Help!!!!!!!!!!!!!

[JinYiSniper]

Hey Bro

Please help me out!!!!! I'm driving a Civic 2005 (ES5) Auto. I had change my exhaust(supersprint), extractor 4-2-1, re bore my throttle body, open pod with cold air intake n ECU. What do i need to do improve my higher end. So far i can go is 140km/h. After that very hard to push somemore. What should i do.


Thanks

 

[obi_waynne]

Firstly we'll assume you are doing this on a track.

Your hitting the upper end of what your engine/gearbox can handle so there is clearly something wrong here.

You need to be really careful because of the stresses caused.

I would suspect that it is the auto box holding this back. The gearing starts to top out so converting to a stick would help. Would I be right in assuming you have large alloy wheels fitted as well?

 

[pgarner]

Are you definetly working in kmh as this is only around 90mph. my 1.4 civic managed to get 110 mph (175 kph ) on a private road, with only a decat and universal induction kit.

so waynne might be right with the auto box issue

 

[JinYiSniper]

Thank to all bro for reply. Wayne, what do you mean by large alloy wheel.? R u refering to my rim. i'm having 16" rims. what should i do to improve my high end.

 

[obi_waynne]

Yes that is exactly what I mean. Bigger wheels alter the final drive ratio and can reduce your top speed.

 

[unityjon]

Yes that is exactly what I mean. Bigger wheels alter the final drive ratio and can reduce your top speed.

This isnt quite true :embarrest:

bigger circumference alters the drive ratio, bigger wheels makes little difference (only weight) if they're fitted with smaller tyres, any good wheel tyre specialist should try their best to keep the overall circumference as close to original as possible when offering and fitting wheels and tyres ! as an example i run 18" alloys on my accord but the tyres are 35profile so if you stand one next to the original 14" (?) wheel fitted with a 60 profile tyre its almost the same size. A lot less tyre but a lot more wheel :bigsmile:

I reckon your main problem is the 4-2-1 manifold that is choking your engine down, you may benefit slightly from a 4 -1 tubular manifold that has decent scavenging properties but is designed for your engine but that will kill low end power as a sacrifice for top end improvement.

The final drive in the Auto box is (like Wayne suggested) probably a factor for your top end too.

 

[obi_waynne]

Fair Do Unityjon - I will be a little clearer next time.

I'd be curious to see if it was running lean.

 

[prevtec]

Yes that is exactly what I mean. Bigger wheels alter the final drive ratio and can reduce your top speed.

yes bigger wheels will reduce your speed,the reason is common sense,it takes a bigger wheel to complete a full rotation than a small one.it might say on the clock your doing a 100 mph[remember this car was set up in the factory with 15 inch wheels on it]but you really are doing less than a 1oo mph with bigger wheels.the same is reversed with smaller wheels maybe thats why you feel the car is slow.if its a show car you want,feck it,get 20 inch wheels for all i care,but if your like me and want performance and speed,dont touch the size off the alloys.honda spend millions a year researching their cars,and if they set a car up with a certain wheel size,you shouldnt modify it,

 

[obi_waynne]

Bigger wheels with tyres that have a larger overall circumference to be exact

 

[AutoCustomEng]

Right forget the wheels,

Let say you want more speed ? you are losing top end, Two things i would do straight away before even going any further,

Change the box to a manual, two reasons, 5 forward gears i reverse, auto 4 forward gears!!! another gear more top end, Secondly and only once you have done that and are not happy is change the diff ratio, However do not forget that if you change the diff ratio you will lose acceleration but you should not if you change the box, you should in fact gain.

It is a lot of work to change the box admittely however it will all be bolt on including clutch etc as honda are efficent,

 

[JinYiSniper]

Thanks to all bro for your reply. I consider about it. THanks