Engine re-built but still missing 50 BHP

[Paul White]

My R400 is currently an R300 despite an engine rebuild; it was 150 BHP before and still 150 now

 

The engine has been re-built by DVA Power and Dave has been extremely helpful by checking and double checking everything on his side so the power loss must be somewhere else.

 

There's no apparent misfire and the car drives well (if it was an R300, that is) so I need to look at the other possibilities, i.e. sensors, ECU etc.

 

Does anybody have a R400 MBE that I could swap over for an hour to see if that makes a difference? Or indeed, had any similar experience?

 

 

 

 

 

K80 ROM, metallic green R400

[rj]

How do you know it's missing 50BHP?

 

I have a couple of ECUs - here in Denmark - but they won't be programmed for an R400.

 

Have you checked that your throttle opens completely? Have you had a wideband lambda meter on it to see what it does?

 

Can you email your current map to me?

 

 

[Paul White]

Hi RJ,

 

I put it on the rolling Road after it was slower than I expected on my first track day and It seemed to lose power at 6000 RPM. I was puzzled because my old 8V Vauxhall Caterham, which was 150BHP and 145lb ft of torque was quicker around the same track.

 

After the re-build I did another track day and it felt the same, a dip in power between 6000 and 8000 RPM. When I put it back on the rolling road, the power was still 150 BHP (and only 115 lb ft torque) and the power and torque curves were almost identical.

 

The throttles seem to open fully.

 

The car went to CC at Dartford to see if they could find the problem afterwards and they altered the timing slightly. It now pulls slightly better at the top end but loses some mid range power; it is still 150 BHP though (third trip to the rolling road in the last few months). I would hope that they would have checked lambda sensors etc.. but don't know for sure.

 

I don't have any details on the map I'm afraid.

 

 

K80 ROM, metallic green R400

[rj]

I would be surprised if it was the ECU.

 

Could the exhaust or rather the cat have packed up? Sounds more like something like that to me.

 

I do have a spare cat and a cat bypass 4-1 for a K Rx00, but again I'm in the wrong country.

 

 

When you had the car on the rolling road, how did the mixture look?

 

It could also be your fuel pump which had given up.

 

 

In first case you'd be running rich, in second case lean.

[Paul White]

RJ,

 

The car is exactly the same with all 3 exhaust systems I have (1 with a cat).

 

I don't know about the mixture, as all 3 rolling road sessions were power runs and each time it was so far short that they sent me away again without any analysis!

 

I hadn't considered the fuel pump as it's not an intermittent fault that you might associate with occasional fuel starvation. The car does drive very smoothly, it's just 50 BHP short.

 

Re. the mixture, the plugs look OK but it is only doing about 11MPG even when driven slowly.

 

 

 

 

 

 

Edited by - Paul White on 18 Apr 2010 19:05:37

[Sigmamark]

If I were in your position, I would be inclined to have a trip up to Dave Walker at Emerald. I accept that it will be an expensive trip to Norfolk at 11 mpg and possibly even more so as you may/will end up buying an Emerald ECU, but I don't think many people have left his rolling road without a very clear understanding of exactly what is going on with their engine.

[rj]

It could also be the fuel filter that has packed up.

 

You could try to test the fuel pressure which can be done relatively easily.

[Mark Durrant]

Which rolling road did you use for the power run 🤔

 

Edited by - Muppet on 18 Apr 2010 19:52:08

[Paul White]

Hmmm... I thought about emerald but was trying not to spend too much more on what I am convinced is something silly and simple.

 

2 different rolling roads, but similar graphs and results Steve Greenald, Rainham & Surrey Rolling Road, Chobham

 

K80 ROM, metallic green R400

[Sigmamark]

Give Emerald a ring. It seems such a shame not to have the power output you anticipated and a chat and possible trip up there should solve the whereabouts of your missing power. They managed to find 247 bhp in my K Series motor so what have you got to lose?

[mattobrien]

I had my R500 remapped by the two Steve's at Track n Road - they knew what they were looking doing / looking at and managed to get a much smoother car and 240 bhp. Might be worth booking in for a mapping session with them - they work on most ECU's (mine is a MBE), so you might be able to save the cost of a new one.

 

Good luck

 

Mat

 

 

 

[Panto Si]

Sorry for the hijack, but what did you do to your vx 8 valve to get 150bhp?

Cheers

 

Beaulieu #28

[EFA]

If it runs reasonably smoothly, then it is the map being affected by an external variable (such as fuel pressure, coolant temp etc) or it is something mechanical such as cam timing.

 

I would start with the latter, and also get a leak down test done while you are there.

[Paul White]

lol! stuck a 2.0 l SRi engine in it with a Blydenstein head (later high port version). Still got my old 1800 Supersprint short engine in the Garage if you're interested?

 

K80 ROM, metallic green R400

[Paul White]

Hi Arnie! long time no speak. Never did get round to wrapping your car.

 

We have checked & double checked the cam timing so we can rule that out. I took the car to CC to check all the sensors etc and they changed the Cam timing

 

Can't be bothered to take it back and go through it all again.

 

K80 ROM, metallic green R400