo98's right. Don't fart around with OEM replacement alternators; you're just going to end up replacing them over and over. Get a beefier one (J2fab seems to be the #1 recommendation) and look over your wiring. I just installed the J2 and even though my car is a garage queen, I still had to clean up the connections. Also, take a close look at the battery post clamps. The thin stock ones like to "tear" over time in my experience. And, based on how you're progressing, you're going to need the added juice when you go with bigger injectors and boost-a-pump anyway. May as well kill two birds.
 

BlksvtCobra01

Deplorable and Proud
Established Member
Joined
Apr 10, 2008
Messages
13,555
Location
Ohio
I've got an Optima Yellow Top from 2015. Could that be a problem? I've always been told to use Motorcraft but the prior owner had this on the car so I just kept it. I thought that the battery started the car and the alternator kept it going so my low batt voltage would be the alternator and not the battery.

Am I wrong?

I’d still check the ground first as stated and lean on an alternator. That said I’ve never had luck with optima had one in my fox. Went thru three. Put it in a Bronco 2 I had before I sold it and a motor craft back in my fox. My interstate battery died in my Cobra this year I put a motor craft back in.


Sent from my iPhone using Tapatalk
 

Users who are viewing this thread



Top