Why do I need to launch @ a higher RPM???
 

Since my last install (TFS intake, MAF(30#), TB, FP, 30# inj) I seem to have to launch at a higher RPM......and if I don't the car bogs on me. Why would this be happening? Could my idle be too low? Timing?

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'90 LX 5.0; 12K original miles (no sh*&); 3.55 gears; pulleys;Edelbrock Performer Heads; BBK shorties; MSD 6AL box w/ blaster 2 coil; Motorsport E303 cam; Pro-M 75mm MAF; BBK 70mm TB; Eibach spring kit; Southside welded subs; K&N cone filter charger; Hurst shifter; fiberglass turbo hood; A/C-less; rear seat-less; cat-less; 2 chamber Flos; Corbeau racing seats (fronts);
30# injectors; JMS Chip; 190 lb fp; TFS track heat Intake (12.299 @ 113)

The big throttle body, mig MAF meter, and intake with bigger runners may have moved the powerband up a little, and it's not agreeing with your 3.55 gears. Just a thought..

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93 Coupe, long tubes, pro chamber, flowmasters, 3.73, auburn, alum driveshft, subframes, tri-ax, pulley, 73mm MAF, cobra Rs.

That pretty much sums it up, your powerband is higher and you've outgrown the 355's. Also, at what RPM are you crossing the stripe in?

I used to launch at 2500.....now I have to leave at 3500-4000. So, now that we seem to have figured that out......keeping in mind I'm gonna be blowing next year......should I bother going to 3.73's??? Thanks again!

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'90 LX 5.0; 12K original miles (no sh*&); 3.55 gears; pulleys;Edelbrock Performer Heads; BBK shorties; MSD 6AL box w/ blaster 2 coil; Motorsport E303 cam; Pro-M 75mm MAF; BBK 70mm TB; Eibach spring kit; Southside welded subs; K&N cone filter charger; Hurst shifter; fiberglass turbo hood; A/C-less; rear seat-less; cat-less; 2 chamber Flos; Corbeau racing seats (fronts);
30# injectors; JMS Chip; 190 lb fp; TFS track heat Intake (12.299 @ 113)

ive always wanted to hear an opinion on gears from someone has them and uses them at the track. my friend just finihsed his 351 w combo and let me tell you something, those 3.73 gears are way too much for a fox body and t5 tranny. (unless you have some REAL sticky tires) yesterday at carlsbad track we were having a hard time keeping the tires down with ET streets. the car was runing 13 flat due to the tire spin.

if you are planing to stay street, stay with the 3.55s
just my opinion.

I have 3.73's and had to switch to 28" tall drag radials because I was running out of motor at the end of the track.

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1988 Mustang GT
12.0 @ 122
1992 BadAzz Wrangler
1993 Explorer

Stick w/ the 3.55's even though I can't lay down the rubber in 3rd and 4th anymore after my last mods?

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'90 LX 5.0; 12K original miles (no sh*&); 3.55 gears; pulleys;Edelbrock Performer Heads; BBK shorties; MSD 6AL box w/ blaster 2 coil; Motorsport E303 cam; Pro-M 75mm MAF; BBK 70mm TB; Eibach spring kit; Southside welded subs; K&N cone filter charger; Hurst shifter; fiberglass turbo hood; A/C-less; rear seat-less; cat-less; 2 chamber Flos; Corbeau racing seats (fronts);
30# injectors; JMS Chip; 190 lb fp; TFS track heat Intake (12.299 @ 113)

The best thing to do is take the car to a dyno and see where your powerband is. You should be able to better gauge what gears to get from that info.

Did you get your chip reprogrammed after the changes? If not, that may be a big part of it. If it's optimized for car the way it was and not the way it is now, you could be losing a lot of power.

What do you think of your Corbeau seats? Are they fixed or can they recline? Do you have pictures? At some point I really need to buy new seats. E-mail me so we don't disrupt this thread if you don't mind. Thanks.

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351W 89 Mustang GT Convertible