Build update - almost there

[chesterak]

Car driving, at last Rolling road Tuesday night to set up speedo and carb, MOT Wednesday. Still trying to fill in the soddin' SVA application form :angry: Spoke with a vey helpful inspector at Liverpool SVA centre....he told me to ensure I have a nearside mirror fitted as with roll hoops (2) they block more than 10% of the centre mirror.

[chesterak]

Who's a (almost) happy bunny then? :thumb:
Some images from the rolling road session. After some messing around to get the carb set up, we went for a power run. It made 270BHP at the wheels on the second run. What we didn't realise until after the print out was the power fell off quite sharply at about 5500 rpm. This was due to too much advance - the tester reconed about another 10-15BHP would be possible in a usable range of 3000-6500rpm. Anyway, alowing for aprox 20% transmission loss (I'm sure someone will know what is reasonable to estimate as losses) this gives an crankshaft BHP of about 320BHP - not bad for an ol' RV8
It passed the MOT today, still trying to fill out the SVA form :angry:

[David Large]

That is some "ol' RV8" if you think it is doing 320bhp at the flywheel. What have you done to it? What size is it?

[Pim.Cobra]

If it's a manual transmission, then approx. 25% loss is more likely. With an automatic it's 30-35%, depending on the box.
This would mean around 337 bhp at the flywheel.....
I'm very interested in the specs of your "ol' RV8" A friend of mine got some 220 bhp at the wheels with a 4.6, 285 cam and 4 double 45 dell'ortos..... and mine is doing less than that, although it is in very good condition. Perhaps my new setup will improve this; LPG injection, 72mm throttle body, 45 mm trumpets, ported itake, 234 cam. (I already have stage II heads and 45 mm headers....)All planned for next autumn/winter, didn't have the time to install before the beginning of this season.... (I don't drive in the winter season anymore since I ruined a set of wheels due to the amount of salt they use on the road here....)
Very impressive result, I hope to get near!
Cheers,:thumb:
Pim

[chesterak]

Where to start. The basis is a Wildcat 5.0L block - was a porus 4.6, now fitted with top-hat liners and a stroked crank. The cam and lifters are from V8 Developments, as are the heads and 600cfm carb. Cam grind, from memory, is their version of a Piper 285. - I'll confirm this. I port matched everything, inlet and exahusts, and fabricated 1/3/4" headers into Dax sidepipes. The exhaust centres are 2" for SVA, but will be 3" after which should give a little more power. I also have a Jacobs ignition system (Russ Rams recommendation) that produces a spark you can weld with! It also has a billet steel lightened flywheel.

I read with interest previous posts on oil pressure....this has a serpentine front-end, and with running-in oil it was making about 30psi at tickover and about 60 at full chat, red hot.

I think there are a lot of fishy stories regarding power outputs and "dyno" figures. My confidence is the people who carried out this session and the quality of the kit they use - they have no vested interest in what my engine will do - and their approach to problems as they arise was methodical.

I drove the car before set up on their trade plates - I haven't driven anything like this before, to say I'm pleased is an understatement :thumb:

[David Large]

I understand now, your engine is anything but an "ol'RV8".

[chesterak]

David,
You are, of course, correct.
My experience of building/tuning petrol engines is very limited - all learnt on pre-unit 650 Triumph engines. I have even less experience/knowledge of Cobras and I'm trying to learn more.

I was alluding to conversations I've overheard and been party to where your Cobra is not "serious" unless you have some form of American engine - even when they produce less power and weigh twice as much as a good ol' RV8 (not forgetting the Buick ancestor).

Now then, where did I put that do-it-yourself guide to fitting nitrous oxide systems.....

[TonyD]

"Now then, where did I put that do-it-yourself guide to fitting nitrous oxide systems..... "

Fit one of those and you'll be laughing.:thumb:

Cheers,
Tony

[chesterak]

Where to start. The basis is a Wildcat 5.0L block - was a porus 4.6, now fitted with top-hat liners and a stroked crank. The cam and lifters are from V8 Developments, as are the heads and 600cfm carb. Cam grind, from memory, is their version of a Piper 285. - I'll confirm this. I port matched everything, inlet and exahusts, and fabricated 1/3/4" headers into Dax sidepipes. The exhaust centres are 2" for SVA, but will be 3" after which should give a little more power. I also have a Jacobs ignition system (Russ Rams recommendation) that produces a spark you can weld with! It also has a billet steel lightened flywheel.

I read with interest previous posts on oil pressure....this has a serpentine front-end, and with running-in oil it was making about 30psi at tickover and about 60 at full chat, red hot.

I think there are a lot of fishy stories regarding power outputs and "dyno" figures. My confidence is the people who carried out this session and the quality of the kit they use - they have no vested interest in what my engine will do - and their approach to problems as they arise was methodical.

I drove the car before set up on their trade plates - I haven't driven anything like this before, to say I'm pleased is an understatement :thumb:

Correction.....
Its not a Piper 285, its the equivalent of a Kent 218.