172 Cup engine flat below 4k???

[MeEsH]

I have very recently brought a 172 Cup and im very pleased with it, although im wondering if all 172s seem to have average acceleration up to around 4.5k and then it gets very loud and pulls very hard to to the redline? I enjoy power delivery but is wasnt what is was expecting and thiught I would ask if its the norm.

Thanx in advance

 

[rich-6]

my 182s the same wouldnt call it flat though, except its after 5k then it goes bonkers, Keep the engines high in the Revs on a B road and theyre fantastic i had to completely change my driving style from my last car, I'd enter a corner in third normally and its
2nd in the Clio

 

[Da]

It's the VVT which kicks in above 4.5/5K revs. Quite normal.

 

[bmh.01]

It's the VVT which kicks in above 4.5/5K revs. Quite normal.

its not! VVT is engaged from 1800rpm-6800rpm. Cam profile gives the 5k "kick".

To the o/p just how they are, its normal

 

[Martin_172]

mine does it too but ive fitted the VTEC yo

 

[mattjk]

Bmh or some other clever bugger please explain why the variable vavle system isnt operated on engine startup and why it only comes on once the coolant temp reaches a certain temp? (i think)

 

[bmh.01]

Bmh or some other clever bugger please explain why the variable vavle system isnt operated on engine startup and why it only comes on once the coolant temp reaches a certain temp? (i think)

Its linked with the lower limiter so you don't thrash it from cold basically. Its not enabled so you don't get the power further up the range so you should let it warm up.

 

[mattjk]

^ It makes it horrible to drive for a few minutes tho as an unwanted side effect

 

[bmh.01]

The first few minutes is mostly due to it running open loop until the lambda warms up and it switches from cold start default values. 85c coolant temp (or whatever the limit is for the VVT/high limiter) doesn't come up until the temp gauge is pretty much at the normal middle position so its still running no VVT and lower limiter for a good ten minutes or so after starting. Mine stops being horrible to drive after a minute or so.

 

[mattjk]

Thanks for the explantion, thats a bit strange because once its got into closed loop I cannot tell a performance difference pre and post normal limiter it seems the same.

 

[Djw John]

It's the VVT which kicks in above 4.5/5K revs. Quite normal.

How can you still think that after being on here since 2004!

Its the cams coming into their optimum zone

 

[MeEsH]

Thanks for you help

 

[Martin_172]

Thanks for the explantion, thats a bit strange because once its got into closed loop I cannot tell a performance difference pre and post normal limiter it seems the same.

its hard to notice a difference only time i notice it is pulling out a junction close to my house, it feels a bit flat if i go for a gap but next junction just down the road its fine!

 

[mattjk]

Hmm odd I'v never really noticed! Ill have to pay more attention in future thanks!

 

[bmh.01]

I can tell exactly when mine starts running closed loop. Its very noticable imo.

 

[ben_p]

I can tell exactly when mine starts running closed loop. Its very noticable imo.

agreed

 

[mattjk]

I can tell exactly when mine starts running closed loop. Its very noticable imo.

I think you misunderstood what I meant lol. I mean I can notice once its gone into closed loop BUT I cannot notice pre/post early limiter if that makes sense

 

[Beef-Mc]

mine does it too but ive fitted the VTEC yo

Knows.

 

[Djw John]

After about a minute or minute and a half my car can go from 30 to 35 on a flat section of road without moving the pedal, thats how noticeable mine is!

 

[bmh.01]

I can tell exactly when mine starts running closed loop. Its very noticable imo.

I think you misunderstood what I meant lol. I mean I can notice once its gone into closed loop BUT I cannot notice pre/post early limiter if that makes sense

There isn't really any difference in driveability but it won't develop full power obviously.

After about a minute or minute and a half my car can go from 30 to 35 on a flat section of road without moving the pedal, thats how noticeable mine is!

Thats exactly what mine does, always does it in the same place if I just get in the car and drive off.

 

[Matteh]

ohhh... this would explain why mine feels slow.. its not warmed up...


fancy!

 

[mattjk]

After about a minute or minute and a half my car can go from 30 to 35 on a flat section of road without moving the pedal, thats how noticeable mine is!

Thats exactly what mine does, always does it in the same place if I just get in the car and drive off.

Yeah noticed that too