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Davemk1 last won the day on September 29

Davemk1 had the most liked content!

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About Davemk1

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    Average Joe Driver

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  • Car Details
    Westfield Mega S2000
  • My Location
    Bozeman, MT USA

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  1. Flat-ish underbody -

    It might work that way. I think since the wheel wells are still fully open on the sides that they would be a bigger, lower pressure area and that any air that wants to come out would do so out that way. I spaced the trailing end of the diffuser down 5/8" to have the lower edge of the strakes look level and the lower the roof angle of the diffuser. The steepest part of the roof measures about 20° which is a bit steep to maintain attached airflow and my spacer lowers that by a bit. Again real string tests and a Go Pro to show what's going on back under they will be the real test. I suspect, just going by the numbers, that the angle will still be too steep (especially on the outer two side sections) and that it would benefit from being lower still. This is pretty easy to test with cardboard and duct tape and if it proves to be beneficial I can make a lower roof angle. Years ago I competed in a Lotus Elise and it was super tail happy during dropped throttle at speed - scary stuff. I did a lot of testing of airlfow and was able to make a new diffuser that, along with a front splitter and rear wing really tamed it. It was very stable and quick after that work. Fun stuff. dave
  2. Flat-ish underbody -

    Flared sides could be worth considering....I'll need to do some careful studying of the airflow with the flat bottom in place and see where air is going at this point and what the engine temps are like. It would seem that the trailing edge of the flared sides would create a nice low pressure area to draw out air from the engine bay. We'll see. dave
  3. Flat-ish underbody -

    Thanks. I think you'll find that once you drive the car that the engine bay remains shockingly clean. Even when I drive on very dry and dusty roads the engine engine compartment stays very clean. This suggests to me that the area is under positive pressure and that the air feeding it is clean. I'm thinking that the air enters the engine area through the radiator and through the openings in the side where the front suspension protrudes from the bodywork and the air exits out the bottom. This idea of the air exiting the bottom is one of the main drivers of fitting the flat underbody....if the air is going out the bottom that means that it's a low pressure area and it's pulling air from the engine area. I'd like the underside to be as low a pressure as possible and don't think feeding it from the engine area is helpful. So I put the flat floor on more to keep the air from going down than from going up. I'll do some Go-Pro string movement tests come spring to see what the air is doing now. We'll see. And yes - there needs to be areas for water and gravel to get out. The corners are cut big enough to let any small stones kicked up by the race slicks fall out and all three panels have about a 2 mm gaps all around for water to run out. I look forward to really testing it. dave
  4. Flat-ish underbody -

    I know the shape of our cars is rather brick-like and that the effort to make it more aero might be silly. Looking at the body work there's not that much to be done....but the underbody is ripe for improvement. I recently set out to make the car more slippery and with any luck reduce lift at speed by cleaning up the air flow on the underside of the car. One of the major aims here was to work hard to limit the weight I added. My emotional weight-budget was 5.5 lbs. - nothing bad would happen if I exceeded that but without a goal it could get out of hand in a hurry. Starting at the front is a custom splitter to help reduce the amount of air that goes under the car in the first place. My SCCA competition rules say that the splitter can't be any wider than the bodywork itself so I'm rather limited here. The splitter is made of a carbon/balsa/carbon sandwich and is silly light. The plate and all the hardware to hold it in place weighs 1.0 lbs. Moving rearward I decided to fill in the space around the engine and sump and make it as flat as I reasonably could. I used 1/16" thick carbon sheet and it's three separate pieces. I'd like to have made it from one sheet but that would be a damn big sheet and very spendy. The three smaller pieces can be cut out of a 2' x 2' sheet. The three pieces and all the hardware weigh in at 8 ounces. Lastly I fitted a rear diffuser made by Mark at Carbon NV. The fit is very good and it was simple to come up with a way to have the whole thing attach with only three fasteners and it's completely solid and rattle free. The diffuser and hardware weigh in at 4.7 lbs. This brings the flat underbody project to a total of 6.2 pounds......more than I hoped for but I can live with it. I have no idea how it will perform on the autocross course but I can say that the car feels great going down the road and interestingly it is noticeably quieter....particularly behind me. It makes sense when I think of it as the diffuser largely closed up the inverted U shape the rear bodywork has. Now much of the air moves out the back instead of swirling up and into the area around the fuel tank and differential. Pretty cool - not expected but welcome. Winter has just started here and it will be a number of months before I can test it on-course but the skiing should be really good soon! dave
  5. Change from TPS to MAP for the Alps etc

    Interesting. I've had my car on a dyno a few times and the AFR is very good. It makes me wonder if it would be rich if I went to a lower elevation. dave
  6. Change from TPS to MAP for the Alps etc

    I live at just shy of 5000 feet and often drive to over 7200 feet. Am I correct in thinking that typically the ECU senses altitude/air pressure? dave
  7. Just bought my first kit car

    I like it! dave
  8. OCD cleaning

    Rubbing alcohol is the ticket for cleaning coolant off most anything. dave
  9. Autocar Road test

    I wonder just how well set up the cars that the factory lends out to test are? Many years ago I worked for a very high end bicycle company that sent its bikes out to national bike magazines and as often as not the reviews would have a number of small negatives that in the end would add up giving a negative impression of an otherwise wonderful bike. So we took the step of having our best mechanics tweak and test and re-tweak the bikes until they were just right before any journalist ever got near it. And when the bike came back from the test it was gone over and test ridden and cleaned to perfection before it went back out the door to be once again tested. And....every bike always came home to check over before it went to the next test. Journalist are not kind to gear and most don't care if they pass on bikes that are compromised in some way to the next magazine. This process resulted in glowing reviews and a real life bump in sales - so worth the time to get the bikes just right. I wonder if Westfield, and other car companies, take the steps necessary to present their products in the best possible light. I recall a number of years ago EVO magazine tested the then new Miata and they had little good to say about it and the tone of the piece was largely one of disappointment. Their core complaint was the handling and the details of their complaint all pointed to a poor alignment. As I read it I wanted to jump into the pages of the magazine and set the toe properly just so they would talk about something else. I can't fault the magazine - are they supposed to report that they think the car would be great if only it had a proper alignment and tire pressures? No - they test the car they are given. It feels like Westfield might do well to have their best guy assemble the demo cars and make sure they ride and handle just so and that they are 100% rattle and squeak free. It's time consuming and therefore not cheap but it's time/money very well spent. If I can make my own car handle and ride just right and be free of rattles and squeaks surely the factory can do it and do it faster and cheaper...and no doubt the reviews would be more positive and be less "it's not as good as a Caterham but it's cheaper". Properly done they could have "it's every bit as good as a Caterham and much cheaper" and no doubt sales would increase. dave
  10. Mega s2000 Omex throttle bodies

    The map installed during this dyno run was just as Omex sent. I have since had the ECU unlocked and will put the car back on the dyno and do some tweaking this coming spring and see what gains might be had. I suspect they will be very small however. The fueling was spot on so the only real way to get more out of it is with timing and since it does not employ a knock sensor it's a bit risky to go far down that road. dave
  11. Mega s2000 Omex throttle bodies

    Not to try to sway you one way or the other but I find that the induction noise on mine isn't so much louder but just different. I happen to like the sound but i wouldn't spend the money to get it. The power gains and rapid throttle response is the reason I made the change and they did not disappoint. In my case I gained 19 hp and 8 ft/lbs at the wheels and these gains give a much different feel. Combine this with the super quick throttle response and it really suits the car well. My before and after dyno charts are attached. I think the choice to install the ITB's or not might fall to how you use the car. If the car is a tourer and you like to cruise in it than the power and throttle response might not be a real life added benefit. If you drive it hard and find yourself using the last of of throttle pedal travel often then the ITB's could be a very good choice. dave
  12. Mega s2000 Omex throttle bodies

    Mine are working just as they should - I think you'll be pleased. dave

    Do you know what ratio your differential is? I'm just suggesting that it's possible that you might benefit from having a taller ratio. The engine spins the trans and the trans then spins the differential and then the wheels spin. If you changed your 1st gear ratio it would be better and the rest of the gears of course would remain the same....and this could be a good thing. If you change the rear diff ratio you will change all the gears in the trans effectively making them all taller. This too could be a good thing. It depends on what you want out of the car. It's certainly much easier to pull the rear diff and have the ring and pinion swapped out than it is to pull the engine so that you can pull the trans and then have the trans rebuilt. It might be worth finding an online gear calculator that allows for all the variables to be input so you could see how the different options would change the way the car feels and drives. dave

    Have you considered a taller rear end ratio to make all the gears in the box more usable? dave
  15. Battery

    I've been using one of these for a long time now to start my S2000 and it's been flawless. It starts the car without issue even if the Westie has been parked outside overnight and it's well below freezing. It's so light it feels like an empty box when you pick it up. Cool technology. dave https://www.braillebattery.com/index.php/braille/product_batteries/g20