scootz
|
| posted on 25/7/08 at 06:52 PM |
|
|
Calculating Rad Size
Is there a formula for establishing how big a radiator needs to be for any given engine?
More specifically, I have a 4.2 V8 and I want to use 2 radiators (1 in each side-pod). Basically I want the smallest units possible.
|
|
|
|
|
mr henderson
|
| posted on 25/7/08 at 07:30 PM |
|
|
My approach would be to find out the size of the radiator from the engine donor car, then find some smaller units that would be the equivalent when
added together.
Modern radiators are amzing. The radiator I took out of the Audi 1.8t (180bhp)recently was about half the weight of the MGB (90bhp) radiator from the
NG that I am assembling for a customer
John
PS presumably the Ultima radiators don't suit, (or are too expensive)?
|
|
|
thunderace
|
 posted on 25/7/08 at 07:30 PM |
|
|
are you building an ultima spider
i went round ingilston track in an ultima a few years ago and its still my dream car.
got it on film
|
|
|
thunderace
|
| posted on 25/7/08 at 07:34 PM |
|
|
need i say more
http://www.ultimasports.co.uk/records/part8.html
can anyone tell me why topgear wont touch it.
[Edited on 25/7/08 by thunderace]
|
|
|
scootz
|
| posted on 25/7/08 at 07:35 PM |
|
|
Cheers guys.
I had a second hand Ultima one in the kit I bought. Only problem is it is huge and heavy!
Designed for a small block chevy, so overkill for a modern aluminium V8.
Sold it for pretty decent money, so have some dosh available to pursue something more suitable.
|
|
|
mr henderson
|
| posted on 25/7/08 at 07:41 PM |
|
|
quote:
Originally posted by scootz
Designed for a small block chevy, so overkill for a modern aluminium V8.
Well what really counts is how much power the engine is going to produce, waste heat being an inescapable by product of IC engines.
Granted your engine is going to be more efficient than an SBC, but only by a fractional amount. So, how much power is it going to produce, and are you
still thinking about forced induction?
John
|
|
|
scootz
|
| posted on 25/7/08 at 07:52 PM |
|
|
Nope - no supercharger.
Keeping it NA and hoping for 400+ BHP.
|
|
|
mr henderson
|
| posted on 25/7/08 at 08:36 PM |
|
|
quote:
Originally posted by scootz
Nope - no supercharger.
Keeping it NA and hoping for 400+ BHP.
Well then I reckon you can expect SBC levels of heat production. Still, a couple of small efficient aluminium radiators should keep the temperature
under control as long as decent fans are fitted.
How about that guy (deneo)who was advertising on here recently, the chap who welds aluminium, he reckons he can make radiators
John
[Edited on 25/7/08 by mr henderson]
|
|
|
D Beddows
|
| posted on 26/7/08 at 02:55 AM |
|
|
Nope, a good few years ago I did an entire 15,000 plus word dissertation for my degree on a very similar topic and there are too many variables,
mostly aerodynamically related, which basically mean you pretty much have to 'suck it and see' unless you can stick it in a wind tunnel
for a few days to test it under various conditions - however I would say either you need to slow the air down in front of the core with some kind of
ducting in which case you can have a small radiator with a dense core or if you can't slow the air into the rad down then the core needs to be a
bit more open but the radiator needs to be a bit bigger...... but then it depends on how you vent the hot air from behind the radiator as to how well
it works etc etc etc and tbh I can't usually be bothered explaining it all any more  maybe one of our 3LA (3 letter acronym to us mere
mortals) 'mid engine' specialists will come along to tell you what the latest fashion is with the F1 designers they've been
interviewing this week 
But in answer to your original question... no
[Edited on 26/7/08 by D Beddows]
|
|
|
scootz
|
| posted on 26/7/08 at 09:45 AM |
|
|
Why thank you Sir.
I had thought it may be an 'experimental' procedure!
|
|
|
jamie1107
|
| posted on 26/7/08 at 01:32 PM |
|
|
id be very interested in seeing some photos of the ultima bits and some idea of the quality of the kit
im considering building one after the current locost is built using the ali chevy ls series engine with bit of forced induction
i did hear that z cars did a twin bike engined version but i never could get any info on it
aparently the chassis is good for 1000hp plus and was used as the test bed for the meclaren f1 motor but im not sure how true it is
there prices jst seem a little steep for some of the bits eg tilton rack quaife would make you a custom rack for half that price and avo would supply
remote resivoir 4 way adjustable shocks for less then they specify for their units makes me think ist a bit ott
still i think for the perforance its still worth the money possibly altho there is a new retoga coming out
|
|
|
scootz
|
| posted on 26/7/08 at 08:39 PM |
|
|
The quality of the kit is A1, but you're right... if you source parts from elsewhere, then you'll save a fortune!
I thought it was just fantasy when I heard that some guys had spent over £100k on their builds, but having got myself involved in the Ultima scene,
then I saw for myself that some certainly have (although the average spend seems to be just over £50k).
Me? Well, I bought an unfinished Spyder kit (left the factory in 1999), and I hope to bring it in at a much lower cost! It pretty much had every
factory part required to finish and I got it at a great price.
Basically, mine will be no frills. As light as possible, and if it doesn't NEED it then it ain't getting it! No creature comforts as
it's being built to use when "I'm in the mood" - not as a cruiser.
I've not compromised on the essential bits - my kit came with what was then the standard factory brakes (Granada) and a set of more recent
Protech shocks. I've sold both of those as I don't fancy either. I bided my time and have since picked up a full set of GTR AP brakes,
and the most recent Intrax shocks (the brakes had covered less than 950 miles before that particular car was written off and the shocks had never been
out of their wrappers due to the owner upgrading straight to Ohlins!). Saved £2.5k on these 2 items alone (against new factory prices!). Make that
£3k by the time you factor in the funds raised from the sale of the outgoing items.
I'm not using the Ultima twin tank set-up, as there's plenty of room in the engine bay for a central tank (using an Audi V8 instead of a
Chevy and this leaves a gap to fill). Picked up a new whistles and bells tank from the States for peanuts, and will sell the unused factory set up
(the factory charge over £1k for the twin tank kit, so assuming I sell my unused kit at less than half new price, then I should still be well into
profit in that department!).
A word of warning though... if I was buying a new kit (GTR or Can-Am), then I would defo be buying all bits from the factory. It's a hell of an
investment at 'new' prices and you want as much factory support as you can get! I've bought some bits and bobs from them that
I've not been able to source elsewhere and found them great to deal with.
On the LS engines... Cobra's and other period replica's... absolutely! A track biased car... not so sure! Just not enough rpm and the
torque is just dumped on you!
The McLaren association is true - there's a good 'history' write up on the Ultima website.
|
|
|
jamie1107
|
| posted on 27/7/08 at 12:30 PM |
|
|
ap and ohlins very nice kit indeed
i have seen some part built kits going for silly money so that may be an option half of the reason i wanted to avoid getting all the bits from ultima
is i intend to make most of them
your porbably thinking im crazy now but i do cnc milling and tig welding hence i hate paying for things i could make
i would love to see some pictures of your build should you happen to be taking any its true what they say a picture is worth a thousand words
although you have already helped me out in telling me the brakes were originally ford based which means i can make my own billet hubs i have been
saving some 4 1/2 inch titanium bar which came from a job for just that now all i have to do is work out the rack and uprights lol
|
|
|
scootz
|
| posted on 27/7/08 at 12:38 PM |
|
|
No, don't think you're mad at all... if you have the tools and the skills, then more power to you!
|
|
|
