Hahahahahahaha
Actually a series 1 looks quite good with Vitesse wheels:
"Carl Gibbs" gurgled happily, sounding much like they were saying:
I am NOT going to click that link. You bastard.
I used to build dyno systems as you may know. I doubt that they would measure a 3bhp change on two different runs due to such things as air/temp/other changes and thats on a dyno with very controlled parameters. The chance of the road test/stopwatch electronic version on a ipod is a little bit optimistic! If you did it a hundred times each, logged the air temp and atmos pressure at the intake and made sure the wind was exactly the same and the enguine was exactly the same temp, then averaged the result might show something!
You will get a bigger change by doing few cheap mods. Like skim say 1.5mm off the heads, sort the valve seats, etc. That wlll give you about 5 or 10 percent more go.
No, we didn't.
It must have slipped my mind, even though you appear to find a reason to include that in almost every post you make.
It was a P6 motor 10.5 compression and 178bhp before skimmed 1.5mm heads etc. No idea where that leaves the compression but with no thermostat fitted it stays cool and no detonation probs.
Cheap tuning made about 200 at wheels without nitrous. (with tubular "stag" rover conversion 4 into 1 headers) Drove like a smooth factory car. The green pipe just takes cold air from the inner wing. The air box (no filter) snout is cut off. The air box helps midrange power.The car rocks. Rover engines are so low output that almost any tuning work pays huge dividends.
Listen...
What kind of cost was involved? Been thinking about doing the Capri so the costs would be similar.
Very little. You need to buy some tubular headers, for best results which cost. But not essential. I started with the P6 restrictive cast manifolds cos I had them and they are small.which helps in the Sierra.. The dyno showed a fairly big improvement with these replaced with tubular ones only on nitrous. Without gas was just a few bhp more. So not essensial.
Skim heads? Your engineering shop will quote you, but expect anything from
20 quid each if you speak to the right guy upwards to whatever they think they can get out of you... Valve seats you can do at home with cheap tools.Dyno time and a file or new needles / springs sorts the carbs after you bin the filter and keep the air box with the narrowed part of the snout cut off. It needs it too as the air filter and the air box intake is quite restrictive. Inside the manifold just after the carbs is a strange tube type bit that restricts breathing that is designed to "launch" any stray fuel droplets into the air flow. Great for emmissions crap for power. Not all have this. It costs 15bhp...
The P6 motor is 10.5 to one to start with so it makes more power than the SD1. Thats the only reason it does. The valves are actually slightly smaller on a P6 rover I think.
Going the other way, the olde range rover motor is really slow to pick up and rev and makes just over a hundred horsepower. It has really low compression and thats the only difference as far as I could tell. Cams/valves same. it sounds crap. I have no idea why they would do that. Its so low you could turbo a stock one.
As for nitrous they can easily cope with 300 extra if built well or just healthy.. But you can build your own 140bhp extra system for peanuts.
Not in practice - the way output was measure changed in the years between the introduction of the RV-8 and the SD1. The SD1 had a much better exhaust system and bigger valves.
And remember only RV-8s made up to about '71 had the high compression. So plenty of P6 engines didn't.
Yep and less compression. Dunno about the way the power was measured other than both were hp. Both were manufacturers enfine figures and neither are usually "honest"
But I can tell you that my P6 motor was an odd factory blueprinted one supplied to champion and as a test unit to develop plugs for. It had never been in a car and was run on an engine dyno for 40 hours in 71/72. Then it was given to a school as a static display. It sat there for many years untill I offered 40 quid for it... It was still all shiny so I couldnt resist..
On a bosch braked chassis dyno sat in a sierra (not that that should matter) with stock everything including cast manifolds and a home made 4 inch straight through exhaust it made 149 at the wheels. Stock SD1 rovers make around 120 to 130 rear wheels on this same dyno.
So I am not sure you are correct. It made more in the mid and bottom end too.
Really? Didnt know that.. Mine had 10.5 stamped on the motor an the engine number was a non existent according to parts departments 000999... And the haynes also said 10.5 and 178 hp...
On the same dyno with increased compression, valve seats tidied up, filters binned, air box modified, and lumenition, and filed needles (d shape) to richen things up in the midrange and at full power as it was weak due to the filters/air box mod which obviously worked, and tubular headers meant for the stag conversion it did a genuine 195 sae rwhp. 265/279 with some nitrous.
I do know that the valves are a big restriction on these engines and so increasing compression makes a big difference as it improves the pumping efficiency and cylinder emptying and filling out of all proportion due to the lower dead space volume. And it allows the timing to be later improving power due to less pressure before top dead. and higher average pressure after top dead.
Just thought I'd drop in here that my big plans for nitrous on the Mondeo went by the board when I was persuaded we needed a new car and managed to convince her to be happy with Vamps 328i.
I can't seem to get any oomph in me now to nitrous the Mondeo when it will end up with less than the stock BMW :-/
That's not to say I won't end up tinkering with the BMW, but I doubt if nitrous will be the first choice... there's about 50bhp to be had just with a new manifold, throttle body and rechip.
Basically, the earlier way was with the engine on a test bed using that exhaust system and cooling system, whereas later ones were as installed. And as you said the P6 had a very restrictive exhaust - the SD1 very much better.
I couldn't have either. ;-)
You'd have needed a blueprinted SD1 engine for a true comparison. Lots of rough edges on these engines.
They changed the compression when 5 star was withdrawn. Too much lead...
I had a '69 Series 1 3500 with the high compression engine which was great. Apart from being an auto. On one occasion on the M40 got it to hydraulic tappet pump up in top gear - it simply refused to go any faster. Downhill. Just before where it used to finish before the turn off to Oxford. About 125 mph. Anymore and it would have been airborne.
Indeed. Dunno what the limits are for a pushrod engine - but plenty manage
70 bhp/ltr so lots of scope.
Why RV8 when a yank V8 with a load more power is cheaper to build?
Its the same weight as the pinto. Its cheap as yank but alloy?
Asmall block would work but they tried that in the Sierra (south african XR8) and they handle terrible... Wheelspin everywhere as its nose heavy and rear drive. I drove one when the owner spotted my V8 Sierra at the pod. Beat him pretty easily too since I had Nitrous.
You'll buy an RV8 in reasonable condition for a couple of hundred pounds and get anything you need for it easily. Don't think that's the case for any Yank V8 - unless you want to importing from the US.
Correct on both accounts.
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