Vhpd Over Fuelling

[russelld]

My Sport 190 which has a K series VHPD and lotus UCU runs very rich

 

The exhaust exit pies are sooty and the engine oil turns black after about 1,000 miles following an oil change. As I understand Lotus set the ECU to run rich on the VHPD cars as this is far safer than running lean.

 

After reading Phils post about his recent engine mods which include a fuel pressure regulator to increase fuel pressure, it got me thinking would using a FPR to reduce fuel pressure make my car run a little cleaner ?

 

The preffered route to sort out these engines running issues is an Emerald ECU and a set of Verniers to time the cams more accurately, but as times are hard I can't afford to throw £1,500.00 so hoping for a more economical ( Pikey ) solution.

 

My plan is two fold :

 

1) Measure the lift of my cams at TDC to see how far from ideal they are, and then have some offset dowels made to compensate if needed.

2) Fit a FPR with a gauge then have the car Dyno'd to set the fuelling.

 

 

Would this work or am I missing something ?

 

Does anyone know what the lift should be at TDC for VHPD cams ?

 

Can anyone lend me a couple of DTI's to check the valve lift ?

 

Thanks

 

Russ.

[fentuz]

Russ,

 

the FPV is set at 3 bar by default, it you press the throttle, it will increase the pressure thanks to a diaphragm. That pressure can be set up however, I believe it can be set for values above 3.0Bars.

 

I think the best would be to check it the current fuel pressure regulateur is to specification. On a classic K series, it is specified for 3.0 +/-0.2Bar. If this is also the VHPD spec, is the current pressure within spec?

What injector have you got? If you have injectors with a greater debit, you will run rich as they provide more fuel for the same given time.

 

ECU wise, you could get the ECU fitted and mapped now to current spec and when it is time to do the cambelt, you could fit some vernier, time everything and get a "quick remap"

Reading a Seloc thread some time ago, Lumination seems to produce a cheaper ECU alternative although Emerald is really the most straight forward solution.

[russelld]

Thanks Bill,

 

It may be that a programmable ECU is the only way ! I can't afford one at the moment so I'm really just looking to improve things without much of an outlay.

 

Could something like this work instead of a FPR ?

 

http://www.ebay.co.uk/itm/ECU-Master-Digital-Ecu-Tuner-III-MAP-Sensor-400kPa-Piggyback-afc-controller-/300693918122?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4602c111aa

[fentuz]

I don't really trust these things. As I said before, it might be worth checking your fuel pressure first. Could unit 4 check these thing for you?

 

Ecu, have you asked on place like Seloc if there are some issues?

[olliecast]

Ive got a fuel pressure gauge I made up if you wanna check it.

 

In addition, doesnt all oil turn black? Nothing to do with running rich?

 

if you really wanna know then surely install a wideband or get it dynod and probed?

[John FISH Curtis]

install a wideband or get it dynod and probed?

 

 

^^^^^ This.

 

Check to see how its running before shoving loads of money at it.

[scatty]

phone the chaps at area 52 in sutton and ask them to slap it on the rollers and do a test for you....

[Phil S1]

You might be able to go on the rollers immediately after me, I'm booked in for 10.00am on Tuesday Russ.

[Martin R]

Standard VHPD cams. 125 thou inlet and 110 thou exhaust lift @TDC.

[russelld]

A quick update :

 

I phoned Area 52 on Saturday to book the car in for for a diagnostic session on the RR. 2 hours later at 4pm the car was strapped down and all sorts of probes and sensors were attached.

 

 

Here is the graph of power and AFR

 

 

And power torque graph here :

 

 

Now compare this graph to one that was done a couple of years ago at an MLOC shootout at Monster Motorsport in Loughborough :

 

 

 

As you can see power is down 7 BHP and torques are down 17 lb ft at peak

 

The graphs look completely different ! If you look at the Monster graph from 2 years ago there are two distinct spikes in the torque graph one at 3250 rpm and the other at

4400 rpm.

 

Looking at Saturdays graph the spike at 4400 rpm has gone and the spike at 3250 rpm seems to have moved to 3600 rpm.

 

The AFR also does strange things between 3 - 4 K rpm I presume this would have been the case 2 years ago as it mirrors the the first spike.

 

Has anyone any ideas on what may have changed ?

 

Jason at Area 52 says he thinks the AFR is good for power except where it leans out at quickly at 3600 rpm, he can't understand why I'm covering the planet in soot !

 

He plugged into the OBD and it was showing strange readings for the MAP sensor. The reading for this sensor was 67 kilopascals or 0.67 Bar which shows a partial vacuum.

This reading did not change with throttle position as you would expect.

 

So I have a few questions which I hope someone can help with :

 

1) Does anyone know if there is a MAP sensor on the VHPD and if there is where is it located ?

 

2) The engine had a new cam belt about a year ago. Is there any way that this could have affected valve timing and could this explain the missing torques ?

 

Russ.

[Phil S1]

I don't know the answers to your questions Russ but it does seem to be low on torque, or is that normal for a VHPD? Does Martin have a graph for his to compare yours to?

[Martin R]

Im not sure Russ but is the MAP sensor attached to the backplate on the throttle body airbox and pokes through into the airbox? Also take of the cam belt cover and check all the marks line up for 90 BTDC.

 

Edit, I have now worked out how to load my graphs from Area 52. Russ mine has done nearly 50K at this point and according to Roger the head was well worn. Also i had on a standard exhaust manifold. Some of the differences may be down to the Different rolling roads? The dip in the AFR does not go dangerously low and is caused by the cams in a VHPD probably? They are not actually " on cam " till nearly 4K RPM as you know.

 

 

 

[fentuz]

Martin, what did you mean by head was well worn?

[Martin R]

Martin, what did you mean by head was well worn?

 

Bill, the valve guide wear was as bad as Roger had seen on a K series. Also he said the inlet valve seats were virtually all shot. Hence the decision to find a new one Also it had in its life been heavily skimmed. It was repairable but at a cost. I thought long and hard but decided not to spend anymore on it.

[russelld]

Im not sure Russ but is the MAP sensor attached to the backplate on the throttle body airbox and pokes through into the airbox? Also take of the cam belt cover and check all the marks line up for 90 BTDC.

 

 

Martin,

 

I thought that was a temp sensor but I am likely wrong ! If it is a MAP sensor then the reading of .67 Bar is clearly not as it should be. Inside the air box should never be a vacuum, so a MAP sensor here would not give a meaningful reading.

 

I'm off to search the Seloc archives.