decat...help...lost power

[viceroy]

Hi all,

A while ago I decatted my mk1 172 and noticed that the car was noticably better at highway speeds, and just seemed to pick up better from lower in the rev range.

I also have been doing better drag times (-0.2s) with higher terminal speeds (+4km/h), and have really improved my lap times on the track (-1.5s)

Yesterday I had thr car on the dyno and made 28kW less and 38Nm less than normal, but my low and midrange torque was up giving me quite a flattish torque curve from 1500rpm all the way through to 6500rpm

My torque figures look a bit like this (all figures are at the flywheel corrected to sealevel)

1500rpm - 152Nm
2000rpm - 137Nm
2500rpm - 138Nm
3000rpm - 158Nm
3500rpm - 161Nm
4000rpm - 152Nm
4500rpm - 158Nm
5000rpm - 168Nm
5500rpm - 173Nm
6000rpm - 167Nm
6500rpm - 152Nm
7000rpm - 123Nm

Could the engine be running lean because of the decat? which has taken my peak power and torque away?

Im taking the car to be chipped either this week or next week to try sort out the problem

 

[JAY172]

i can remember somebody else saying a decat on there 172 had improved mid range power but peak power was done a bit.

 

[cliosportcraig]

Yeah if you mess with breathing mods without compensating the fueling then you get a messed up mix !! Get it chipped !!

 

[Lunner]

When i stuck the de-cat on mine cant really say it has decreased power but it has more mid-range power.

Maybe something to do wiht the fact the the eigine needs something to push agaisnt, try fitting a valve to the exhaust

 

[cliosportcraig]

Quote: Originally posted by Lunner on 01 March 2004


When i stuck the de-cat on mine cant really say it has decreased power but it has more mid-range power.

Maybe something to do wiht the fact the the eigine needs something to push agaisnt, try fitting a valve to the exhaust

huh ?

It dont need to push against anything mate !! You wanna push the exhaust gasses out as fast as possible !! It the fueling which is wrong mate !! A hillpower chip should sort it !!

 

[JAY172]

think it was ryhs who mentioned it before.

 

[BenR]

only way to find out is to alter a factor and test again,.

 

[viceroy]

Well Ive since started thinking that having the car sitting in the sun (30 C / 35% humidity) with the engine running, and the fac the car is a dark colour really couldnt have helped my result any, so Im gonna take the car to the same dyno one night this week to check again before we install the chip