Just got back from the State capitol dragway.
13.08@104.17
13.02@104.27
13.01@104.10
12.99@104.50

Weighed my H.D. just before going to the track.
With me in it-----5445lbs.

For those of you that think you need backpressure:::
Last best runs with converters was 13.6~'s @ 99.9
Removed converters with stock H.D muffler for todays best.
This is the only change that was made.
Also for those that want to change their stock H.D. muffler????I say why????

These runs were made on 26x10.5x16 e.t. streets.
(I was still slightly hazing the tires though).
going through the traps @ 5200 rpm.

I must say im tickled pink.


:db: :db: :db: :db: :db: :db: :db: :db: :db: :db: :db:

Vince

 

For those of you thats been following my previous post.
Our N/A mustang weighed in at
3060 with driver and backed up two 127 mph passes
ON THE MOTOR-----STREET CAR----93 pump gas

 

awsome times!

congrats on the 12 second club!

 

Could you tell us what mods you got?

So you are saying by removing your catalyctic converters you picked up 6/10's ??? That's a little hard to believe. I believe the times but I didn't the Cats made THAT much back-pressure.

 

Way to go!!!

 

Heres my mods:
JLP #8 lower (making 12 -13psi on the guage)
JLP chip (12.0 a/f)
Air box mod w/ K&N (4in. fresh air tube into front grill---also cut side firewall open to match the size of the boot on the air box.)
Valve body and deep pan
IT20 plugs
NO CONVERTERS--Stock muffler and pipes
26in tall tires to lower gear ratio.

ricekicker------converters and tires made this difference. thats all. Converters do have that much, especially with boost mods. I personally measured 11 psi at WOT with them on. And 1.5 with them off. Normally anything over 4 psi backpressure is seriously hampering your power gains. I will also admit that the shorter tires helped as well.

I will admit, removing them will move h.p. and torque numbers, but only because of the "tune". This fools people. Proper tuning will get you there.
Same senario as people running richer mixtures installing ignition mods "pick up" power, people with correct tunes installing ignition mods "do not".
Its really the tune.
(Both of those statements do have larger meanings and deeper explanations, and numerous variables. Im speaking from my own personal experiences with my vehicles and my customers vehicles)

Vince

 

frickin good time there LV, i'm taken my cats off today! did you have to put the O'2 sensor things on and get a new tune?

 

L.V.,
I was under the impression that when you releive/reduce backpressure,you will lower max boost readings.How did you gain .5 lb w/ less backpressure? Not saying your wrong,just wondering why..

Frank

 

Nice times welcome to the club.

I agree on the stock HD muffler I left it on but removed the pipes and put turn downs. I bet I got the same gains if not more than the bassani stuff.

I did gain 1 mph+ from that. And 1mpg also. I left the cats thou dont like it to get to loud.

What were your 60ft like ? 1/8 time? Mph ?

And did you make pass on street tires ?

I am thinking of getting some et's but it looks like I might have it hooking real good on stock tires.

Next time at the track try a tire pass versus a et's pass.

You only got 11 lbs from a 8lb lower ?

 

Good question ?

 

Holy crap I just plugged in your weather conditions in my weather station.

You had 2000-2100 FT below sea level conditions.

My best was in 1400- below sea level.

I tell you this program is fun.

Guys get out now and get you best cause when summer comes and our 12.99's turn into 13.471 @ 102.16 in 80 degree weather and some lower pressure.

I love great weather.

 

IM not an engineer, but im assuming its because the blower is still at the same speed, and the camshaft will still only let so much in and out.
Having cool dense air at the same time helps.
I would not expect to loose a whole lot of pressure anyway.

The 11psi was measured exhaust back pressure with the cats and not boost pressure.

Yes, i just welded the primary 02 bungs, and the rears are left unplugged as of now for the preliminary testing. I added 1 additional bung for the wideband.
My ratios stayed at ~12.0 and seems to not have affected any of the tune. The cats have been off for a week now. Obvioulsy i have a check engine light on. I will send back to hopefully get the rears "turned off" if you can say it like that.

Honestly the truck is making so much more seat of the pants torque, im not going to waste my time trying street tires anymore.


And unfortunately, someting was wrong with the track "printers". They were actually hand writing everyones times. The clocks, and display boards, win lights etc. were all in perfect order. Meaning that everyone was only getting reaction times, 1/4 et, and mph only. The obvious numbers that are posted on the end of track display boards. I know these times are correct, as i have numerous witnesses. I drew a crowd every time i made a pass. And i made 7 passes. IM dying to know the 60ft. But seriously, the truck had everyone in AWE. I had to be getting at least ~1.8

 

Andre over at HALO is busy doing significant testing on headers/cats/catbacks on his and a fellow L owners truck. They have found the single biggest HP gains in simply removing or replacing the stock cats with high flow versions.

I am not going to remove them, but I am considering putting bassani high flow cats in to replace.

I bought a bassani cat back, because I like the sound better. Given a swap of the cats, the stock exhaust might sound awesome...

There is a post on the L forum and on NLOC by 1BADTRK

Ken