keltik Posted April 12, 2022 Share Posted April 12, 2022 Replace gear oil with ATF. Run some 0w20 in the engine. Replace tyre air with nitrogen. Purge all farts from body cavity before racing. Edit: Wonder if Mr @kpr has tested different engine oil and gear oil weights for effect? 1 Quote Link to comment Share on other sites More sharing options...
kpr Posted April 12, 2022 Share Posted April 12, 2022 doing a massive burnout to get the oil temps up helps! 8 1 Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted April 12, 2022 Author Popular Post Share Posted April 12, 2022 End of month. Exhaust. Gonna happen! 14 5 1 Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted April 12, 2022 Share Posted April 12, 2022 Someone somewhere said you can get cheap titanium bolts (second hand) from aircraft refits. (Helicopters maybe?) Replace all the bolts on the car with titanium ones. Also lay a huge cable before you race. (Logs weigh more than farts) Quote Link to comment Share on other sites More sharing options...
Roman Posted April 12, 2022 Author Share Posted April 12, 2022 Nah that's way too much effort. Like I could replace 200 bolts, or do one thing like remove the ABS pump for same amount of weight haha. Ultimately though I still want to go do some trackdays in this, and keep it road going. Not super specialize as a drag car. But there will probably be another 40 pages worth of barrying going on. 7 1 Quote Link to comment Share on other sites More sharing options...
sheepers Posted April 13, 2022 Share Posted April 13, 2022 only 40? 2 Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted April 13, 2022 Author Popular Post Share Posted April 13, 2022 With a margin of error of +- 500 pages Speaking of barrying, The full results from nightspeed came out. So although I got eliminated in the first round by some poor tactical judgement (lining up against the fast wagon straight away) I was third fastest in class so that's cool. There were 163 cars in total, and my car is the median haha. There were 81 cars faster than mine, and 81 slower. Looking at Trap speeds vs quarter mile times and you can see what's needed to achieve a particular quarter mile time. My trap speed is very low for the time that I'm doing, compared to other cars doing the same time. Which suggests I'm getting off the line quite well and I'm likely pretty close to max potential. The only car faster than mine that did a sub 100mph Trap speed was an A45 AMG Mercedes, which ran a 12.927. Must have had an epic launch! Or maybe hit the brakes early. But no 60ft data included so not sure. However you can see that there are cars hovering just under/over the 100mph mark which are doing way slower quarter mile times. So they'd have heaps more potential with better suspension/tyres rather than more power. The slowest car with a 100+ mph trap speed was a Mirage that ran 103mph over the line, but ran a 15.3 Must have had a really horrible launch! It's got the trap speed to easily do a low 13 or a high 12 instead. EDIT: I just noticed the other sub 100mph dot. This is funny, you're not allowed to run quicker than 11.0 at Nightspeed without getting in trouble. This was a GTR skyline that ran a 10.961, with a trap speed of 97mph hahaha. So obviously absolutely hauling arse off the line, then probably hitting the picks half way down the track to avoid doing faster than an 11. 15 4 Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted April 18, 2022 Author Popular Post Share Posted April 18, 2022 Rear suspension. I removed the Ohlins rear shocks, which both seemed stuffed. So I thought I may as well pull one apart and see what's going on. I found that the spring steel shims on the pistons, which need to flex out of the way to let oil through to control rate of dampening. These were just snapped off. Hence not doing anything! Some of the seals were a bit so-so, but the broken shim stack was definitely the main issue. It's supposed to have a circular shim that covers that big oil port thing. So I've been doing some investigation and it looks like the seals and shims are all orderable, if I measure them up. However... A friend of mine (Thanks Adam!) bought a fairly modified Vitz RS for some gravel autocross stuff, and the low suspension it came with wasnt helpful. So I swapped him some factory suspension and the Vitz RS front bumper I previously hoarded, in exchange for the rear of the HKS setup. These have an adjustable platform and what looks like a stiffer spring. Total weight difference is about 1kg extra per side. Not too bad seeing how I can now set the rear height to suit better for drags (whatever that means for a FWD...) I gave it all a cleanup and made sure the threads were clear then fitted it all up. Looks a bit better with the rear lower now, and no rake. In other news, I figure it might be handy to setup flat shifting for the drags. In order to do this you need a clutch switch. This means I can have throttle blip on downshift with e-throttle as well. Cool! I had a clutch switch fitted to the endstop of the pedal in my Carina, but it was pretty useless. As you need to have the switch exactly on the clutch biting point, not the at end of travel which is where I had it mounted. Since it was fairly useless I never played around with the related features all that much. So this time around, different plan. I've got an accelerator pedal sensor from a 350Z. These have a little lever thing on them, so its fairly easy to retrofit to something else. It looks like the easiest spot to try fit it, will be pushing against the clutch fork rather than the pedal in the cabin. So this will obviously output a variable voltage based on clutch position, rather than being an on/off switch. This idea has some pros and cons compared to a simple switch. The main problem is that my ECU can recognize a clutch - only as a switch. So I need to get a bit creative to get it to turn it into an on/off signal. Basically I need to wire an ECU output directly to an ECU input which is a bit silly. So it's a bit of a bodge to work around an older ECU. Luckily I've got lots of IO to spare so it's not a problem. The main benefit of this setup is that I can adjust the switch point in software, rather than having to mechanically adjust the physical position of a switch. It also means that I can potentially set multiple conditions for turning the switch on or off. I can make it so a really light touch of the clutch will disengage cruise control, but then you need to reach the bite point for flat shifting or downshift throttle blip. It'll take a bit of experimenting to get it working right. But it should be fun. Throttle blip downshift will be pretty cool, and a bit of assistance for my absolutely flogged out synchros in this box haha. It looks like the weather might be a bit sketchy by this weekend, but if it's looking fine I'll head to Nightspeed again this coming Friday. Hopefully with flat shift working nicely by then, and see if having functional rear suspension helps the launches at all. 15 4 Quote Link to comment Share on other sites More sharing options...
anglia4 Posted April 19, 2022 Share Posted April 19, 2022 How will it know that you are down-shifting? Like will you set it up to only blip if you clutch in while also braking? Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted April 19, 2022 Share Posted April 19, 2022 Clutch in while the pedal is off? Only a madman would keep the foot flat while downshifting. Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted April 20, 2022 Author Popular Post Share Posted April 20, 2022 8 hours ago, anglia4 said: How will it know that you are down-shifting? Like will you set it up to only blip if you clutch in while also braking? Yes correct, the trigger for downsift needs foot on brake and clutch at the same time. (And throttle less than 20%, but I'm imagining its hard to have 20% throttle with no foot on it) So yeah I got this all setup this morning for flat shift (havent configured the blip yet) So the clutch engagement point is at about 30% of travel (from the floor) But doing some testing I need the engagement point for the fuel/ignition cut to be more like 70% to stop the motor from either bogging or revving too soon. However its absolutely savage when it's setup right! Previously the 2nd>3rd shift was about 450ms to get back to full throttle from first lift. Now it's more like 210ms. With flat shift: 1st to 2nd takes around 310ms, 2nd to 3rd is around 210ms, 3rd to 4th is around 190ms All fairly consistently around those times. RIP shift forks hahaha. 13 5 2 Quote Link to comment Share on other sites More sharing options...
Yowzer Posted April 20, 2022 Share Posted April 20, 2022 Now to replace the synchros with dogs / chuck a sequential in it Quote Link to comment Share on other sites More sharing options...
ajg193 Posted April 20, 2022 Share Posted April 20, 2022 I'm just picturing a miss-shift from 2nd down into 1st and hitting 17000 rpm 2 Quote Link to comment Share on other sites More sharing options...
Roman Posted April 20, 2022 Author Share Posted April 20, 2022 I dont see how it's any more likely to happen than before though? I'm still using the clutch, just not letting off the gas. I dont think I've ever accidentally shifted into 1st going for 3rd. I think the absolutely chooched synchros wouldnt allow that anyway haha. Ahh well, good thing that motors are cheap 4 Quote Link to comment Share on other sites More sharing options...
ajg193 Posted April 20, 2022 Share Posted April 20, 2022 I wasn't suggesting it's more likely with the new setup, I'm just picturing it happening. For some reason it is too easy to hit reverse instead of fourth in my brother's capri (some modern falcon gearbox), hell of a grinding noise 1 Quote Link to comment Share on other sites More sharing options...
Yowzer Posted April 20, 2022 Share Posted April 20, 2022 Nothing like a failed reverse lockout to add excitement to your day. I saw a video awhile back of a high powered Honda doing a 1st-2nd-1st shift down the strip. It did quite an impressive reverse wheelie. 2 2 Quote Link to comment Share on other sites More sharing options...
Roman Posted April 20, 2022 Author Share Posted April 20, 2022 Altezza gearbox is super annoying for this sort of thing, Reverse is off to the left, and up. So sometimes you're in third trying to get down to 2nd, and you push it right across out of the gate and try shift down into nothing there. Bloody annoying! Quote Link to comment Share on other sites More sharing options...
ajg193 Posted April 20, 2022 Share Posted April 20, 2022 Just be happy you don't have a box with synchronized reverse Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted April 21, 2022 Author Popular Post Share Posted April 21, 2022 Flat shifting is sorted, and I got my better shift light arrangement working again, after lots of head scratching. I've also been curious about what sort of suspension settings work well for a FWD drag car, generally speaking. It turns out that a lot of the top level cars have just got completely solid suspension, or close to it! Watching some youtube videos of launches in slow motion and it looks like they do get the intitial tyre bounce and then a fair bit of wheel spin off the line. However it also seems that since any weight transfer is not beneficial, the best thing is to just get the front and rear center of gravity as low as possible. I cant see how there's any anti dive / anti lift type stuff going on that's going to get worse by lowering it. More camber wont help, but it wont have increased by much. So will give it a go with lower heights. I wound all of the suspension right down to the limit of spring travel. Then had the guard to floor distance measured on all 4 corners on flat area in the shed. This obviously isnt as good as using corner scales, but still better than nothing. With the driver and engine both on the same side in a light car, results were uneven by quite a bit. The front right dipped 15mm, and rear right dipped 10mm lower than the other side. With some fiddling I managed to get the fronts both to the same measurement, and the rears 5mm difference. It will be interesting to see if there's any improvements in grip off the line this way. Fingers crossed that the weather gods are happy for drag racing to proceed tomorrow! 12 1 Quote Link to comment Share on other sites More sharing options...
Beaver Posted April 21, 2022 Share Posted April 21, 2022 The Honda guys seem to run big weights/steel plates etc up front. Maybe only cause they have stripped weight out of the rest of the car. Who knows. Science 1 Quote Link to comment Share on other sites More sharing options...
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