LS1GTO Forums banner

1 - 9 of 9 Posts

·
Exhausted Tuner
Joined
·
1,254 Posts
Discussion Starter #1 (Edited)
Had a chance to do some tuning with a 2004 Pontiac GTO A4 - Magnacharged

Modifications:
Fuddle 3200 stall converter
K&N FIPK
MagnaFlow Catted mid-pipes
Custom MagnaFlow 3 muffler cat-back
90 MM TB
85 MM MAF


Bold items were added along with new supercharger housing

BLUE "BEFORE" Dyno - Custom Tune (Stock ported TB, OE MAF, Magancharger MP112 @ 11 PSI <1:1 rear drive / 2.9 front pulley>)street Tune 91 Octane

RED "AFTER" Dyno - Custom Tune (90 MM TB, 85MM MAF, MagnaVolt, Magnacharger MP122H MP122H @ 13 PSI <1:1 rear drive / 2.9 front pulley>)street Tune 91 Octane


MP112 Tuned (converter locked): 434 / 460
MP122H Tuned (converter locked): 485 / 457

67 Max RWHP increase
48 Max RWTQ increase

51 Peak RWHP increase
(-3) Peak RWTQ increase

Weather: 88-91* F / 17-21% Humidity

This is a WOT 2nd gear to 3rd gear pass on the dyno:


As you can see the minor trade off in torque is never seen in WOT 2nd, through the shift and 3rd gear (converter unlocked)

The gains were most impressive on paper BUT what really sells the upgrade is the feel. If you are a maggie owner / driver the feel is totally different. You never feel the sensation of the car topping out in the upper rpm band (5000-6500 rpm) ... it just keep pulling and pulling until the shift point. Don't forget this is a STOCK MANIFOLD car WITH CATS and a substantial exhaust system to suport street legal noise levels and interior comfort.

On a side note, some fueling issues need to be addressed at this point. The injector duty cucle is at 95% with the stock OE fuel pump and the Magnavolt. The fuel pressure drops from 60 to 50 PSI at WOT indicating a lack of volume under high demand.

Richard
 

·
GTO no more baaah!
Joined
·
1,150 Posts
In other words, upgrading to a larger Maggie means upgrading the fueling beyond the stock pump and booster to be safe, right? Some very nice numbers..
can't wait to see that on an LS2- 500+RWHP with stock exhaust maybe?
 

·
Oh my f*ck!
Joined
·
6,464 Posts
You realize of course that the greatest increase is due to the Rubbermaid mod. :)

Some good gains, looks like PO04GTO was right on with his 50rwhp guess. I am curious to know what this would do with my exhaust but at the same time, the hood issue makes this less desireable...Leaning more towards the AZPS cam now just due to that.
 

·
May I quote you on that?
Joined
·
22,046 Posts
That's a nice improvement over the M112. The Eatons and twin screws seem to be a little harder on the fuel system than centrifugals, as they start beating it up sooner in the RPM range. Even with 60 Lb injectors, my OEM fuel system prevented a sharper tune, as the fuel pressure was not inspiring trust.
 

·
Exhausted Tuner
Joined
·
1,254 Posts
Discussion Starter #8 (Edited)
mistermike said:
That's a nice improvement over the M112. The Eatons and twin screws seem to be a little harder on the fuel system than centrifugals, as they start beating it up sooner in the RPM range. Even with 60 Lb injectors, my OEM fuel system prevented a sharper tune, as the fuel pressure was not inspiring trust.
For the most part over fueling didn't effect A/F in the 6000 rpm + range. Running A/F at sub 10:1 to 10.5:1 to 11:1 all showed the same lean trend from 6000-6500 rpm and the same drop of fuel pressure whether Injector duty cycle was 105 or 95%.



All that just leads to the fact the stock fueling system is just not up to speed for the new powertrain combo.

The A/F will tighten up with a more adquate fuel system. Just to show how close the fuel tune is look at he second gear pass and you will see a flat A/F, but with increased load and demand in 3rd you get what you see on the chart.
 

·
May I quote you on that?
Joined
·
22,046 Posts
Yep, that's a lot of extra work when the fuel isn't behaving itself. My setup was running 60 Lb. Mototrons into the 90's with no voltage booster. We didn't monitor fuel pressure per se, but you can fill in the blanks. We were commanding 10.5 to get 11.5, which is actually a tad richer than I would like to be, but didn't feel comfortable without a large safety margin.

My new fuel system will be a return type with a 110 GPH / 12 Volt pump. Hopefully, this will be stable enough to use EFI Live's auto tune to make quick work of the VE tables. It only works when you can get actual to equal CMD AFR. I believe HPT has something similar if you're using onboard WBO2.
 
1 - 9 of 9 Posts
Top