Jump to content

Recommended Posts

Posted

Haha, there's a few things to it.

1. First day driving my car at Teretonga and only my second day ever on that track. 

2. 200/580-15 slicks are a bit too small really. The City runs 235s. 

3. Aero def helps in turn 1, 2, 3 

4. My car jumps over the braking bumps and the City is way more setled. I'll. Be able to dial that out with some setup work

5. I had a flu and was just kinda not there, but still gave it a good crack

I could go way faster round turn 1 too, it's just scary braking on an angle from 200kph over bumps into a looooong radius corner :lol:

 

  • Like 5
  • 4 weeks later...
  • Replies 898
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted

Congrats on the win!

That looks like a really fun track, I've never seen it used before, very cool with the elevation changes.

Glad you came out of it unscathed, there was more then a few moments where I was wondering what the other cars were going to do, some of them seemed very focused on in front of them.

  • Thanks 1
Posted

+1 to elevation changes looking like heaps of fun. 

The elevation changes at Hampton are cool, but they're a bit more gradual 

Well done on pedalling to 1st and 2nd to the HPA lads! 

How good! 

I am super stoked to see the car back out there getting shit done. 

  • Thanks 1
Posted
1 hour ago, Hyperblade said:

I was wondering what the other cars were going to do, some of them seemed very focused on in front of them.

Club sprints are like that eh... People forget to look backwards, no matter how much you talk to people and they agree to move out of the way. It was fun though! Even though the traffic killed a couple of runs for ultimate times. 

1 hour ago, Roman said:

Well done on pedalling to 1st and 2nd to the HPA lads! 

How good! 

I am super stoked to see the car back out there getting shit done. 

Cheers man, it's a nice feeling to be back out there. Looking forward to more events over summer.

  • Like 3
Posted

Incar from city is great. That lockup was a massive save from the outside, even though it looked pretty tame from incar. 

 

Very close times. Branden might have had you with bit more commitment over the top of the bridge :wink: Interesting to compare low vs high downforce car handling characteristics. You being able to 'float' the 86 into a corner while the city is point-and-shoot. 

 

 

 

  • Thanks 1
Posted
1 minute ago, Rhyscar said:

You being able to 'float' the 86 into a corner while the city is point-and-shoot. 

It's a good battle eh. Reminds me of racing your old man in the Corolla and having almost exactly the same laptimes, but different speed in lots of areas. 

My car was geared just right for that track, so I was able to launch out of the corners better. The City is loads quicker down the hill into the carousel.... We both hit a top speed of ~150 on the front and back sections of the track, so peak horsepower/speed seems about the same. 

Pretty keen to go door to door racing against the City. We should get a chance to battle at Highlands later in the year. 

  • Like 2
Posted
2 minutes ago, Truenotch said:

It's a good battle eh. Reminds me of racing your old man in the Corolla and having almost exactly the same laptimes, but different speed in lots of areas.

 

Reminds me of this old gem.

 

  • Like 1
  • Thanks 2
Posted
3 hours ago, yoeddynz said:

What was the imps setup in that race? it did pretty well! 

The Imp has a blacktop 4AGE in the front. It goes extremely well.

Imp purists hate it.... you two would probably get on well :lol:

20230422_155515.thumb.jpg.77b63a751810f27b45a77ba62cf39a65.jpg

20230422_155600.thumb.jpg.86fd79057e8c68f9bb65ca6a8ed76b29.jpg

  • Like 5
  • Haha 4
  • 1 month later...
Posted

Try an extra 100mm  on top of what you have,  if you can fit it.   then move 20mm at a time either side.   vvti  can shuffle things a bit.  but getting the intake length dialed is still worth it.   
My long intake (compared to what everyone else runs)   still works best, even revving to 10k with vvti 
See how it moved the bumps up the rpm range with the with the shorter runners.    going longer should pull a stronger one thats currently out of reach  down the rpm range,   try get that to bang on where it wants to naturally make peak power.  then use the  vvti to hold the peak longer.    you will likely find if you only go say 50mm longer than current. it may get worse before it starts to get better

  • Like 1
  • Thanks 2
Posted
15 hours ago, kpr said:

Try an extra 100mm  on top of what you have,  if you can fit it.   then move 20mm at a time either side.   vvti  can shuffle things a bit.  but getting the intake length dialed is still worth it.   
My long intake (compared to what everyone else runs)   still works best, even revving to 10k with vvti 
See how it moved the bumps up the rpm range with the with the shorter runners.    going longer should pull a stronger one thats currently out of reach  down the rpm range,   try get that to bang on where it wants to naturally make peak power.  then use the  vvti to hold the peak longer.    you will likely find if you only go say 50mm longer than current. it may get worse before it starts to get better

Wicked, thanks. My instincts keep telling me to go longer after watching your developments. We might need to model some curvy boiz to get an extra 100mm. I'll see if Connor can print some that can be chopped back easily for testing.

The Jenvey ITBs we have here are only 48mm, with a 51-45mm taper through the body, so I'm not sure how much better they'll be than blacktop ITBs yet. Have you played with the distance between the head face and throttle butterfly? I'm thinking of mounting the throttles really close to the ports to counteract the size of them (and try to make them act like a 50mm+).

  • Like 1
Posted

Yeah dont be afraid to run run bends if need to.  long as they arent sharp wont effect power.  
haven't played with distance to head, in any scientific way anyway.   ages ago i swapped from  47mm (blacktop with bigger plates)    to 52mm throttles.   with length and  belmouths the same.   was zero difference in power.  that was running at around the 150kw mark.  

Going to throttles too big and loosing power seems like a bit of a sharn to me.  can gain power in the bottom end going to a smaller runner.  but will loose top end power before that happens.   not what you want for race car.

I would think the 45's would be starting to get borderline with the power you are making, but maybe ok.    those 48's should be  plenty big enough step up,  they have probably taken the area  the throttle plate takes up into consideration, with the 45mm outlet.    the roman dave spec bmw bike throttles are the same  48mm plates and 45mm outlet

 

  • Like 1
  • Thanks 1
Posted
2 hours ago, kpr said:

The roman dave spec bmw bike throttles are the same  48mm plates and 45mm outlet

Slightly off.

53.52mm entry  (2249.69 mm2)

45x42.52mm exit (equivalent of 42.84 diameter circle) but I believe the exit can be bored to 46mm without changing throttle plate (Unconfirmed)

 

For what it's worth re sizing for k20 recommend from someone who has Dyno tuned a lot of racecars was 48mm jenvey. Larger were just not as good according to them. I also know someone here who dropped their kinsler itb size down to 48mm from like 52 and it performed better (4p head)

 

Jenvey 48mm have 2 degree taper and 46mm exit

Posted

ah yep, i was probably remembering what i was gonna die grind them out to..  

Smaller intake covering up a bad exhaust side is also a thing.      I'd  try run smaller header primary's before making the intake smaller. 

 

 

 

 

  • Like 1
Posted
1 hour ago, Hyperblade said:

For what it's worth re sizing for k20 recommend from someone who has Dyno tuned a lot of racecars was 48mm jenvey. Larger were just not as good according to them. I also know someone here who dropped their kinsler itb size down to 48mm from like 52 and it performed better (4p head)

Interesting. We'll be using 50mm Jenvey on the K20 at work and also have these 48s for a back-to-back test. I'll ask the guys to make a video about it when we get to that stage.

Terry Radbourne from Bourne HPP in the UK said "bigger isn't better" but wouldn't say the size he uses on their K20s over there... Just that he'd found a sweet spot that suits his builds.

 

  • Like 2
  • Thanks 1
Posted

I guess an intetesting datapoint is that if you look at almost any motor that transitions from cable to ethrottle. They end up with bigger throttle(s)

As you can just reshape the opening rate to get around drivability issues at low rpm. Where 30% throttle might give you 90% of airflow.

  • Like 2
Posted

driveability  wise, oversized throttles kinda suck.   unless run non linear  opening rate. cant say ive seen bigger perform worse though

another interesting thing, slightly off topic.     if you run an itb car up at say 90%   even oversized throttles.   it will loose some power.    but oversized single not so much.  was tuning a 2zz the other day with big single e-throttle 70% was the same power as 100%,  it needed to go down to 50% before it would loose 10kw.       It seems like  the angle of the  itb throttle plate screws up the  runner tuning. 

  • Like 3

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...