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Home > Technical Chat > What normal & max boosts are y'all using ?

fab

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Parisien Turbo Expert

Paris\' suburb

20th May, 2007 at 08:12:53pm

leave turbo for real racers ????????
who are you?


robert

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uranus

20th May, 2007 at 09:29:12pm


On 16th of May, 2007 at 01:14pm ppj_racing said:


On 16th of May, 2007 at 12:50pm Turbo Shed said:
higher Ron may help reduce det but so does a low compression ratio or a good intercooler or if its well set up etc etc etc.

high Ron fuel in a standard metro turbo engine will allow a bit more boost (depending on how high the Ron is) but a decent engine with all the bells and wistles can run higher boost on standard pump fuel

and yes 10 to 20 Psi is gauge pressure, if i'm right then if that was actual pressure then 10psi would be -5psi gauge so is a vacum



Yup, off-boost your gauge should show a negative figure
Most n-a engines have a volumetric efficiency well below
100 ..so when your boost gauge shows O psi, you have
100 VE and can get-on with some serious boosting



this is nonsense,a reading of zero in the inlet manifold does not mean 100 % ve ,it means the manifold is not being restricted by whatever is supplying it with air ,and bears no relation whatsoever to the cylinder fill efficiency which is generally restricted by the inlet valve.




Provided the other hardware can stand-it, espesh temp
as you say, if you use a RON of 120 ,, or some
Avgas (even 100LL) or better, xylene or even better
methanol (runs cooler + much more power), you
can run a base CR of say 7.8 i.e. 15.6 at 1 bar boost
and get better results.



unfortunately this is also nonsense ,saying a 7.8 to 1 cr equates to 15.6 at 1bar does not take into account so many factors , valve closure point, dynamic inertia, anti reversion, temp of head, mixture, spark timing, external air density ,all affect the cr in the cyl at a set rpm .





That said, a lower Base CR does give you less lag
and less power


um.......no


How much are you getting at the wheels?




please build your engine ,following your theories, and show us the results , i feel it will be very educational and highly entertaining for the observers .

regards robert.*smiley*

Edited by robert on 21st May, 2007.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

RogerM

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I like nice quiet girly Minis

Cheltenham, Gloucestershire

21st May, 2007 at 07:36:02pm

I was going to type what steve did ...

There are road cars and race cars .... road cars don't work as well on the track as race cars but race cars don't work at all on the road .......

Anyway, as a fuel systems designer, I have to say I would always run the highest (dynamic) CR I could for any given intended performance level. Low CR high boost motors are always going to be more of a handful than higher CR lower boost .... motors that are a handful are harder to drive and unless your surname is Senna or Schumacher I'd suggest building an easy to drive engine.

There is an even better way .... high CR and high boost ..... needs precise control but it IS possible so long as you keep everything in your favour as far as component selection is concerned .... start with an alloy head!!

Every day is a school day ...........

How fast and how expensive ...... the same question...

On 27th of Sep, 2007 at 12:45pm Jimster said:
why do you you think I got a girlfriend with small hands?

stevieturbo

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Northern Ireland

21st May, 2007 at 08:01:59pm

Does an alloy head really make that much difference ??

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

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