Stig's GTR-S

[hans_x3]

I'm looking for "Stig's GTR-S" video. The link www.ultima-gtr.info/movs/stigs-gtr-s.wmv doesn't work anymore.


Summary: Supercharged Ultima at Snetterton
Format: wmv (5MB)
Submitted By: Anonymous
Submitted: Thursday 27th November 2003
Credits: Chris James 2003
Video: www.ultima-gtr.info/movs/stigs-gtr-s.wmv

Viewed: 2867 times
Description: In-car footage from Snetterton behind the wheel of a 6.3 litre Supercharged Ultima GTR

[gtr-gaz]

It was on d3vine's web site at www.speedmachine.net ,but I have just looked and that's not working either

Perhaps d3vine could explain?

[stig]

That's because it's hosted elsewhere

You can view it here:

www.pistonheads.tv/video.asp?id=51&nr=1

[hans_x3]

Very cool video, not to mention your GTR...

You still have it?

How many BHP?

Did you run standard factory suspension?

How heavy is the supercharger?

[stig]

Hans:

You still have it?
- nope, sold it and am now in the process of building a Can-Am

How many BHP?
Dyno'd at 630

Did you run standard factory suspension?
Yes and I'm not sure why you'd want to do otherwise?

How heavy is the supercharger?
Just the charger unit, or the engine? Either way, haven't the foggiest (ie. I have no idea)

The car was literally, a missile.

[d3vine]

www.speedmachine.net is back up. Currently, there are more than 70 Ultima car related videos in the video archive.

Sorry for any inconvenience, the domain name was expired. I had to renew it today.

[Vesuvius996]

Stig. You always were a loon.

Respect.

[hans_x3]

Why Can-Am? Performance wise, is it any better than GTR?

WRT to suspension, I just asked becaused it looks fast on the track

Did you have dry sump? If not, any problems with wet sump @ track?

WRT to supercharger, I ask because it "looks heavy". I was always thinking why not to have it on the side of the engine (not mounted on top of the engine) in order to lower C of G.

stig said:

Hans: You still have it? - nope, sold it and am now in the process of building a Can-Am How many BHP? Dyno'd at 630 Did you run standard factory suspension? Yes and I'm not sure why you'd want to do otherwise? How heavy is the supercharger? Just the charger unit, or the engine? Either way, haven't the foggiest (ie. I have no idea) The car was literally, a missile.

[stig]

hans_x3 said:

Why Can-Am? Performance wise, is it any better than GTR? WRT to suspension, I just asked becaused it looks fast on the track Did you have dry sump? If not, any problems with wet sump @ track? WRT to supercharger, I ask because it "looks heavy". I was always thinking why not to have it on the side of the engine (not mounted on top of the engine) in order to lower C of G.

Hi Hans,

Decided to build a Can-Am as there was nothing else that could touch the Ultima in terms of performance, handling and loooks for your money - and I mean, nothing. I looked at Ferrari, Porsche, you name it. It wasn't a performance choice, but I'd already built the GTR and wanted a matching set of web-sites

The other thing is that put me off those 'marques', was that:

a) The interiors felt as though they came from a 1970's Rover

b) The build quality was not as good as I could achieve with an Ultima! I'm sure this will ruffle a few Porsche owners' feathers, but it's true. The thing is YOU get to decide how well your Ultima is built, simply because it's you building it and not some factory production line.

Re. suspension, as you can hopefully see in the video, the car is plently fast enough/handles well enough to destroy pretty much everything you come across - road or track. Whilst in that video the overtaking of the Caterhams on the back straight was fun, it was the fact that I could catch and overtake in the corners that was much more impressive! I do have several years of racing experience behind me, but the Ultima is a very flattering car to drive. That said, it can bite you back and HARD if you don't respect it Then again, any high performance car will do the same. This is why there have been a couple of comments about understeer. Understeer is dialled into the suspension by most manufacturers because it's safer than oversteer for most drivers. Let's face it, there are plenty of people out there who have never even driven a RWD car. You can dial it out as Gareth (G Man) said in another post. The factory suspension, with bespoke coilover dampers, is excellent and more than good enough for 99.99% of drivers.

Finally, I didn't run with a dry sump as I had the accusump accumulator. Whilst a dry sump is definitely the best bet if you're going to do lots of track work, especially with long, high-g corners, the accusump does the job almost as well and is a lot cheaper.

Supercharger was quite heavy, but the car is so light and powerful that it makes little difference. The vortec style chargers that side mount are an alternative, but I can't comment on how good they are? Seem a lot smaller so dunno whether you'd get the same volume of air/boost pressure as the Weiand Roots 177 that I had?

[Jeff-Texas]

If you mean 'centripetal' superchargers which resemble the impeller of a turbo, Stig, then yeah, they can get up to 2300HP and for big block V8's: [url]www.procharger.com/models.shtml[/url]. :-) Vortech themselves make some competitive ones so far as I know (i.e. it's not just procharger with such high-HP units), and who knows, maybe more than 2300 HP.

But just like how a bigger turbo housing which takes more room in the engine bay will often make more than a small turbo (depending on trim, etc.), I think that F-4 is a bit larger than any 'small' centripetal blowers on most cars. ;-)

Now what I want to see is an engine which actually *needs* the equivalent of twin-turbo except for it to be supercharged -- with TWO of those F-4 blowers, pah-hahahaha. You can already bet that there's a Honda somewhere, putting out a whole 300 HP but which has TWO F-4's on it leading into the 2" throttle body (ported, of corse, up to a whole 2" ;-) )

...to match the 2" dual-exhaust pipes with 10" diameter tips, the goldplated wheel-spinners, tires so oversized they rub (mounted on 4" offset wheel-spacers, of course, so the top edge also catches lots of drag by hanging outside the wheelwell and is such a dangerous offset that it's ready to shear off the lugnuts if they actually cornered as fast as the car's look suggests), and aftermarket 'aero' kit with lots of sharp angles to the bodywork. ;-) Oh, and lowering springs -- by cutting the existing springs, of course. :-)

N.B.: I am sorry to owners of the aforementioned types of Hondas everywhere; I really am very, very sorry for you. :-)

Barghh, pistonheads has 'service unavailable'.

>> Edited by Jeff-Texas on Sunday 24th April 14:21

[eliot]

Jeff-Texas said:

If you mean 'centripetal' superchargers which resemble the impeller of a turbo,

Eh?
Did you mean "centrifugal"

[Jeff-Texas]

eliot said:

Jeff-Texas said: If you mean 'centripetal' superchargers which resemble the impeller of a turbo, Eh? Did you mean "centrifugal"

It depends on your perspective: If you're the impeller blade, you're exerting a centrifugal force on the air; if you're the air, you're exerting a centripetal force on the impeller blade which is equal to and opposite of the centrifugal force -- oops, I'm thinking in terms of statics; in the dynamic impeller, there will be both forces, but the forces may not be equal. Centrifugal probably is the more commonly used term by laymen for all forces of rotational acceleration (often simply for not knowing the word 'centripetal' is a word), but both terms can be used so long as you get the vector in the correct direction. It's only a matter of po-tay-to vs. po-tah-to, but here's a longer explanation:

I try to look at things from the centripetal perspective (i.e. with the vector pointing toward the center of the radius) because that's just how I was taught it's easier to look at things in engineering classes... The important thing is consistency: By always assigning the positive value to one direction, we avoid confusion about whether, this particular time, we assigned the inward or outward force (centripetal/centrifugal, respectively) as the positive or negative force, and thus avoid simple (yet costly) mistakes because you might be looking at your last number, the end-result, and if that number is negative, you don't want to need to ask yourself, "An hour ago, when I started calculating each force to determine the net force, did I presume the inward or outward force to be the negative one, and am I therefore looking at a net inward or outward force?" :-) This -- not emphasizing consistency, except in this case, consistency in their UNITS (metric vs. imperial) -- is how NASA infamously lost a satellite or another piece of equipment, or sumphin er other.

>> Edited by Jeff-Texas on Sunday 24th April 19:33

[chuntington101]

Centripetal is the actual force not centrifugal! centrifugal is a term made up to discribe the abarent force pulling you outward when you spin things quickly. the "outward" force is actualy you being forced to change direction constanly. i new A-level physics would come in usefull one day

and dont diss the hondas too much! TTS curently have one (on stock internals) thats making about 350bhp and the guys have plans for over 500bhp with a bigger rotex blower and lower comp internals!

do you guys think a ProCharger will fit in an ultima? it could be the ultimate bolt on power adder as ATI claim big things form it. also be nice to fit a big F1-R on a 383 AS blower engine and run it upto about 20psi. the only down side to these SC is that boost builds the faster you spin it not a constant amount like you get with a Roots style blower. but if you could fit a "waest gate" to limit the presure to say 20psi then you should get full boost by about 5000rpm holding all the way to the red line hehe. a lot more than you could get from a Roots!

here is a link to the pics section on the Procharger site. www.procharger.com/chevy.shtml

thanks Chris.

[RickH]

I was always told that centrifugal force didn't actually exist (as such) and was just a term used to make things easier to understand.

Centripetal force is the one that we're supposed to use.

Rick

p.s. or am I wrong?

[atom290]

You are totally correct! A centrifugal force doesn’t exist, and as correctly stated it is design by physicists to explain the phenomenon of an object moving away from the centre of the circle.

The true force comes from the fact the acceleration is to the centre of the circle, and this is the centripetal force. F=ma.

Core 8 years since I did my maths/astrophysics degree.

[edfoxuk]

the link is dead again

[jeff-texas]

chuntington101 said:

do you guys think a ProCharger will fit in an ultima?

Sure, especially since you're removing the PS pump and you can reverse the impeller to mount the Procharger behind the pulleys, you could probably even mount it low on eiher side, under the 'V' of the V8, to keep the Cg low.

Sorry for this late reply, BTW...

chuntington101 said:

the only down side to these SC is that boost builds the faster you spin it not a constant amount like you get with a Roots style blower. [but if you fit a waste gate...]

Yep, but you can use a BOV (not a wastegate) to even-out the power-curve. Or for better efficiency, a recirculating BOV (puts the blown-off air just upstream of the impeller), since otherwise, you'd be compressing plenty of air for nothing as soon as the BOV opens and that takes more and more HP, probably about 50 wasted HP on a SBC @ the 20 psi you mentioned! OTOH, this non-linear building of HP means it's a less twitchy throttle @ low RPM, and Chevy says this issue is what made them go to an electronic throttle for the LS2/7. Add to that their easier ability to be used with a lighter, simpler air-to-air IC, and I tend to prefer them over roots or twin-screws, but twin-turbos are probably even better than both -- except for the arduous plumbing in most cars. They all have good and bad points.

chuntington101 said:

a lot more than you could get from a Roots!

I think a roots can make quite a lot when it's the right size and pulley-ratio: e.g. They use them on top-fuel to make mega-HP. :-) ...although that is with nitromethane, classified as an explosive (not a flammable) by the US government. :-) Still, you're talking big HP even with gasoline. ;-)

chuntington101 said:

and dont diss the hondas too much!

I wasn't dissing Honda's, just people who trick out cars in really poserish (not to mention appalling and nonsensical) ways, and Hondas are the most-often desecrated in this way. ;-)

e.g. The people I was talking about and have seen, they put 3" dual-exhaust pipes on their cars despite that being completely unnecessary for the 250 HP or so their engine makes; it's a complete poser mod typical of the ricer community. The 350 HP you mentioned is nicer than what they were putting out, but Chevy has put that out from emissions-legal, **bone-stock** engines for years. 500 is even better, but Chevy will put that out in bone-stock form this autumn, which is probably before the company you referred to even gets that from a highly *modified* Honda. :-) Even then, these engines are usually in a FWD car which can't put that HP to the ground too well...

chuntington101 said:

centrifugal is a term made up to discribe the abarent [apparent?] force pulling you outward when you spin things quickly.

Pretty much. It's not really 'made-up,' but isn't truly an 'outward' force as the dictionary def. calls it, unless by 'outward' they meant tangential not radial. I was actually thinking of adding a paragraph to describe how the 'outward' (centrifugal) force is drawn as a tangent to the circular path in a vector-diagram, rather than drawn 'outward' as in 180* opposite the centripetal force vector, 'outward' from the center of the circle -- complete with the examples of planets and a skidpad -- but was a bit lazy and didn't want to completely dismiss Eliot's point.

(e.g., in an abbreviated way than what I was gonna post 2 weeks ago: The planets have gravity pulling them toward the sun which is balanced by the centrifugal force of their motion pulling them 'outward,' 'away' from the sun, and the skidpad has the tires' grip resisting the car's centrifugal force, but if the sun disappeared suddenly (into another dimension? ;-P ) or the car hit ice, the centrifugal force would actually propel the planets on a TANGENT from their (roughly) circular orbits and the car would be nearly that path since ice has a *little* grip. TANGENT, rather than moving along any RADIAL line, directly 'away' from the sun (with a straight line which touches the center of the circle and goes toward any point on the circle is defined as 'radial,' and a staight line which never touches the circle's center but touches one, miniscule point on the circle and is perpendicular to the 'radial' line is defined as 'tangential').

>> Edited by jeff-texas on Saturday 14th May 07:48

>> Edited by jeff-texas on Saturday 14th May 07:58

[chuntington101]

HAHA. jeff you are 100% complete on all acounts. the honda engine i was talking about was designed for use in the Civic Typ R though and i dont recon a LS2/7 would quiet fit in the front of one;-) but your point is still true!

on the "waest gate" idea, i dont think there would be that much energy lost from venting boost once a set presure is reached! I tried to put down what i was thinking but gave up (my minds better than my english and its a monday ) so could you please exsplain why you think it would cost so much power?

thanks Chris.