VHPD bhp - emerald

[mcerbm]

I have just had my car (VHPD - Superlight R) on a dyno to see what it produces as I was thinking of going down the emerald / vernier cams route.

 

The car has a cat on (need to keep this on for hill climbs and sprints - regulations) and a raceco exhaust and the fuel was BP ultimate (97 Ron) the ecu is a mems unit.

 

The car made 160bhp @ the wheels which equated to 188bhp at the flywheel. This backed up another run I did a year previous on a different rolling road (159 bhp @ wheels).

 

I was quite pleased with the output as I knew of the 175 / 180bhp VHPD engines mentioned on here. My max bhp was at 7979rpm just as the limiter calls time, this is a it high no?

 

If I go for an emerald and vernier cams would my 188bhp standard engine be more likely to give a better result with the described mods than say a 180bhp starting point VHPD with the same mods?

[Mankee]

When you say vernier cams, you mean vernier pulleys, right? With Emerald and verniers, you are just making the best use of what you have by being able to correctly time the cams and set the fuelling and ignition.

 

There's some information on DVA Power's site regarding standard VHPD engines:

 

http://www.s262612653.websitehome.co.uk/#VHPDkit

[Stuart Miller 7]

You've done well to get 188BHP from a standard VHPD!

 

My SLR with VHPD (on the emerald) made 178BHP and 125Lbfoot on the rollers (that's sub 150 at the wheels) and a friend of mine made low 170's.

 

The biggest difference with the change to Emerald ECU was mid range - and this was a huge difference to driveability. The fueling was all over the place throughout the mid range and top end was massively over-fuelled with the standard Mems. You might want to think about injectors instead of Verniers if budget is a consideration. 178BHP on the emerald is with the injectors running at 100% delivery.

 

The car now makes almost 190BHP and 147Lbfoot after re-build, up-rated injectors, coil packs etc. I still use the standard PTP throttle bodies. Limiter is at 7850 and iginition knocked off at top end. I wouldn't run above 8000 on a standard engine.

 

Stuart

[Mr Happy]

Stuart

 

I guess thats 190 bhp at the wheels?

[Stuart Miller 7]

That's right Mr Nelson.......

 

About 300 at the flywheel... OH those transmission losses

 

Back in your box! 😬

 

Stu

[SLR No.77]

Quoting Stuart Miller 7: 

You might want to think about injectors instead of Verniers if budget is a consideration. 178BHP on the emerald is with the injectors running at 100% delivery.

 

My rebuilt 1900K with mildly ported vhpd head, vhpd cams and running RBTBs made 222bhp @ 7350rpm (flywheel) and 167lbs @ 5900rpm ..... with standard straw colour injectors.

 

Stu.

[Englishmaninwales]

Stuart

I got the same as Stu Forshaw,(1800 k ported VHPD head and cams, Jenvys, Emerald made 220bhp and 161 lb ft on Emeralds rollers) with the same injectors.

Malcolm

[SLR No.77]

Malcolm that's a good result for 1800cc According to the rolling road I used mine could have gone higher but I'd decided on my rpm limit they kindly stuck to it

 

Stu.

 

Edited by - sforshaw on 5 Nov 2012 10:24:37

[Stuart Miller 7]

My original injectors were green or black from memory. Now I have straw coloured ones. Perhaps my originals weren't "original"?? No head work and butterfly TB's. Don't think I'd get 220 in a million years without some serious work.

 

Stu

[Jason Plato]

on an unported vhpd head with 1227 cams on 1600cc I had 210bhp.

 

 

[Mankee]

What do the "straw" injectors top out at? Think they are Rover/Caterham part MJY 100430, Bosch 0280 150 749, 227cc/min @ 3 bar.

[mcerbm]

My dilemma is, apart from the driveability issues, which I know the emerald completely resolves, am I wise to start playing with the cam timing / ECU if the engine is relatively strong?

 

Or does the fact it makes 188bhp in standard setup make it more likely to produce an increase if it were timed properly? I.e. it's a good base to improve from?

 

Thanks for the comments so far

[SLR No.77]

Setting the engine up properly will give you the "best" power and torque across the whole rev range of the car .... ultimate power might be more, less or the same but does that really matter?

 

Stu.

[mcerbm]

If I spend approx 1k and ultimate power is less then I think it would be hard not to feel a bit of disappointment ☹️

 

If the cam cover is off is there any other cost effective upgrades I should do at the same time? I'm not looking for anything too excessive (bhp or cost), maybe a round 200bhp would suit. I don't want to take it much higher or I presume other areas of the engine would need attention.

[oilyhands]

I would sooner have another 10 lb/ft from 4000 to 7500 than 2 BHP at peak.

 

Peak BHP is for bar boasting, a full torque curve is much more useful on the road and the car will be more drivable and considerably faster.

 

Oily