44 replies to this topic

[Turbo Phil]

Out of interest Graham how is 39deg optimal ?

[ivanhoew]

Personally I can't see that charge cooler working efficiently. Optimum ACT's (Air Charge Temperature) is 39 degrees. Don’t be fooled that the low the ACT’s the better performance is obtained...

graham ,just to be sure ,are you saying you can prove that any air temp below 39 degrees c is bad for power ?

Temps below 39 degrees will be 'ok', but to get the best power you need to stay as close to 39 degrees as possible.

have you any proof or supporting evidence of this graham , id be really interested to see it .
(whoops sorry phil didnt see that youd asked allready ,were not getting on your case graham ,just interested in new data ..)

Edited by ivanhoew, 31 May 2010 - 08:48 AM.

[Grahamxx]

Ok, for those who don't know I run a company called GRSmotorsport, I design and develop intercoolers/radiators for performance cars around the world. I've worked with Adrain Newey daughter and Richard Nobles son at Sussex University helping them design & develop cooling systems for their race car project.

Family history is:
GRSmotorsport has a wealth of experience in heat transfer.
My great grandfather invented the Clayton-Still wire bound tube radiator; this was patented and licensed for manufacture for use on the London buses in the 1920’s.
My grandfather wrote a book called “Some Factors Affecting the Design of Heat Transfer Apparatus”. He also worked for Rolls Royce in the development team designing the radiators and oil coolers for the Spitfire during the 2nd World War.
My father who brought me up around vintage & post war cars worked for Normal Air Garrett, designing cabin control pressure systems for aircraft. He also helped design the Re-breathing diving system for the James Bond film ‘For Your Eyes Only’.
I was offered a job with the Williams Grand Prix team in 1996 in their fabrication shop, but unfortunately due to my daughter being born prematurely I was unable to take the position.

10 years ago I set up my company.

Last year I worked on 2 other projects with 2 impendent tuning companies who required 39 degrees as their optimum ACT’s. Some scientist boffen has worked out that 39 degrees is the best temp to have.
Construct of cores ie glued or vacuum brazed is important to know and how the air enters the core through the end tanks and the way it moves through the core are very important, get these parameters right and you get the ideal cooling/temps required.

(Mods, please feel free to remove any parts of this contents you are now happy with)

[ivanhoew]

Some scientist boffen has worked out that 39 degrees is the best temp to have.

good post graham ,thanks for the cv ,very impressive . do you happen to know if the boffin is published anywhere ?

[Grahamxx]

Some scientist boffen has worked out that 39 degrees is the best temp to have.

good post graham ,thanks for the cv ,very impressive . do you happen to know if the boffin is published anywhere ?

Leave it with me, I'll do some digging and report back! I have a friend of mine did is doctorate at Bath university on making his lectures (friend of our family!) Type 51 Bugatti supercharger more efficient. He also said 39 degrees was the best temp to have, I’ll have a word with him this week…

[ivanhoew]

Some scientist boffen has worked out that 39 degrees is the best temp to have.

good post graham ,thanks for the cv ,very impressive . do you happen to know if the boffin is published anywhere ?

Leave it with me, I'll do some digging and report back! I have a friend of mine did is doctorate at Bath university on making his lectures (friend of our family!) Type 51 Bugatti supercharger more efficient. He also said 39 degrees was the best temp to have, I’ll have a word with him this week…

excellent thank you ,incidentally ,do you know geriant owen ?

[Grahamxx]

Some scientist boffen has worked out that 39 degrees is the best temp to have.

good post graham ,thanks for the cv ,very impressive . do you happen to know if the boffin is published anywhere ?

Leave it with me, I'll do some digging and report back! I have a friend of mine did is doctorate at Bath university on making his lectures (friend of our family!) Type 51 Bugatti supercharger more efficient. He also said 39 degrees was the best temp to have, I’ll have a word with him this week…

excellent thank you ,incidentally ,do you know geriant owen ?

Yes my father does. Gerinats father owns Babs the car that was trying for the land speed record in Wales in the 30's...

[ivanhoew]

ask geriant about robert that tuned his gipsy moth engined car on the chassis dyno in ipsden, years ago .

[AndrewJ530]

I'd hazard a guess that 39oC is the temperature where you get the highest air density without the fuel condensing back into liquid from a vapour? Could be wrong but it seems logical.

[joe90]

I have kept an eye on charge cooler temps (only on the outside casting) & the temp has never gone over 55c.
Having a water cooler as vmax (plumbed of the engine im asumming). water temp at 88c dose not add up to me?
I might be getting it all wrong?
JOE

Is your charge cooler using its own water supply, or using the water from the engines radiator?

I havnt got a charge cooler as i dont think its needed. I just didnt make myself clear. im asuming that it runs of the engine rad but not sure. No one seems to say what temp charger is to start with that was all.
I am running exhaust wrap on exhaust manifold & inlet manifold to try & keep things as cool as possible

[Grahamxx]

I have kept an eye on charge cooler temps (only on the outside casting) & the temp has never gone over 55c.
Having a water cooler as vmax (plumbed of the engine im asumming). water temp at 88c dose not add up to me?
I might be getting it all wrong?
JOE

Is your charge cooler using its own water supply, or using the water from the engines radiator?

I havnt got a charge cooler as i dont think its needed. I just didnt make myself clear. im asuming that it runs of the engine rad but not sure. No one seems to say what temp charger is to start with that was all.
I am running exhaust wrap on exhaust manifold & inlet manifold to try & keep things as cool as possible

A charge cooler should have its own water system, totally independent from the engine. The system will have its own pre-rad, water pump, water reservoir, hose’s etc. Using the water from the engine won’t help at all. Having said that the large turbo Escort Cosworth used a charge cooler as standard with an intercooler using the water from the engine!! But this was to do with emissions so I was told!.

Having a water jacket on the top of the charger as shown in the picture above is on the wrong side, there’s no heat there, its underneath where you need the cooling, problem is there isn’t any room!! As long as you are running under 10psi of boost a charge cooler or intercooler isn’t required as stated by David Vizard

Edited by Grahamxx, 31 May 2010 - 09:26 PM.

[supermotolee]

can you please find some evidence towards this 39 degrees intake temps? as i have always thought the lower the better or atleast low and consistant?
thanks lee

[Grahamxx]

Ok had an email from my friend who did his dissertation on making a supercharger more efficient, he’s going to give me his project on a memory stick for me to read through, but said a lot of his studies were done using tech books based on forced induction there is states the best ACT’s to use is 39 degrees C, however his theory is ‘using the optimum temperature to maximize air density and saturation of fuel droplets. This would give you the biggest bang for a given swept volume’. Soon as I have more info I’ll pass it on….

[ivanhoew]

Ok had an email from my friend who did his dissertation on making a supercharger more efficient, he’s going to give me his project on a memory stick for me to read through, but said a lot of his studies were done using tech books based on forced induction there is states the best ACT’s to use is 39 degrees C, however his theory is ‘using the optimum temperature to maximize air density and saturation of fuel droplets. This would give you the biggest bang for a given swept volume’. Soon as I have more info I’ll pass it on….

great ,thanks for taking the time graham ,,this would seem to suggest that the optimium temp would vary depending on the fuel delivery methods ..eg a finer droplet size from a su ,would have a differet optimum temp to a larger size from a weber ...also , if fuel is injected after the charger ,then possibly a much lower air temp would create greater v e ,without fuel drop out occuring .

another concept to consider ,is , operating range of the engine ,and port speed through the induction system ,higher the rpm band used ,the less the dropout problem would create a need for high inlet temps ,and the higher the port speed ...ditto .

personally i am of the opinion that the coldest that is realistically obtainable ,the better ,but id be very happy to learn that im wrong if it proves to be so !

regards
robert

[Verbaliser]

Sort of understand the quoted Delta T values of the M45 charger itself, but is there a similar 'change in temperature' for a given rpm/psi to describe the drop in ambient temperature caused by the suck through action in the intake pipe?