More power for a 1.8 vvc

[Jack MLE]

Hello

 

I own a Caterham powered by the famous and very good 1.8 VVC engine.

I am looking to improve it's performance and i am thinking of replacing the throttle body by the X-Power one and installed an Icon by Superships to help the ECU.

 

Is there any other mod i can do while keeping the VVC trickery?

 

Jack

[Rob Walker]

I doubt you`ll gain much probably not worth the trouble and expense. You could fit a better exhaust say 4:2;1 and lighten the car where possible. Until someone comes up with a reprogrammable ECU that will run the VVC mech you will be struggling, Emerald are working on an ECU but when it will be available is not known.

[oilyhands]

I'd second what Rob says but add that it is possible to squeeze some more power out by porting the head and fitting a better exhaust cam, but the results WRT to bang per buck will likely be pretty meagre. Lifting / stripping re-assembling and re-fitting a VVC head is not for the fainthearted.

 

IME piggy back devices such as the ICON appear to do nothing at all, mostly they just alter the timing a little but since they only splice into the coil signal and not the throttle postion sensor or MAP sensor they are unaware of engine load which makes their contribution limited at best.

 

Oily

[Jack MLE]

Cheers Rob Cheers Oily

 

Thank for the information.

I won'yt install the Icon if it's not good. But I will wait for Emerald to finish their ECU. Do you know the url for Emerald?

 

What about a bigger throttle body? will this give me few more BHP?

 

Jack

[Bob Corb]

A few yes, perhaps 4BHP from the large throttle.

 

Another trick with VVCs is to raise the compression ratio to 10.8:1. This can be done by either skimming the head down or fitting later MGF / TF 160 pistons. These are stronger than the std ones so improve reliability at the same time. They reduce the clearance height and improve combustion whilst also optimising the ignition timing as the Rover engines are always mapped at 10.8:1. As std they are about 10.4:1 mostly. Out of the factory the variation in CR from 10.3 to 10.8 results in a variation in power from 140 to 150BHP (ish). This is partly why the 160 engine produces more power (combined effect of large throttle, high CR and low back press exhaust 143 to 158BHP)

 

BC

[oilyhands]

Improvements in the machining around the combustion chamber on the later VVC heads are also partly responsible for its better output, part and parcel of any porting exerices would be to raise the CR to around 11.0:1.

 

The URL for Emerald is here

 

Oily

[puremalt]

Get a X flow and experience 150 Bhp no problem!

 

Dave Robertson

[markb905]

Jack & MLE

 

Oh dear another VVC owner with the same problem as me!, i have currently gone through most of the options,

 

keeping all the VVC bits, minister power upgrade £2350 fitted, they claim 165bhp,

 

QED do a kit that fixes the VVC position and adds TB about £1500 ish plus vat and fitting, gives 160, they also do other kits which dump all the VVC bits, solid cams DTA ECU TB's kit is £1880 + vat and fitting, gives 175-180 bhp.

 

Roger King was very helpfull cost will depend on what you want

 

So what i am going to do, not sure yet, the minister option which is similar to what Bob as suggested may be the route i will go down, and could give 165-170 with a 4-2-1 exhaust so that will put the minister cost at about £3k!. I am currently thinking of asking QED for prices on the same work as minister,

 

My other option is, upgrade the breaks, widetrack, apollo tank and leave the engine alone, untill i have the £4-5k to do a serious bit of work on the engine

 

And the other option was to fit a 6 speed box, with my 14 wheels and 3.92 dif, which gives similar gear ratios to the SL with 13 inch wheels and 3.62 dif

 

I would be intrested in Bob's view of the "on road" benifits of bigger TB, gas flowing, exhaust etc,

 

Not sure this helps!( not sure it's helped me yet)

 

Mark Bennett

 

 

 

Edited by - markb905 on 27 Jun 2002 20:50:39

[Jack MLE]

Cheers Guys for all the infos

 

Bob,

Do you know a good place where i could get the new pistons? And the part number?

Will a new head will fit on a old block?

 

My technical vocabulary being limited i'd like to know what "porting" exatly mean

 

 

Thanks again

 

jack

[oilyhands]

If you are going to the not inconsiderable trouble of changing your pistons (which honestly isnt required at this level) it would be sensible to fit good quality forged pistons from either Accralite or Omega, these will raise the CR and will also take any abuse hurled at them now, or in future if you wish to raise the stakes , Forged pistons are good for 8500-9000 and 250BHP, fit and forget.

 

Heads on the K series are pretty much interchangeable, the only caveat being that the 1.4K has too small a bore to accomodate the larger valves of the VHPD and VVC heads.

 

Porting is the process of reshaping the ports, valve throats and combustion chambers (and sometimes valves) to improve the airflow through the cylinder head. VVC heads particularly suffer from production anomalies which disrupt airflow through critical parts of the ports which lowers volumetric efficiency and hence power output. Porting the head will remove these anomalies and further improve the airflow through the head. Quite often this is erroneously referred to as 'polishing' and a polished finish is not what is required, its the *shape* that counts.

 

I have a pile of 9 VVC heads here which I have just finished porting and 2 VHPD ones still underway, the condition ex-factory of most of the VVC heads was awful with the valve seat inserts recessed by up to .75mm and misalignements of up to .5mm between the ports and valve throats. This is one reason why some engine produce more horsepower than others, measured airflow through these heads can be up to 40% different at low valve lift and 10% at maximum lift.

 

Oily

 

Edited by - oilyhands on 28 Jun 2002 09:44:29