LIL has full boost and full revs
- Thread starter Diver944
- Start date
After some thought I believe you could be right on a normally aspirated engine. MAF, MAP or the barn door AFM all measure the air going into (or actually in) the inlet manifold. So, if you can force more air in, it should read and compensate for the additional air pressure.
However, a turbo can produce more manifold pressure than the engine can handle and has to be limited by the waste gate. Granted, if the air is denser in the first place it doesn't need compressing as much ,so won't get as hot, so will produce more power - Turbos are noticeably quicker on cold damp days than they are on hot dry days.
You are now into the realms of how much extra power is available. An F1 car is getting a charge of air running toward it at 200mph. On a track day you might get 120 mph air occasionally. If you then consider that an S2 will consume approaching 75 litres of air a second at 6000 rpm, that air has to be travelling damn fast down a 2" diameter inlet tube.
In F1 fractions of a second make a difference. In real life I don't think cutting a big scoop in the bonnet (assuming you even get it in the right place) is going to be worth the hassle.
Some interesting details here:
http://www.sportrider.com/tech/146_9910_ram/
How far of thread are we allowed to go [
]
Pete
http://www.sportrider.com/tech/146_9910_ram/
How far of thread are we allowed to go [
]Pete
It just goes to show how non cut and dried it is - very interesting though.
How far of thread are we allowed to go [
Pete
You stick with me Pete and we'll take it where we like [
]The origin of this thread is so old now, with such acute diversions, I don't think it makes much difference. If we get pulled up though we will argue that the discussions are all power related. [
] 
ORIGINAL: John Sims
There is a Dyno Dynamics Rolling Road at Sussex Performance Centre on the outskirts of Horsham (apparently!)
Heat soak can be an issue but also is achieving the optimum cylinder temperature to ensure efficient (and thus powerful) combustion. According to Chris at Weltmeister Turbos are particularly sensitive to this.
The last time he ran Beaky I asked him what he did to increase the power on each run. Apparently he did nothing; each increase was due to the rise in cylinder temperature. He generally does three of four runs before the hp stabilises.
Tyre heating isn't an issue as the tyres shouldn't be spinning. Beaky spent an entire day on a dyno a couple of years back - not an experience I would necessarily like to repeat.
Herewith a picture of his exhaust manifold glowing red hot:-
Wonder what your egt's were there John? Looks scary hot!
DivineE
New member
I wouldn't panic from what I can guess they go that colour every time you go for a spirited drive. You just don't see it! Generally if you get home at night and open the bonet you'll see all the exhausts still glowing even on tickover 5mins after you've been driving it hard. I have a picture of it somewhere and it was the same on both my turbo's.
I think it was principally due to heat soak from so many runs. We actually ended up with a fire as the radiant heat of the exhaust melted to plastic pipe junction on the clutch master cylinder. Clutch fluid got on the exhaust and caught fire. I was really happy about that []
While the manifold will get very hot it does have nice cold air passing by normally, which you don't get on a dyno, so I think this was a bit of an extreme case. Ben is right, you can get the manifold hot enough to see glow at night if you try hard enough. This was day light though.
]While the manifold will get very hot it does have nice cold air passing by normally, which you don't get on a dyno, so I think this was a bit of an extreme case. Ben is right, you can get the manifold hot enough to see glow at night if you try hard enough. This was day light though.
Diver944
Active member
Well I've had a pretty frustrating day []
Knowing that I have a trackday at Donington on Sunday next week and knowing that they have an even lower driveby noise limit than Bedford (87db as opposed to 87.5db which I just pipped), I set out to try and lower the volume from my car. It's all induction, turbo and dump valve noise which comes straight out of the cone filter since the MAF kit was fitted. I spent most of the morning measuring, cutting and then fitting Dynamat noise damping sheets to the inside of the engine bay behind the N/S popup lamp which is where the air filter is now situated.
Then I took the car for a test drive and to be honest the noise inside the car seems unchanged [] so I deposited my son at the side of the road and did a few high speed, full throttle drive bys while he captured them on camcorder. Back at home the playback reveals to me what you guys have been raving about. My car sounds like a jet fighter on afterburner [] I have to admit it sounds lovely from the outside, but I can now understand why I was black flagged for noise at Bedford.
I only hope the volume has been reduced slightly so I can get under the 87db driveby at Donington. The video is uploading to YouTube now and I'll post the link in a minute
]Knowing that I have a trackday at Donington on Sunday next week and knowing that they have an even lower driveby noise limit than Bedford (87db as opposed to 87.5db which I just pipped), I set out to try and lower the volume from my car. It's all induction, turbo and dump valve noise which comes straight out of the cone filter since the MAF kit was fitted. I spent most of the morning measuring, cutting and then fitting Dynamat noise damping sheets to the inside of the engine bay behind the N/S popup lamp which is where the air filter is now situated.
Then I took the car for a test drive and to be honest the noise inside the car seems unchanged [
] so I deposited my son at the side of the road and did a few high speed, full throttle drive bys while he captured them on camcorder. Back at home the playback reveals to me what you guys have been raving about. My car sounds like a jet fighter on afterburner [] I have to admit it sounds lovely from the outside, but I can now understand why I was black flagged for noise at Bedford.I only hope the volume has been reduced slightly so I can get under the 87db driveby at Donington. The video is uploading to YouTube now and I'll post the link in a minute
Diver944
Active member
Oooh that uploaded quickly []
http://www.youtube.com/watch?v=vBJSzkWtn-c
It's repeated 3 times as it is over so quickly
]http://www.youtube.com/watch?v=vBJSzkWtn-c
It's repeated 3 times as it is over so quickly
I too love the noise and it makes me question the db limits that only govern the level rather than the noise itself. Meaning there are some noises like a chainsaw, or a leaf blower early on Sunday morning that are plain annoying however something as impressive as Lil's note, on a racetrack to boot, is considered over the limit. Doesn't seem right to me?[] What sort of muffling system are you running Paul?
] What sort of muffling system are you running Paul?
edh
New member
ORIGINAL: Diver944
Well I've had a pretty frustrating day [
Knowing that I have a trackday at Donington on Sunday next week and knowing that they have an even lower driveby noise limit than Bedford (87db as opposed to 87.5db which I just pipped),
Paul - the website says the limit is 98db.
http://www.donington-park.co.uk/circuit/faq.asp#Q6
If you do get close, it's just a matter of keeping to the right of the pit straight for the first 100 feet or so & maybe not giving it full throttle straight out of Goddards
Diver944
Active member
Doh [8|] I was sure I read somewhere it was an 87db driveby, but I can't find that now
Never mind because I lost my place for this Sunday as I was wanting to ensure my car was quiet enough first and now it is full. I will probably do next Saturday 24th March instead with Donnys own Crashzone organisation []
Never mind because I lost my place for this Sunday as I was wanting to ensure my car was quiet enough first and now it is full. I will probably do next Saturday 24th March instead with Donnys own Crashzone organisation [
]
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