My bet is because drag is proportional to velocity squared. So more power means more acceleration at higher speeds.

 

Basically, a 300hp / 23xx lb car is already the lowest power/lowest weight car on the grid in a class like TT2. So the car is outgunned on the straights. Restricting power to hit the hp/wt target would exaggerate that weakness.

 

I understand the math in this but it would be interesting to do a back to back.

I myself would feel much happier about dropping 75lbs than gaining 13hp.

 

For TT, it's probably a toss-up and/or track-dependent. For w2w, ballast up and run full power. Passing on straights (or at least keeping from being passed) is way easier than passing in the corners.

 

It would be interesting to test back to back. There's the old adage that horsepower helps on the straights but weight matters everywhere. At ACS, I'd be ballasting up as much as possible. Elsewhere it's likely closer. I don't yet know the final race weight that I'll end up with the new drivetrain but this may be something I'll have to test.

 

Also, its not 100% linear either....

if you tune down, you can shape the torque curve better, and obviously you would save on consumables (tire wear) also..

Maybe max power for qualifying and light weight version for the races - specially long ones?

 

No wheel to wheel for this car. Time Attack is always qualifying

 

Have you tried the lf4 turbos yet?
same bolt pattern?

 

NASA has an average horsepower rule now, so curve shaping is regulated and therefore necessary in either config.

Vise-versa will be preferred.
IF the heavier/higher power config isn't outright faster for both, it WILL be better in a race against a corvette. /nomorew2wtheory.

 

Haven't physically bought one and fitted it up but it's the right bolt pattern. Looking at the space, notches (likely big-ish ones) would be needed in the frame rails to clear.

As "easy" as it would be to bolt up a pair of those turbos, if I were to boost this motor I don't think I would go turbo. Twin turbo is heavy. In the back of my head where I'm always looking far down the road a Rotrex has been high on the list because this motor already makes great torque, and it would be lighter and simpler than twin turbo. But that is FAR down the road, if ever.

This isn't a "you heard it here first, Ryan's going to boost it" post. I'm QUITE excited to enjoy the naturally aspirated simplicity for a long time. The goal here is to hit my power target with a very reliable package so I can turn attention to developing other areas further rather than have a drivetrain I have to babysit and fiddle with. Once it's on its feet I have a whole new evolution planned for the aero package for example. For now though, I just can't wait for it to be running

 

Excellent build thread. On the topic of LFX powertrains. I know a school that will sell the entire LFX powertrain for the 2015 Camaro(no more than 50 miles on it) for a lot less than you all are paying for it. Let me know if anyone is interested and I can provide the contact information. Sorry to hijack thread just wanted to help anyone interested. PM me instead of responding so we don't mess this thread up. Thanks!

 

If the Radium dry breaks were the appetizers, the entrees just showed up

Staubli -10AN dry breaks for the oil cooler lines:



By themselves they don't seem too large, but once you add a pair of hose ends the assembly is like 7" long. It's actually rather difficult to figure out where to fit these in. After some re-working of some plans I think I have it figured out. Have to order yet MORE fittings to make the new config work, but I THINK this will conclude the many, many rounds of fittings orders.

Aside from doing a bunch of re-puzzling on that front, I did get a few lines hammered out yesterday. I'll try to do a more comprehensive post about the line layout for each system once I have them all done but here's some random pics for now.

Power steering from rack to cooler in, including in-line dry break:



Oil line from engine to remote filter, with fire sleeve:

 

Is that a Koul Tool?

 

Affirmative. Handy little things that make the assembly process much easier.. only issue I've run into is some mfg's hose ends are a hair too long for the tool.

 

You're getting close. I'm waiting for your impressions. Really interested to see what you're going to do with aero next

 

While waiting on the last fittings to arrive, this past week I've been working on wiring plans in the evenings.

Because race car I'm pulling the entire Miata harness on the chassis side as well and will make a new harness for just the essentials. For the record, if this was a street car with many more factory systems I would keep the factory harness and just add things as needed. But since that's not the case, there's some planning to be done here if I want to wire everything up in one nice clean harness.

The engine harness itself has already been set up nicely for my needs by V8R. They trimmed out anything unnecessary, converted it from auto to manual, added an OBDII port for me and extended a few wires at my request. They also fused anything that needed it and added a main relay. All that's left for me to do on that side is carry a few voltage wires from the cabin/battery over to the engine side.

But, that doesn't get me out of the woods. I still need to sort out a chassis harness which includes several systems like fuel, ignition, etc. as well as the Racepak dash plus the sensor module for the dash. I also need a cooling fan circuit, and I need to get the OBDII port and the drive-by-wire connector into the cabin. To make things easy to service/remove, almost everything will pass through a single bulkhead connector in the firewall.

One unknown I ran into during planning was the question of how much info the digital dash can pull directly from the ECU via the OBDII port. Anything the dash can get straight from the ECU saves me time and wires. The guys at Racepak couldn't make any guarantees, they said you really just have to plug the dash into the car, start it up and see what data it can pull. Well that's great except I can't start my car yet - I need the wiring done before I can start it... but if I want to do the wiring all at once and not have to hack it up and add stuff later I need to know this answer before I do the wiring. Gotta love catch-22's.

Sean had a great idea for a solution - rent a V6 Camaro and wire the dash up to it.



Turns out it can pull quite a bit of info. I don't need most of it, but here's the full list of what the dash is getting from the OBDII port - noteworthy items that I'll probably be displaying on the dash in bold:

Fuel system status
Engine RPM
Vehicle speed
Calculated engine load value
Short term fuel % trim - Bank 1
Short term fuel % trim - Bank 2
Long term fuel % trim - Bank 1
Long term fuel % trim - Bank 2
Intake air temperature
Intake manifold absolute pressure
Timing advance
Engine coolant temperature
MAF air flow rate
Oxygen sensor Bank 1, Sensor 1
Oxygen sensor Bank 1, Sensor 2
Oxygen sensor Bank 2, Sensor 1
Oxygen sensor Bank 2, Sensor 2
Run time since engine start
Distance traveled with malfunction indicator lamp (MIL) on
Fuel pressure
Fuel rail pressure (diesel)
Fuel level input
Fuel type
Commanded evaporative purge
# of warm-ups since codes cleared
Distance traveled since codes cleared
Evap. system vapor pressure
Barometric pressure
Ambient air temperature
Control module voltage
Absolute load value
Command equivalence ratio
Throttle position
Relative throttle position
Absolute throttle position B
Absolute throttle position D
Absolute throttle position E
Command throttle actuator

In addition to the above bolded items, I'm adding temperature sensors for engine oil, transmission, differential and power steering fluid. These four will tie into a Racepak universal sensor module which transfers the data from those sensors to the dash via one cable. Between the stuff above and these four added sensors the dash should be able to keep an eye on everything important. I can set up warnings on the dash for any of these inputs, so I can focus on driving rather than worrying about checking gauges.

I'm disappointed that oil pressure isn't on that list. The ECU monitors this, but it appears it doesn't send that info to the OBDII port. I'll need to wire up a second OP sensor or figure out if I can piggy-back on the factory sensor's wires. Not sure yet on that front, but overall some good info gained and I can finish up my wiring plans now.

 

At least someone had the idea in the office to RENT that Camaro. ;-)

 

Credit to the brains of the operation added

 

What sort of data rates are available from the OBD? My understanding was that the data rates were quite low, but I don't really know what that means. However, it may mean you might have to prioritise what systems you use from the OBD, and what you have to import directly. There is no canbus on the ecu?

If you are not logging, nbd - the one you want good rates on is the revs, the others can be sacrificed to lower rates.

I wouldn't bother with PS temperature, put a cooler on and leave it at that (or just use an analogue warning light), and use that input for one of the obd sensors, allowing the obd data rate to be lifted for the remainder.

Pretty sure the Racepak has a separate input for tacho, so that is another option.

OTOH, I may be way off, and the data rates may be up there where you want them.

 

I know oil pressure is transferred over to the OBDII port on the newer GM ECU's. I don't think that the OBDII port is limited to what data is fed, but the device reading it needs the PID codes to locate the data.

Racepak.com ? View topic - OBD-II question

I haven't seen any success stories about people adding PID's to the Racepak, but I'm sure it's possible.