Rover with a turbo, or: How to build a reliable turbo track car. SPM S1, NASA ST3/4
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
I will post the Sunday race video later this week. Saturday video is pretty boring, just me picking my way through traffic and managing the gap to P2. I may throw up the 47.3 lap, but it's not that impressive of a time TBQH. The track was a solid 2.5-3sec off where it was when I was there in November. I had a 46.0 back then on a 225 RC-1, and nobody bolts on 245 R7s and loses 1.5 sec. The other class times reflect that - everyone was way off the pace, even the fast guys.
Reply
0
0
Reply
0
0
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
To clarify, that's not an optimized spark map. There is no dyno/tune time on this setup, just some tweaks during the first couple of events to get the AFRs where I wanted them. I'm sure there's power on the table but the car already makes a little too much for ST4 and is perfect for S1 so I had no motivation to spend time trying to make more power. I have been waiting for some spare time to get some Fuelab bits and a flex fuel sensor installed, since I want to have a ~275whp E85 map for this car, but that whole "time" thing just hasn't materialized this year. I will get that all done before I put it on a Dynapack for a proper dial-in.
Reply
0
0
Junior Member
Joined: Jan 2017
Posts: 149
Total Cats: 3
From: Victoria BC
I have seen dyno graphs 300fllbs at 4000 rpm with that setup and pump gas.
S1 leaves a bunch of power on the table for drive line reliability and to add accessibility/affordability to the class.
Looks like an electric beast Savington!
How is the throttle response?
Last edited by nbfather; May 25, 2017 at 04:41 PM. Reason: Premature typulation
Reply
0
0
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
Kinda freaky. With the old 2871R in Theseus you had to drive it like a turbo car the entire time. Always 10-15% TPS, always pre-spooling the turbo. With this, the only corner at Sonoma I felt like I had to do that was T11, where the car is dropping down to ~4000rpm or so in 3rd gear. Even there, the throttle response was good enough that I was throttle-steering on exit up to the concrete wall on qualifying or TT laps. Every other corner, even T2 where I'm coming off at ~4600rpm in 4th, feels perfectly linear. It doesn't have to be driven any differently from any other car, since the turbo responds and comes onto boost so smoothly and quickly.
To quantify it, from 5000rpm, if you roll from 0% to 100% TPS in 1.0 seconds, the car is at full boost before your foot hits the floor.
To quantify it, from 5000rpm, if you roll from 0% to 100% TPS in 1.0 seconds, the car is at full boost before your foot hits the floor.
Reply
1
1
Joined: Apr 2014
Posts: 18,643
Total Cats: 1,870
From: Beaverton, USA
Someone at autox asked me if it was a kswap. Had a bunch of people who were blown away when I said turbo. It drives like a bigger motor.
And I have a 6758, not a 6258
And I have a 6758, not a 6258
Reply
2
2
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
I've driven both a bunch now, and if you can believe it, the 6258 is noticeably better than the 6758. Not a lot, but noticeable. For its size and power potential the 6758 is insanely good, but definitely hits a little harder than the 6258. The 62 is just buttery smooth and almost completely linear.
Reply
0
0
my 6258, but I often wonder what the 67 is like. I need to drive something with a 67 in it so I can compare.
Reply
0
0
Junior Member
Joined: Jan 2017
Posts: 149
Total Cats: 3
From: Victoria BC
Do you get any video of the event?
I bet the car is a bit of a handful...My kind of car!
Your car sounds like way too much fun!
Reply
0
0
Junior Member
Joined: Jan 2017
Posts: 149
Total Cats: 3
From: Victoria BC
Kinda freaky. With the old 2871R in Theseus you had to drive it like a turbo car the entire time. Always 10-15% TPS, always pre-spooling the turbo. With this, the only corner at Sonoma I felt like I had to do that was T11, where the car is dropping down to ~4000rpm or so in 3rd gear. Even there, the throttle response was good enough that I was throttle-steering on exit up to the concrete wall on qualifying or TT laps. Every other corner, even T2 where I'm coming off at ~4600rpm in 4th, feels perfectly linear. It doesn't have to be driven any differently from any other car, since the turbo responds and comes onto boost so smoothly and quickly.
To quantify it, from 5000rpm, if you roll from 0% to 100% TPS in 1.0 seconds, the car is at full boost before your foot hits the floor.
To quantify it, from 5000rpm, if you roll from 0% to 100% TPS in 1.0 seconds, the car is at full boost before your foot hits the floor.
Did the car feel quite a bit stronger after the tune to S1 specs?
Did you ever get that backfire sorted out?
Sounds cool, but that **** would keep me awake at night!
I was wondering if you had a leaking injector?
Reply
0
0
Junior Member
Joined: Jan 2017
Posts: 149
Total Cats: 3
From: Victoria BC
Reply
0
0
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
There is no dyno/tune time on this setup, just some tweaks during the first couple of events to get the AFRs where I wanted them. I'm sure there's power on the table but the car already makes a little too much for ST4 and is perfect for S1 so I had no motivation to spend time trying to make more power.
Did you ever get that backfire sorted out?
Sounds cool, but that **** would keep me awake at night!
I was wondering if you had a leaking injector?
Sounds cool, but that **** would keep me awake at night!
I was wondering if you had a leaking injector?
Reply
0
0
Reply
0
0
