"Ray's AKA demonfire's XR4Ti build up"

exST165 · Post by **exST165** » Wed Apr 14, 2010 12:12 am

Thanks! The latest issue of GrassRootsMotorsports had an article on aerodynamics that raised some issues with the XR4Ti that I'm wondering about. The article states that the "stagnation point" - the point where air is divided between going above or below the car has been getting lower and lower in recent automotive designs.

It also states that for a splitter to work the splitter has to extend out past the bumper. Looking at the way the front fascia slopes down pushing air that is below the bumper below the car, I'm wondering if there could be performance gains by basically making a airdam that extends vertically down from the bumper (with openings for the radiator) so air is pushed around the car instead of under it.

My understanding is that the XR4Ti was the result of some serious wind tunnel testing so they must have had a good reason for designing it the way they did.

Has anyone experimented with anything along these lines?

Thomas

Post by **hEaT** » Thu Apr 15, 2010 8:30 am

Ray · Post by **Ray** » Thu Apr 15, 2010 7:30 pm

^^
Slow.

Thanks for the pic joe.

Ray · Post by **Ray** » Sat Apr 17, 2010 6:17 pm

Please excuse the cell phone pics. I very rarely remember to grab my camera. Oh, the fitting to the block is NOT 3/8 NPT, it's 1/4 NPT. I luckily had a spare plug. Also, i put a 3/8 NPT drain (nothing like having a russell fitting for your coolant drain) into that pipe i built.

Dinner (i have to go grill this in a few)

She turns 3 next frickin' week. Man how time flies. She loves the merkur. She even goes "vroom! vroom!"

And the obligatory hilarity of my euro plate. What sound does my car make?

Camaro5690 · Post by **Camaro5690** » Sat Apr 17, 2010 6:32 pm

love the plate!

Ray · Post by **Ray** » Mon Apr 19, 2010 6:34 am

First points event was yesterday.

My car is in need of some megasquirt.

Ray · Post by **Ray** » Mon Apr 19, 2010 6:37 am

Matt's Blood Monkey - we need to figure out why this car is so damned boost laggy.

edit:

Member's only pictures are up too. This is from the 11th.

Ray · Post by **Ray** » Mon May 17, 2010 6:49 am

Some more cone dodging fun. Friend of mine's car was in the shop for some transmission work, so he drove my car yesterday. Lucky for me, i was able to beat him in my car, which is saying a lot as he's pretty damned good. I ended up placing first in class, and third overall out of all classes, which is a personal best.

Of note, i took the side pipe off, as the band clamp stretched a bit and was coming loose.

and here is Liam being Liam...

Ray · Post by **Ray** » Mon May 17, 2010 4:32 pm

At autocross, i'm one of the "tech" guys. Here is me at work.

Checking wheel bearing play on a BMW.

Inspecting a potential FTD contender...

And yes, even if you drive a porsche, i have to check your helmet.

Some MORE pics of liam destroying my tires...

out the box

just imagine my face watching him run - even the announcer said something like "Ray, what are you thinking letting Liam drive your car?!"

I just shook my head.

okay, remember, slow is smooth, smooth is fast...

let's do another run after i remind him, there is NO ABS. NO traction control. Yes, the car responds well to smooth inputs... (he picked up .9 seconds)

damnit liam easy on the brakes!

and ALMOST on 2 wheels. Great picture.

DSPXR4ti · Post by **DSPXR4ti** » Mon May 17, 2010 7:51 pm

Hey Ray,

Your pic's look great, I love getting pic's of my XR to just to see how it looks at speed but I do have some question for you. How was the surface? How old are your tires? your using a T5? what is your F&R springs rates? and how much does your XR weight? are you tire blueing on the out side edge? and with all that how did the XR feel to you.

Ben

Ray · Post by **Ray** » Mon May 17, 2010 8:25 pm

surface was mostly smooth - a few inconsistancies but nothing too bad. tires are fairly old - 4 seasons, but still pretty grippy. stored inside past winter in furnace room. Yes, am using a T5. spring rates are 500 front, 325 rear (coilover, equates to 867.5 rear in stock location), weight is about 2680. tires have no signs of blueing. car is rock solid in steady state cornering with an oversteer bias, unless you throw her in too hard, then understeer. has some understeer in quick transitions on turn in / then some oversteer depending on throtte input.

looking at the pics, and seeing someone else drive - i'm thinking my front spring rates could be a bit higher. maybe 550 instead of 500.

DSPXR4ti · Post by **DSPXR4ti** » Mon May 17, 2010 9:08 pm

Ray,

You have coil over right? Well..Try lower the front of the XR before you put higher spring rates, this will give some rake, which will add camber just double check your toe before you run again.

What are your shocks & struts adjusted to? you have the koni yellows right?.

Are you running the 245 40 17's?. all around.

Ben

Ray · Post by **Ray** » Tue May 18, 2010 6:24 am

I can try to lower the fronts - i have a bit more room before they rub.

The fronts are koni yellow - adjusted to about 1/2 to full firm. Rears are non-adjustable QA-1 Carerra 4/4 racing shocks. (rears are also adjustable height)

i'm running 275/40/17's all around.

Also, i have camber / caster plates up front - so i can easily get another 3* of camber if needed. right now i'm running -2.5* static.

Ray · Post by **Ray** » Mon Jul 12, 2010 6:54 am

Breaking in the new tires.

edit: new pictures

This is one way to come into the stop box

Ray · Post by **Ray** » Thu Jul 29, 2010 1:19 pm

No new pictures really (have a couple but nothing exciting) but the megasquirt is in and installed. Thanks to Dave for building it for me.

Wired in some "mods" for fan control. Launch control hooked to the clutch; made a bracket with a normally open switch. Now, to tune.

Put in 83lb/hr injectors (@ 42psi), removed the VAM, and... well, it's a MS.

Didn't realize how complicated everything was but overall i'd recommend it... once i get it tuned. Or rather, once hEaT tunes it for me