NASA ST4 - U build thread - engine swapped

[gt5759]

Originally Posted by smoltz

You doing this yourself? Cagekits? A cage is on my post-season to-do list, trying to figure out options.

Been doing this work for over 20 years now! I do highly recommend cagekits for a kit, best one I have ever seen. Can't go wrong, just make sure your confident in your welding abilities.

[smoltz]

Originally Posted by gt5759

Been doing this work for over 20 years now! I do highly recommend cagekits for a kit, best one I have ever seen. Can't go wrong, just make sure your confident in your welding abilities.

Wow!

[blsfrs]

Originally Posted by gt5759

Sure did, went through all the options before locking down on this one but a lot of people don't realize how important that is for a racing application!

Just out of curiosity, what is the critical speed of your new driveshaft? I know from experience the standard DSS al shaft is just over 100mph.

[gt5759]

Originally Posted by blsfrs

Just out of curiosity, what is the critical speed of your new driveshaft? I know from experience the standard DSS al shaft is just over 100mph.

Not sure what size shaft that would be at 100mph?
This is 3.5" diameter 45" long, 0.125" and at the length that i have its about 10285 rpm for critical speed. At 200 mph it would put shaft speed at 10487 with my gearing and tire size.

[blsfrs]

This was my experience with a DSS al driveshaft.

https://www.ft86club.com/forums/showthread.php?t=148537

[gt5759]

Originally Posted by blsfrs

This was my experience with a DSS al driveshaft.

https://www.ft86club.com/forums/showthread.php?t=148537

That was definitely a long bad deal, appears they didn't do the math correctly. Rather long shaft to make only 3", there is a reason the OE is two piece at that length/size. Minimum should have been 3.5" but really it needs a 4" at that length for anything performance related (don't think it would fit though). They make high quality parts but if the math/design is wrong, it doesn't matter how nice it is!

Speaking of shafts our new one arrived and looks perfect. Should get her all fixed up this weekend and be ready for OIR next week!

[blsfrs]

Originally Posted by gt5759

That was definitely a long bad deal, appears they didn't do the math correctly. Rather long shaft to make only 3", there is a reason the OE is two piece at that length/size. Minimum should have been 3.5" but really it needs a 4" at that length for anything performance related (don't think it would fit though). They make high quality parts but if the math/design is wrong, it doesn't matter how nice it is!

Speaking of shafts our new one arrived and looks perfect. Should get her all fixed up this weekend and be ready for OIR next week!

After a run, it might be interesting to get the temperature of the driveshaft at its closest point to the exhaust. It might give you insight as to why the CF shaft failed.

[gt5759]

Originally Posted by blsfrs

After a run, it might be interesting to get the temperature of the driveshaft at its closest point to the exhaust. It might give you insight as to why the CF shaft failed.

We did just that this last event, it gets to about 190* on the surface via temp strips. that's hot enough to cycle the resin and cause problems. So i feel we have our answer!

[gt5759]

Well, OIR did not go as planned. Car was doing fantastic but I ended up getting sick severe dehydration is no joke, ended up going to the ER for severe abdominal pain after getting back home (thought my appendix burst or gallbladder. Point of the story, take care of yourself and be hydrated well before the event - I was not and had been pushing way to hard for weeks and not taking care of myself - something I never had problems with before but I'm not 20 anymore and need to remind myself of this sometimes.

Everything on the car felt so good, its working so well. I just need more seat time. Highly frustrating I couldn't race but it wouldn't have been safe for myself or others.












On to the next!!

[gt5759]

Last race of the season!

Sadly, we didn't get to run much this year from a variety of things, some car related some not, but we did get the information we needed to make the right improvements over the winter. She feels really good and is heading in the right direction, which is the big thing. Sorry for the lap video being far from the best in not only video quality (exposure and data overlay not working right yet) and drive mod!

Only major change to be made this off season is a larger fuel tank. Which I had to get approved by national to put it behind the driver like the gr86 cup cars do. She's a little thirstier than I figured and only going to get worse the faster we get. Other changes are small - aluminum knuckles from a 22 brz, send the shocks to MCS to re-valve and alignment updates.

Very happy with the car, glad I made the choice to switch over from the miata.

[smoltz]

Originally Posted by gt5759

Only major change to be made this off season is a larger fuel tank. Which I had to get approved by national to put it behind the driver like the gr86 cup cars do. She's a little thirstier than I figured and only going to get worse the faster we get. Other changes are small - aluminum knuckles from a 22 brz, send the shocks to MCS to re-valve and alignment updates.

Very happy with the car, glad I made the choice to switch over from the miata.

Amazing build, sorry to hear you didn't get to use as much as you hoped this season.

I had emailed national about if the GR86 cup setup was okay as they are now saying that you need a bulkhead which the GR86 cup car doesn't have.

I don't have a GR Cup, but was thinking about doing the seam as the Gr86 cup but I think I am now just going to build a bulkhead where the trunk is and put the fuel behind that.

I see you have a custom dash, is that the HGK one? Or something else?

[gt5759]

Originally Posted by smoltz

Amazing build, sorry to hear you didn't get to use as much as you hoped this season.

I had emailed national about if the GR86 cup setup was okay as they are now saying that you need a bulkhead which the GR86 cup car doesn't have.

I don't have a GR Cup, but was thinking about doing the seam as the Gr86 cup but I think I am now just going to build a bulkhead where the trunk is and put the fuel behind that.

I see you have a custom dash, is that the HGK one? Or something else?

That should work well too, biggest I could fit back there due to the subframe is 14 gallon. A 10 gallon would enough for sprint racing with the FA or K series. This little piggy gets 4 miles to a gallon on E85.

Fiberglass HGK piece. Expensive, but really good looking and very light.

[redlined600]

If you're de-tuning for P:W anyway, why not just run 91oct?

[Midtenn]

Originally Posted by redlined600

If you're de-tuning for P:W anyway, why not just run 91oct?

E85 combustion temperatures are lower, which means less heat in the cooling system. So, it is likely to keep the cooling load down.