when i first got the 7, i remember running 140mph or more on it. Now, after some mods (Bonez intake, Apex'i GT Spec exhaust and Koyo Radiator), i can only top at 110 mph.

The question is, WTF did i do wrong? how in the heck with those mods i would lose 30mph?

 

I don't know. but that DEFINITELY isn't right for a s5 n/a. pre-mods, you should do at least 137, if I remember correctly. I don't know what the problem would be, though.

 

You said you did an exhaust system.

Are you sure your 5th and 6th ports are opening? I'm wondering if that could be it right there.

How does the performance of the car feel overall?

 

Sounds like your 5&6 ports are stuck in the close position; I had this issue once, where the vac line that connects the 5&6 ports to the electric solenoid was disconnected.

 

My S4 NA tops out at 125 with intake and exhaust. Err... or maybe i just keep running out of bridge

Definitely check your ports and VDI and make sure they are opening when the solenoid turns on.

 

my car does that in 3rd gear

 

V8 swaps don't count

 

V6 =D

Does sound like the 5th and 6th.
Check your vac hoses.
If not vac hoses, you're probably going to end up pulling those out, and I would put the Pineapple racing inserts into the sleeves, and just have the ports open all the time. The loss in low end torque isnt a big deal - I've never met anyone who starts from a crawl when they are racing. Usually you rev up to 3k on a RWD and slip the clutch.
You never have to worry about 5th and 6th activation again!

 

Personally I'm not patient or brave enough to wait for my FC to get above 120... although I'm sure it could... Hell, it could go for 60 to 120 in 5th if I just floor it long enough (about a minute...lol).

that, and I need a radar detector... I'd like to keep my zero traffic stop record... and avoid vehicle related felonies.

 

Tickets aren't worth it.

 

i did 145 in my s4 n/a. headers cat back and intake.

 

Do you have a picture of these headers?

 

+1

 

My 7 maxes out at 80. Because I'm not insane.

 

I've hit 100 in my 7 but my tires were so horribly off balance it felt like i was driving through Arkansas (you know what i mean if you've been ther :p)....that and I can't afford no more stops after 4 speeding tickets and a reckless driving ticket...

 

+1, but maybe 85..... Driving that fast on public roads is stupid. I don't care if you die.. but the innocent person you crash into doesn't have to.

Take it to the track.

 

tire set up? maybe you had smaller tires back then and have taller tires right now?

 

well, the thing is of course i dont run all out in a public street. there's a strip down here where i'm from that is in a private property (or should i say GOVERNMENT PROPERTY) that's open and that's where I let off and just run my car (an abandoned municipal airport). Maybe, like what others said, it's my 5th-6th ports. i haven't checked them, but i know they work, coz at 3500 and 5500 i feel the car putting some boost, or am i mistaken?

as for the tires... i had 14's then, now i have 17's... but would it make THAT much of a difference?

 

its an NA. those things shouldnt go over 60.


j/p. i had those same mods to my old s4na. down to a T. cept i had N1.

 

Do the Air Pump and the ACV control the 5th and 6th port actuators on the n/a s4? I'm thinking about ditching my ACV and A/P.

 

Awww you NA guys are so cute...120, 130, 140. <----thats cute. lol. Just kidding but I agree, it sounds like your 5th and 6th ports.

 

My S4 N/A tops out at 125mph or so. Just the mods the last owner did (sig), which aren't worth anything. 125mph is also about what the S4's rated top speed is. You should probably check your 5th and 6th ports too. They'll make you lose about the same as what a new exhaust gives you.

Sigh... still saving up for a new suspension. Then comes the exhaust. As soon as I get some free time I'll build a cold air box. Hopefully things will go faster now that I'm out of school. And I'll be working again soon.

 

My 7 top out at 145 mph.and had more coming but i ran out of road and had to slow down. I only have cold air intake and a full exhaust. And it only has 28,000 mi. on it

 

Yeah... that's impossible. 3rd gear's ratio is such that you can only hit around 90 in it, at least in an S4 N/A. I can see MAYBE 100 depending on where you shift.

 

my stock 89 auto non-turbo tops out just under 110 on clean 12 lane highway
and at about 3.5K RPM at that speed it feels like a golf cart heh

and since no one seems to have taken a stab at the massive size change in tires

well DUH. you really think you can go 3" difference on tires w/o causing massive changes to the way the car works. lol!!!!

where were you during middle school filmstrips in science class lmao