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Pod Practice?
- Thread starter johnymd
- Start date
johnymd
Club Member
Just got back and the good news is, the cars still in one piece. Not a satisfying day as the car didn't run well at all, plus I just couldn't get my starts right. The first couple of runs without we're without nos and showed the increased hp with a high terminal speed. I did get some reasonable times, which surprised me, as the car had what felt like a misfire with lots of hesitating. This was in all the runs, with some worst than others, as can seen in the variation of terminals. I'll have to do a bit of head scratching to work out why it's happening but will probable start with the plugs. As usual, all advice welcome and I've attached the time slips for those cleverer than me to analyse.
Attachments
Ian
Club Member
Are you finding it hard putting the power down or is it just the launching?
What width tyres are you running? I'm trying to work out how much power I should run with mine, not really sure how much power I can put down with 245/45/16 R888's which is what I plan to run if I fit arch flares, at the moment I have 225 R1R's which I'm sure won't handle more than 400hp.
Times don't seem bad if you had some running problems.
What width tyres are you running? I'm trying to work out how much power I should run with mine, not really sure how much power I can put down with 245/45/16 R888's which is what I plan to run if I fit arch flares, at the moment I have 225 R1R's which I'm sure won't handle more than 400hp.
Times don't seem bad if you had some running problems.
John, well done on some great runs again. Am I missing something - how did you win that 5th run?
Alphabettispaghetti
Club Member
The other fella gave him a 4 sec head start!
That was good of him
I've looked in more detail now and understand - John should have said that the other guy passed him after the line at 160mph, not near the end.
johnymd
Club Member
I didn't really beat him but according to the time slip, I went across the finish line first 
It wasn't so much a problem getting the power down, just managing it off the line. You can't fead all the power in at once as you will just spin the tyres so I tend to slip the clutch for the first 10ft and keep the revs up so I'm not off the power band. It's a juggling act that on some days I just can't get right.
The main problem was with the car seaming miss or not have enough fuel in the second half of the run. I had this happen most of today but managed a couple of 11.2 runs with one at 130.98mph. I'm starting to think it may be a fuelling issue with the pump not quite keeping up with demand. Still open to suggestions though.
It wasn't so much a problem getting the power down, just managing it off the line. You can't fead all the power in at once as you will just spin the tyres so I tend to slip the clutch for the first 10ft and keep the revs up so I'm not off the power band. It's a juggling act that on some days I just can't get right.
The main problem was with the car seaming miss or not have enough fuel in the second half of the run. I had this happen most of today but managed a couple of 11.2 runs with one at 130.98mph. I'm starting to think it may be a fuelling issue with the pump not quite keeping up with demand. Still open to suggestions though.
johnymd
Club Member
Do you need to take it the day before you expect to have a bad run. If you are haveing a few and expect the bad luck to continue can you then take some to help the next run? Should I have a break to give it time to work? I wish I'd asked for some in the shop now as it sounds like it could have improved my week end.
Never ceases to amaze me how helpfull forums can be.
Never ceases to amaze me how helpfull forums can be.
johnymd
Club Member
Done a bit of research and found some guide figures for injectors. They say roughly 1hp per cc is the limit. So my 370cc injectors will max out at 370hp. I'm making around 400 so could this be what I'm feeling. There's also mention that you get issues when you run over 80% duty. May try fitting my 440 injectors I bought a couple of years ago!
johnymd
Club Member
Tyres are 225's. With more width you should in theory have at little more traction. Once you get over 300 or so HP it becomes harder to get off the line well. I can lauch better without the nos as the reduction in power makes it easier. With nos , you have to slip the clutch and fead the power in. Its a fine line between too much wheel spin and boggin down. I am fortunate that I have a wide power band and enough lowdown torque, plus virtually no lag, that if it does bogg down it picks up pretty quick. To begin with, I think the more power you have, the slower your times will be untill your starts improve. There were a few people I spoke to over the weekend who were running 550+HP in car not that much heavier than mine, who were stuck in the mid 13's. They kept asking me how they could improve. The easyest way would be to reduce the power to around 320 and the 12's should come easy. Then progress to more power as you become more skilled at launching. The other option is to build a relatively high power engine and use some clever electrinics to manage the power for you.
I was listening to a driver of a 1600hp skyline telling his engine mapper that his time were slow because the car was spinning its wheels too. He instructed him to fix this before his next run then left this young guy tapping away on his laptop to manage the car owners next run. The driver just wanted to sit at the line with his pedal on the floor, press a button when the lights change then brake at the end of the track. Where's the fun and skill in that? OK, its probable not quite like that as the runs did look a bit scary, all the way to the line. But the power can be managed with electronics. Just depends what you want to spend.
Great build by the way and cant wait to see it used in anger.
I was listening to a driver of a 1600hp skyline telling his engine mapper that his time were slow because the car was spinning its wheels too. He instructed him to fix this before his next run then left this young guy tapping away on his laptop to manage the car owners next run. The driver just wanted to sit at the line with his pedal on the floor, press a button when the lights change then brake at the end of the track. Where's the fun and skill in that? OK, its probable not quite like that as the runs did look a bit scary, all the way to the line. But the power can be managed with electronics. Just depends what you want to spend.
Great build by the way and cant wait to see it used in anger.
Simple question but perhaps not a simple answer (I'm not very knowledgeable on modern electronic cars) :
On the 350Z the manufacturer had set the software to limit power in the lower 3 gears as far as I remember. This was to make driving safer and smoother. I had mine changed to give more power and response (UpRev software).
Is this the area of software that you mean John or is there other mapping changes too? Does your car know what gear you are 'in'?
On the 350Z the manufacturer had set the software to limit power in the lower 3 gears as far as I remember. This was to make driving safer and smoother. I had mine changed to give more power and response (UpRev software).
Is this the area of software that you mean John or is there other mapping changes too? Does your car know what gear you are 'in'?
johnymd
Club Member
Mine has no electronics to limit the power through the gears. The GTR I was talking about and many other ECU's for that matter can mapped for gear/revs and have launch control and boost control fascilities. You can have switchable maps for say, road, track or drag. The possibilities are almost endless if you have the budget to support it. The 1600hp GTR would probabley be imposible to drive without it.
The point I was getting at, in answer to Ian's question: "can my car make use of any more power" was that no I couldnt but it is possible with the budget to spend on driver aids.
The point I was getting at, in answer to Ian's question: "can my car make use of any more power" was that no I couldnt but it is possible with the budget to spend on driver aids.
andrew muir
Club Member
Ian
Club Member
Impressive times considering 225's, should have no problems with 245's then.
Good answer also, I'm going to be running boost by gear so that should help greatly. I'll also have a switch on the dash to change between two power settings, thinking a 400hp setting and a 550hp setting.
Good answer also, I'm going to be running boost by gear so that should help greatly. I'll also have a switch on the dash to change between two power settings, thinking a 400hp setting and a 550hp setting.