When is a front splitter necessary?

[pb3]

With an Ultima GTR in mind is there any speed/conditions that would necessitate the fitting of a front splitter to reduce front-end lift?

I must admit that I have not experienced any to date even when topping out at 172mph but I have a 200+ target in mind. I have a rear wing (set flat for top speed) and guess if anything this would encourage front-end lift with the rear being pressed down. Are their any examples out there doing 200+ without any additional aerodynamic aids?

[GreenV8S]

Be careful, a front splitter is a dead easy way to produce tons of downforce at the front but usually increases rear end lift. This combination tends to make the vehicle unstable at high speed. If you're talking about high speed straight line stuff I'd have thought you want to be ensure the rear downforce is generous compared to the front.

[G Man]

PB3

I have always run a splitter and of course it has been stable at 200 mph

Why take the risk of being without it ?

[GTWayne]

Is it not the general consensus that removal of the rear wing is most beneficial for top speed runs?
Surely, it would then be a logical step to leave the rear wing on if you are also running a splitter, if nothing else so that they will counteract one another (given that you posses the data on both items and therefore know of their respective effects in relation to each other?).

[d3vine]

So how much downforce does the splitter and rear wing generate? Also, how much drag does the splitter and rear wing generate as well? Or is it possible to create downforce without drag with the rear wing and splitter?

[G Man]

GTWayne said:

Is it not the general consensus that removal of the rear wing is most beneficial for top speed runs?
Surely, it would then be a logical step to leave the rear wing on if you are also running a splitter, if nothing else so that they will counteract one another (given that you posses the data on both items and therefore know of their respective effects in relation to each other?).

Wayne not sure if you wanted me to answer, I only run with a front splitter and either a full wing on minimum or remove the top plane, at Brunts the removal of the top plane might at a marginal 2mph per run

G

[GTWayne]

G Man said:

....2mph per run....

Yo G,
It was a general remark but in reply to that very useful information that you have been kind enough to impart: '2mph' is '2mph' right?

[gtrclive]

GreenV8S said:

Be careful, a front splitter is a dead easy way to produce tons of downforce at the front but usually increases rear end lift. This combination tends to make the vehicle unstable at high speed. If you're talking about high speed straight line stuff I'd have thought you want to be ensure the rear downforce is generous compared to the front.

Think I'd prefer steering ie. front down force at any speed.... just make sure you've dialed out your bump steer because at that speed small changes in toe make big differences.....

PS same could be said about the rear wing, big down force at high speed makes the front light if you don't fit a Splitter.... so removal of the rear wing when you don't have a splitter might not be a bad Idea on Terminal Velocity runs ... Basical fitt both or none IMHO....

[GreenV8S]

gtrclive said:

Think I'd prefer steering ie. front down force at any speed

The problem is that with more grip at the front than the rear, the car can go unstable at very high speed. This is the sort of thing that is probably only going to happen to you once. If you're going to do that sort of speed I think you need to be fairly scientific about measuring the lift/downforce versus speed, then project it to make sure the lift is within acceptable limits at your target speed and the car is lighter at the front than the back.

[G Man]

GTWayne said:

G Man said:

....2mph per run....

Yo G,
It was a general remark but in reply to that very useful information that you have been kind enough to impart: '2mph' is '2mph' right?

2mph if you have sooo much HP .... like me Wayne

[carmad426]

Does anyone know how much downforce the Ultima can produce i thought i read somewhere the rear wing could produce 800lbs of downforce but i could be wrong. So if anyone knows how much roughly it puts down that would be great.

[GTWayne]

G Man said:

GTWayne said:

G Man said:

....2mph per run....

Yo G,
It was a general remark but in reply to that very useful information that you have been kind enough to impart: '2mph' is '2mph' right?

2mph if you have sooo much HP .... like me Wayne

You know it!

[bluesatin]

For my lowly speeds upto 170-180 with and without front splitter I would say go with the splitter. The car has been wind tunnel tested with it and you can go a lot faster in limited distance as it makes braking a lot better especially if you adjust the brake front rear bias.

Edited by bluesatin on Saturday 20th January 06:06

[andygtt]

Seeing as there is no data available from when the car was photo'd in the wind tunnel its down to people like Gman to tell us what its actually like at 200mph.

The theory is that the problem with taking the wing off would not neccesarilly be high speed stability when accelerating at 200mph, but when the car is braking from that speed.

[gtr-gaz]

Well, mine felt very stable at about 180mph (no splitter) including a bit of heavy braking.
I would have had no hesitation going faster if that had been possible

Surely, the sloping front gives enough down force as it is?


edit: make sure your door catches and hinges are faultless!!

Edited by gtr-gaz on Saturday 20th January 17:12

[andygtt]

its the air going under the front clip that would cause the lift.... the front splitter encourages air to go over or around the car rather than under it.

[bluesatin]

Trust me the car is a more stable with the splitter than without. Also agree on the door latches!

[pb3]

I think that having aerodynamic/down force assistance can generally only be a good thing, otherwise why would all those GT cars etc use them. I was a little curious as to when a splitter would be essential and if at some speed the front of the car could lift to the point in which it becomes airborne. How many have done 200+ without a splitter and not experienced any lift? As stated the fact that the car is low with a small frontal area may negate the need and the car will be safe. Although other positive effects seem to come from the fitting such as better braking performance and a more stable front end when cornering at speed etc.

Also from what I have read in other posts about splitters the actual forces on the splitter itself are not too great and the downforce is generated by the fact that the air flow have been better directed over/to the side of the car. The splitter is not acting as a wing creating down force by itself, having said that it needs to be firmly fixed as would anything else facing those conditions at speed, anybody disagree (before I gaffer tape a bit of plywood to the bottom of my front clip)?

[andygtt]

As blue says the front splitter does do a lot.... he was there when it was literally ripped from my car at 170+mph due to the downforces on it.
If you fit one it must be fitted very securely, bonding as well as securelly fixing seems to work.

[GreenV8S]

The forces on a splitter can be quite high (hundreds of pounds). Don't confuse weight on the front wheels with stability though. If you're getting a significant amount of lift at the rear and downforce at the front, it'll feel fine right up to the point it lets go.