Hi,

I tried doing a search but could not find exactly the answer I am looking for...

Currently, my late 04 MCS, has the Alta 15% pulley, GIAC map and one-ball exhaust. My car feels good from 1st up to 4th, but seems to lose alot through 5th. Now my question is, will bigger injectors help with this? Like JCW or similar...

Thanks in advance guys..

Regards
Esham

 

No. You should look into getting an RMW retune of your ECU to get more torque and power out of your current mods. Larger injectors in your case are not a limiting factor. Try to contact Jan at RMW and find out how you can get a retune. Then power in 5th and 6th gears will not be a problem.

 

What's your shift point for each gear?

 

I change around 7000rpm...

 

there is a noticeable difference between GIAC and a custom tune. Besides Jan, you could go see LDG in Maryland.

 

Thats gonna kinda hard seeing that I'm from South Africa...

 

i also have a similar problem, i'm from the philippines and the only tuning options that are available here are:

1. ECU remap/reflash (chip on a dynapack)
2. S-AFC tuning

 

You are waiting far too long to shift.

Redline is about 6800 rpm so even with a higher rev limit you aren't as efficient delivering torque since the curve for that has likely peaked at about 4000-5000 rpm then drops off from there.

Better to shift by 4500 to 5000 rpm and don't worry about 5th and 6th gears which are too tall anyway unless you are driving at 90 mph or similar.

On the track I only use up to 4th gear on the longest straight with top speeds of about 105 mph and it's fine, no where near the rev limit.

Since you don't live nearby you have options-
If you ever travel to the US then you can remove your ECU and bring it with you in your luggage and have one of the tuners- LDG or RMW do a retune for your upgrades. That will help.

Next- what wheels and tires do you have now? If you have heavy wheels and street tires you might be able to improve performance quite a bit with lighter wheels, smaller tire diameter tire sizes and some Max or Extreme Performance summer tires.

 

You didn't mention anything about a cold air intake. With a pulley, your engine may need more air. Consider a CAI?

 

@minihune - I'll try that. But changing at 4500 to 5000 rpm seems very low as my car does feel that it makes power beyond that. I am currently running 18" MCS GP wheels..Thanks!

@beken - I actually forgot to mention my CAI.. I just attached a cone filter to the OEM pipe and had it boxed off. Also cut a hole in the cowl...

Thanks for the help guys!

 

OK, the Horsepower curve starts low at 2000-3000 rpm and steadily climbs up to about 6500 rpm which is what you are mostly feeling. Torque curve builds quickly from 2000 to 4000 rpm then levels off from 4000 to 5000 rpm. From about 5200 rpm to redline torque falls off by about 20 ft-lbs down to the level of about 2500 rpm.

This means your usable power range is up through about 5500 rpm so shift at about 5000-5500 rpm is about right for best power. 5th and 6th gears are going to be taller so no real need for those as much unless you have a long track with much higher speeds.

18" GP wheels are good considering how big they are. For now keep the wheels.

Which tires do you have?

205/40-18 tire diameter 24.4"
215/35-18 tire diameter 24"
225/35-18 tire diameter 24.2"

Some example tires-
Max Performance Summer tires-
Michelin Pilot Sport PS2 220 treadwear
Comes in 215/35 and 225/35-18 for $206 and $246 respectively
Goodyear Eagle F1 GSD3 $198 each 280 treadwear 225/35-18
Pirelli PZero Nero $194 each 220 treadwear 225/35-18 and many sizes