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Discussion Starter · #1 ·
hey there ive had my 07 mustang gt for about three weeks now, and it feels like it lacks power at low rpms. under WOT in first gear, it doesnt really pick up until about 3500-4000 rpm. The mods that i am aware of are as follows: CMCV deletes, JTL cold air, stc programmer (supposidly tuned for the cmcv's), steeda underdrives. rear gears are 355's. I am going to get it dyno tuned shortly, but i want a little more gettup off the line. is there a cam or something for down low power, or should i put some 373s under in to get out of the lower rpms faster? all help is apretiated, thanks guys!
 

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The CMDPs will cause low end lose but gain power above 3000rpm. If you have 3.55s then 3.73s would be pointless. It would only be worth it if you went to 4.10s. I think a dyno tune will help you out some. Also most cams you lose low end power.
 

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Discussion Starter · #3 ·
thanks for the advice! i didnt want to go to 4.10s because i didnt know how it would destroy my top end speed. i do some highway driving and i cruise around 80 mph. how much higher do you think my rpms would sit at 80 with 4.10s? any suggestions for mods that would salvage a little of my lower rpm power?
 

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w/ 4.10s you'll be around 2600 rpm or so. I haven't gotten 4.10's yet, but people that have them all say the same thing: your useable top speed isn't affected. yes, the top speed is theoretically reduced, but the aerodynamics of this car limit it from reaching super high speeds anyway.
 

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Discussion Starter · #5 ·
i always though the same thing, because my car will reach top speed in fourth gear (due to wind resistance), but my friend with 4.10s said his engine was raoring just to keep highway speed. if anyone has 4.10s please let me know what you think of them. thanks!
 

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i always though the same thing, because my car will reach top speed in fourth gear (due to wind resistance), but my friend with 4.10s said his engine was raoring just to keep highway speed. if anyone has 4.10s please let me know what you think of them. thanks!
I'm curious about this as well. I have the stock 355s and it really feels like a slug down low. I swear my previous 6-er with 373s picked up faster off the line (but lost out in the long run, obviously)
 

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Discussion Starter · #7 ·
I'm curious about this as well. I have the stock 355s and it really feels like a slug down low. I swear my previous 6-er with 373s picked up faster off the line (but lost out in the long run, obviously)
exactly. i had a 99 gt dead stock and i think off the line it would walk on this car. but like i said after about 3500 she really throws you in the seat. i guess im gonna shoot for the 4.10s since there only like 140 bucks on ebay
 

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thanks for the advice! i didnt want to go to 4.10s because i didnt know how it would destroy my top end speed. i do some highway driving and i cruise around 80 mph. how much higher do you think my rpms would sit at 80 with 4.10s? any suggestions for mods that would salvage a little of my lower rpm power?
Go here an calculate it yourself so you know for sure. Tire size has EVERYTHING to do with what RPM you cruise at. Use .68 for the trans ratio:
MOTOR - A Rear Axle Calculator

w/ 4.10s you'll be around 2600 rpm or so.
You can't know that without his tire height.:nono::D:winks

For example if he has:

26" tall tires 75mph is 2700rpm

27" tall tires 75mph is 2600rpm

28" tall tires 75mph is 2500rpm

My 2007 runs at 2400rpm at 80mph. That is spinning plenty high for my tastes.:bigthumbsup
 

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My car came stock with 3.55 that were promptly replaced with 4.10s. It is about 2500rpm at 80mph in 5th gear. The 4.10s are perfect and help get the car into the meat of the powerband much quicker.
 

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My car came stock with 3.55 that were promptly replaced with 4.10s. It is about 2500rpm at 80mph in 5th gear. The 4.10s are perfect and help get the car into the meat of the powerband much quicker.
Another example of tall tires being a factor. You are running 20’s. If someone running 18’s goes with a 4.10 their cruising speed (and overall gearing) RPM will be quite a bit higher.
 

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Well at MY cruising speed (70 mph) :nono: with my 18" tires i am sitting right at about 2300-2400 RPM running 4.10s.
 

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Well at MY cruising speed (70 mph) :nono: with my 18" tires i am sitting right at about 2300-2400 RPM running 4.10s.
You get run over going 70mph in Michigan.:bigthumbsup
 

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I have 17's (27.5inch I think) and I'm very happy with the 4.10s. I'm usually around 2400rpm for 70ish mph. That said, if I'd had the money for a supercharger, I would have stayed with my 3.31s. :bigthumbsup I was only interested in bang for buck mods.

Oh and the top speed with 27.5 tires and 4.10s with an 0.68 ratio @ 6500rpm would be 190mph. 176mph at 6000rpm. Good luck trying to reach that. Unless you're sqidd or 908ssp :shigrin lol!
 

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You get run over going 70mph in Michigan.:bigthumbsup

Pffft! You get run over going under 150mph in your neck of the woods Sqidd!!!:gringreen
 

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Interesting that you guys say your low end is bad. I think my low end is great and I have the stock 3.55s, Bama 93OCT race tune and 18" rims. At 80 I'm at about 2300 rpm. In my 01GT with 4.10s I was just over 3000rpm at 80 but that car was an automatic. The only problem with 4.10s is first gear is real short on these cars.
 

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I totally disagree about 1st gear being really short with 4.10s. I get to about 30 something miles per hour before it kicks to second:shigrin:winks

Second is like nonexsistent though. It literally takes a second or two and you're kicking to third. :)
 
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