superchips ICON & VVC

[markb905]

Has anyone fitted or got a veiw on fitting and icon race unit to the vvc,

 

 

 

Mark Bennett

R500MB

[Bob Corb]

These Icon units are a bit cowboy etc. There is a little benefit from advancing the ignition a couple of degrees on a VVC but the same effect can be achieved by fitting the MGF Trophy ECU (NNN000100, £200). This will be properly calibrated rather than a bodge. If you are after a mild performance upgrade on the VVC do the following.

 

1. Port the head slightly to match the valve seats into the ports and smooth the join from the inlet manifold to the head. Also while the head is off get it skimmed to raise the compression ratio to 10.8:1. An alternative is to fit high compression pistons which are a bit stronger (I haven't tracked them down yet)

 

2. Fit a new larger throttle (MHB000261, £98) from the MGF Trophy 160.

 

3. Junk the cat if you have one.

 

A healthy VVC engine with the above mods should make nearly 170BHP.

 

Cheers

 

Bob

 

 

[DaveK]

Bob

 

Apparently QED can do high compression pistons to suitwhich take the compression up to 11.1.

I'm looking at tuning a VVC Elise so your info and part nos are very welcome.

Do you know what the changes were to the mgf trophy 160 engine over the original 143 bhp VVC engine?

 

Thanks

 

 

Dave

[oilyhands]

170BHP might be a little optomistic, Ministers claims for these mods are 160BHP and when pressed they concede it might be a bit less. The 160 has some modification to the valve seat and throat area (factory done, I've got one on the porting bench at the moment) a larger TB, and revised manifolding and calibration. The best I've seen for simple mods on an otherwise stock VVC is 165BHP, that was a seriously ported head, larger TB and better exhaust manifold.

 

In addition to the port work, the combustion chamber requires reworking to remove the recession of the seat inserts, this a serious production problem that was prevalent on the VVC and prevents much air flowing until the valves have lifted .5mm or so, this effectively shortens the cams duration by 10 degrees and at the vital point in the cycle where scavenging occurs.

 

There is also some scope on the VVC for a bit more duration on the exhaust cam which is quite mild, the K is very sensitive to exhaust cam timing, another 10 degrees or so of duration on the exhaust cam could bring up the torque quite a bit. Piper can re-profile the VVC exhaust cam to suit.

 

I have been present during back to back tests with the ICON and similar piggy-back devices, some of which are unaware of throttle position and hence can only alter timing across the board for any given engine speed. After several successive runs with and without these devices we could see no measurable difference between the runs.

 

Oily

 

Edited by - oilyhands on 3 Feb 2002 00:09:47

[markb905]

Bob, Dave Oily

 

Thanks all for the information, I have thought about the MGF Trophy, up grades but wasn't sure what effect that would have, but £300 for the ECU and larger throttle body has got to be better than £250 for the icon unit!, I'm not to interested in getting into any serous work with the engine as I am planning on going, for a superlight r in the next couple of years and don't want to do anything that might affect the ease of resale. So any thing that gets the most out of what I've got is the main plan.

 

Would the MGF Trophy ECU be of any real benefit without doing the rest of the work you've suggested?

 

this is the first time I have posted any questions on the net, and if all the replies I get are as helpful, I'm on to a winner. I'm sure you have all experimented with different fuels, but I've been using the new Shell OMTIMAX which does seem to make a difference, worth a try if you haven't already

 

no more "’" !!

 

Mark

 

 

Edited by - markb905 on 4 Feb 2002 18:54:12

[markb905]

I have no idea where the "’" came from but it should be a '..

 

Mark

[oilyhands]

It's likely that the stock ECU will cope with ther bigger TB.. try it and see, if you have a problem with leaning off, then you could then try the Trophy ECU...

 

DaveK.. I've tried replying to your email, but your ISP has bounced my reply...

 

The forged pistons QED supply are an expensive way of gaining the extra compression, good though they are..

 

Oily

 

Edited by - oilyhands on 3 Feb 2002 13:11:22

[markb905]

Oily

that certainly seems the logical way to do it, but excuse the daft question but how would i tell if the car was running lean?

 

Mark

[oilyhands]

Aprt from the subjective ways.. hesitancy and flat spots, the *best* way is a lambda or CO probe on a rolling road... Emerald can probably run it up and put it under load while measuring the AF ratio. It would be useful to do this anyway pre and post modification to see what affect the mods have had.

 

Oily

[tony isherwood]

I have no idea where the "’" came from but it should be a '..

 

cause if you edit in Msoft word to get the spelling correct, and paste it into the L7C message space it does that. No idea why !

[Bob Corb]

A stock ecu should cope with the larger throttle body. The engine management will simply see higher pressure in the the inlet manifold and compensate accordingly. Its going to feel like a new air filter on a day with high barometric pressure.

 

The trophy ECU will also make a little difference on its own. Just dont expect to feel much.

 

BC

[markb905]

Thanks all for the replies, i think i will have a go with the larger throttle body first and see what happens. However I can see form what you've suggested that without to much modification I should get 10-15bhp gain on top of the 150 it should produce, the other point is that the modifications are more about getting the best out of the vvc as it stands and not, binning the vvc & fitting direct to head TB';s, DTA ECU as was suggested to me by QED, which I'm sure would have done the trick, but not really in the way i was intending

 

now all I need to do is find the right people to do the work and start planning what to get done after the TB replacement,

 

Thanks

Mark

 

 

Edited by - markb905 on 4 Feb 2002 18:56:17

[Bob Corb]

Piper cams are looking into regrinding the inlet cams of the VVC, I dont know what the effect would be. It sounds like it could boost top end at the expense of idle quality and low end torque. Wait and see.

[oilyhands]

I've had a chat with Warren and John at Piper about that, following some lengthy discussions with an unnamable source within Rover. It's likely that too much extra lift and/or valve acceleration / duration might well lead to the premature death of the VVC units.. not a trivial problem..

 

However there may be some scope to improve the exhaust profile.

 

Oily