MB goes racing 2017
12-26-2016, 02:17 PM
#11
Registered User
So the plan is to salvage the head but get a new short block built which can be made up to take up the loss of meat on the head. This would probably be by tweaking piston heights as these would be custom made.
I will also be ditching the oem water pump and going electric, but will need a bigger battery as the plan is to run the pump post race with the engine off.
The sequential box is bought and paid for, however there are a lot of install costs. The ratios are quite long for an NA race car, so it really needs a 5.1 final drive, but you can't get them anymore. A 4.77 will be ok but I will probably need to get shorter 4/5/6 from Quaife and that's not cheap on top of the 4.77 diff rebuild. Gears 1/2/3 are fixed and Quaife don't offer alternatives, so can't touch them. Today though I found a 5.38 final drive and it's on it way from the US, so that very exciting and will make the gear ratios perfect 
I haven't updated the spreadsheet for the 5.38 but below gives an idea of the ratios (second set of columns is with the shorter optional 4/5/6 that Quaife offer, but I won't need these now.
I haven't updated the spreadsheet for the 5.38 but below gives an idea of the ratios (second set of columns is with the shorter optional 4/5/6 that Quaife offer, but I won't need these now.
The sensible thing to do here is basic engine build and keep the oem box but I know I will struggle to be sensible. Always wanted a sequential in the S but there are some unknowns with it. I'd also be replacing the entire drivetrain of engine / box and diff so would need a couple of test days to get comfy with it. Other pita is bedding the engine in. Needs to be done on the road prior to mapping, so need to get the car motd. Or a full day on the dyno, then oil change and then mapping. Just a taste of the volume of logistics this sort of thing involves and what Urge have cost me.
I've also been looking at grip and going to a 10" front and rear with a wider track. Really just to improve the front, but running 255 on a 10" will also be a good thing. Toyos max tyre size in 17" is 255 so 10" is as big as I need to go. I would need wider front arches and probably rear, so looking at Downforce fronts and ASM rear arch things.
As always, best of luck in the forthcoming season, I'll try to pop along but the nearest event is Silverstone which is a 2hr drive!
12-26-2016, 02:47 PM
#12
Member
Thread Starter
Hi Ron,
I know what you mean with the engine, and I was in the same place as you but the engine builder in using won't touch anything he's not sure on and after a lot of discussion we went with keeping the head. There's been a lot of discussion on options (a lot of it new to me) but he will stand by the solution.
On the box, at somewhere like Donny it's 1-2 seconds a lap. I ran the Caterham there as a manual then put the Sadev in and went back a few weeks later and it was just under 2 seconds in that. You can see on the data log, every upshift eats up fractions of a second as there's zero deceleration. There's also no shifting errors and no risk of an over rev as an added bonus.
I've spoken to a few of the proper US track and race guys, and there's some pretty hard data on the effect of running a 255 on a 10" wheel being quicker than the same tyre on a 9". Even if that's discarded as a point, for me to go to a 9" front means a new set of wheels - unless I went unmatched but that looks gay so when you then look at new sets you might as well go higher on the offset and gain some track too.
Will look up that Daihatsu alternator too!
All the things I'm looking at have been pored over in detail for months (as I like to do!) so hopefully it's a good direction. There's some very trick cars in the Championship now so it's one you always have to look at improvements.
I know what you mean with the engine, and I was in the same place as you but the engine builder in using won't touch anything he's not sure on and after a lot of discussion we went with keeping the head. There's been a lot of discussion on options (a lot of it new to me) but he will stand by the solution.
On the box, at somewhere like Donny it's 1-2 seconds a lap. I ran the Caterham there as a manual then put the Sadev in and went back a few weeks later and it was just under 2 seconds in that. You can see on the data log, every upshift eats up fractions of a second as there's zero deceleration. There's also no shifting errors and no risk of an over rev as an added bonus.
I've spoken to a few of the proper US track and race guys, and there's some pretty hard data on the effect of running a 255 on a 10" wheel being quicker than the same tyre on a 9". Even if that's discarded as a point, for me to go to a 9" front means a new set of wheels - unless I went unmatched but that looks gay
so when you then look at new sets you might as well go higher on the offset and gain some track too.Will look up that Daihatsu alternator too!
All the things I'm looking at have been pored over in detail for months (as I like to do!) so hopefully it's a good direction. There's some very trick cars in the Championship now so it's one you always have to look at improvements.
12-26-2016, 11:04 PM
#13
At last, an interesting thread update on S2ki! Been bored at the in-laws for a few days. Keep it up, MB!
12-27-2016, 12:56 AM
#14
Always interesting reading. Good luck which ever way you go with transmission. One design class racing is always fun as it focuses on the driver (I used to race a couple of one design sailracing craft) but you have nothing to change, personalise or improve on. Get in the S and surprise them in the new series, you know you want too.
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12-27-2016, 01:00 AM
#15
I guess the only thing to watch out for is wheel weight and how the steering will feel with that much of a bigger wheel up front - You might just about get away with the rears on the right offset, the fronts are def going to need arches - get the wings from a wide body kit?
12-27-2016, 01:26 AM
#16
Member
Thread Starter
Thank chaps.
Nomad, my rears are currently et60 with a 255 tyre, so going to an et50 on the same size tyre would mean 10mm increase, or 5mm either side. The unknown is going from a 9" to 10" will bring the tyre out further than that. Load of pics on the forum where people have them on std arches (but rolled) but mine are already bloody tight as the car is so low.
The fronts would pretty much be a lost cause with standard arches I think. Again I've seen a lot of pics where people have done it but mine are so tight even on an 8" with 235s.
Needs to comply with this too:
The top of any tyre must not protrude outside of the wheel arch when in straight ahead position
The tyre must not be visible when viewed from above. When viewed from the rear, the tyre must not be visible above any point 50mm or more above the axle centre line. MSA Yearbook
Nomad, my rears are currently et60 with a 255 tyre, so going to an et50 on the same size tyre would mean 10mm increase, or 5mm either side. The unknown is going from a 9" to 10" will bring the tyre out further than that. Load of pics on the forum where people have them on std arches (but rolled) but mine are already bloody tight as the car is so low.
The fronts would pretty much be a lost cause with standard arches I think. Again I've seen a lot of pics where people have done it but mine are so tight even on an 8" with 235s.
Needs to comply with this too:
The top of any tyre must not protrude outside of the wheel arch when in straight ahead position
The tyre must not be visible when viewed from above. When viewed from the rear, the tyre must not be visible above any point 50mm or more above the axle centre line. MSA Yearbook
12-27-2016, 06:25 AM
#18
Yeah you are definitely not fitting an 10" wheel with 255 tyre upfront without new arches. Will the rear overfenders comply with the regs?
Like you I've read hundreds, if not thousand of threads on the board and all the information is there.
Have you spoken to anyone who runs the 10"/255 upfront with the arches you are looking at? You want decent geo and to be able to mount a kerb without the arch (or engine if your endy) disintegrating
I also do believe that you will gain up to 2 seconds per lap with the new box if setup correctly. I friend of mine who I do trackdays with proved this at Cadwell in November. In all the previously days he would never be able to pull away on the main straight, but last time he did.
Like you I've read hundreds, if not thousand of threads on the board and all the information is there.
Have you spoken to anyone who runs the 10"/255 upfront with the arches you are looking at? You want decent geo and to be able to mount a kerb without the arch (or engine if your endy) disintegrating
I also do believe that you will gain up to 2 seconds per lap with the new box if setup correctly. I friend of mine who I do trackdays with proved this at Cadwell in November. In all the previously days he would never be able to pull away on the main straight, but last time he did.
12-27-2016, 11:09 AM
#20
I like Thruxton, might truck down again. Distant though it is - any chance of a hook up?
As noodles says shame no Snet but the first two are within range for me though early season and I am thinking you are planning a fair lot of changes so early season might not be the time to see your normal reliable faultless running. But hey what do I know? From what you say the past has been a bit like watching swans glide by - they appear effortless but they are paddling like f*ck under the surface
p.s. don't mention the football or I won't be coming. So there's a choice eh?
