Post your dyno curve here
Discussion
davelittlewood said:
Mines started pinking since I put in iridium 6s.
I’ll drop some super unleaded in it as I run it 95 usually.
If it’s still pinking I’ll have to go back to get the ignition timing changed.
Your fueling AFR must be near the knuckle (lean) for a plug change to cause pinking/knock I’ll drop some super unleaded in it as I run it 95 usually.
If it’s still pinking I’ll have to go back to get the ignition timing changed.
the OE TVR plug resists this well being a cooler & recessed electrode style 
hence your plug change stirring things up & TVR probably covering their arse's in det terms back then , dont live with it however RV8 pistons are not known for being bomb proof Edited by Zener on Friday 9th July 10:28
davelittlewood said:
For shaft power a 20% transmission loss is not a bad guess but you can't do that with torque.
The torque at the crank could actually be lower than that at the wheels depending on the gear ratios.
https://x-engineer.org/automotive-engineering/chas...
So when you use this formula what torque figure do you come up with. The torque at the crank could actually be lower than that at the wheels depending on the gear ratios.
https://x-engineer.org/automotive-engineering/chas...
Are Dyno operators not just doing a blanket calculation using 20% on both graphs?
338 Bhp on standard heads using 38 mm inlet and Catted on a 450 is mightily impressive.
Zener said:
Your fueling AFR must be near the knuckle (lean) for a plug change to cause pinking/knock the OE TVR plug resists this well being a cooler & recessed electrode style hence your plug change stirring things up & TVR probably covering their arse's in det terms back then , dont live with it however RV8 pistons are not known for being bomb proof
It sounds like a paint can being rattled furiously from quite low revs, increases with revs the OE TVR plug resists this well being a cooler & recessed electrode style hence your plug change stirring things up & TVR probably covering their arse's in det terms back then , dont live with it however RV8 pistons are not known for being bomb proof Edited by Zener on Friday 9th July 10:28
Sounds like they pushed the advance to the Max as the engine power figures suggest.
Running it on 95 and a hotter plug is always a risk when it’s mapped for 99.
Thrashing it on 95 is a no no so I was told by the MBE mapper.
.
I use 95 for when the engine barely goes over 4000 revs as in cruising. I also bite the bullet and use 99 if I ever put my foot down.
You have ran this engine on 95 throughout which must include putting your foot down!
This combination has resulted in this situation, that’s if it is the timing.
I told Jay my car would be ran on 95 as I rarely even accelerate hard on open roads so my timing is possibly safer than yours which is partly why MINE HAS LESS POWER Dom Trickett!
Many years ago I adjusted the timing on my short lived 5.0 for max power on the dyne. Power was about 334 from memory.
Did a drag day at Shakey on a hot day and surprise, surprise. Two pistons broke!
The 5.0 pistons are very week with a very thin ring gland at the top of the pistons.
And here it is 9 years ago with the orange wheels, (pre stripe).
https://youtu.be/QPIMq1Vd9x4
Did a drag day at Shakey on a hot day and surprise, surprise. Two pistons broke!
The 5.0 pistons are very week with a very thin ring gland at the top of the pistons.
And here it is 9 years ago with the orange wheels, (pre stripe).
https://youtu.be/QPIMq1Vd9x4
Yep the problem with adjusting a dizzy for max power is that the timing for max power is more than required in the midrange, so in the midrange it will detonate. Adjust for min best timing in the midrange to be safer.
If the engine dets its bits off with just a change of plugs there's something very odd going on. The spark timing hasn't changed (the narrow tip of an iridium plug might possibly allow the spark to jump the gap fractionally earlier? I don't know for sure just a guess) .. but if the plug tip is getting hot enough to allow pre-ignition (ie fuel combustion before the spark has actually fired) then altering the timing won't change that. Whatever the reason for your rattle can sounds it is a serious issue and needs investigating and correcting ASAP!!! No engine should have that effect from just going to a slightly different plug, even one point hotter rating.
If the engine dets its bits off with just a change of plugs there's something very odd going on. The spark timing hasn't changed (the narrow tip of an iridium plug might possibly allow the spark to jump the gap fractionally earlier? I don't know for sure just a guess) .. but if the plug tip is getting hot enough to allow pre-ignition (ie fuel combustion before the spark has actually fired) then altering the timing won't change that. Whatever the reason for your rattle can sounds it is a serious issue and needs investigating and correcting ASAP!!! No engine should have that effect from just going to a slightly different plug, even one point hotter rating.
ivanhoew said:
well done magpies , that must be more than a stock v8 S ?
Yes more power but less torque, also an extra 1000+ revs. So they will be well matched but totally different drives - similar 0-60 times of around 5 seconds.By the end of this year (or so) there should be 8 Jag engined S's, it is becoming a popular upgrade.
Edited by magpies on Thursday 15th July 09:52
magpies said:
ivanhoew said:
well done magpies , that must be more than a stock v8 S ?
Yes more power but less torque, also an extra 1000+ revs. So they will be well matched but totally different drives - similar 0-60 times of around 5 seconds.By the end of this year (or so) there should be 8 Jag engined S's, it is becoming a popular upgrade.
Edited by magpies on Thursday 15th July 09:52
hats off 
phazed said:
Obviously not a standard 4.6.
What has been done to the engine?
A great graph. Did you have an emerald system fitted by Joolz?
Should have said in the original post.What has been done to the engine?
A great graph. Did you have an emerald system fitted by Joolz?
V8D rebuilt 4.6 - assuming stage 3 heads - Stealth Cam - Emerald install by Joolz, and various other bits and bobs.
Here’s mine, first graph is without Joolz’ blended base second one is with it. Joolz said the standard chimaera 500 intake was potentially restricting the top end. V8Developments ported intake on the way. Joolz said that with this I should see the top end gains that the blended base normally deliver.
Car is V8 Developments 5 litre cross bolted with 72mm plenum, blended trumpets and act smooth bore running Emmerald.
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