C16

[Turboflash]

I'm looking for experiences/comments/knowledge about occasionally using C16 to speed run/drag race 998s. I've searched TY and found some info but looking for more. I occasionally like to speed run/drag race (run-what-you-brung, LOL).

I currently have PEFI Stage 4 (4-bar 330HP pump gas tune) with 3" small-body Sandale, PEFI header, PEFI big fuel pump, tall gears, 240 1.575" Megabites, 137" track). In order to use the PEFI waste gate lock, I pump out all pump gas and put in straight fresh C16. Waste gate locked to .030". I control boost on this tune to about 24-26 psi. The C16 allows this boost without deto and AFR is safe at about 12.0 for 1/4 mile pulls.
Questions:
A. Are there "unhealthy" consequences using C16 as far as fuel system is concerned (fuel pump, injectors, FPR)? Unhealthy means serious corrosion, degradation effects? Can it ruin fuel system components? I know it's highly leaded and eventually does ruin the O2 sensor. I just replace sensor when needed.
B. How long can C16 be left in sled before any negative things start to happen?

Thanks in advance for any comments.

 

[sideshowBob]

I have no 998 experience with C16 but your sled must be a trail rocket with that kind of boost. Do you not run into part throttle overboost issues with the locked waste gate?

 

[NYTurbo]

I’ve left it the tank for a month or so . Never an issue. Oxygenated fuels I wouldn’t leave in there too long like import or q16 their supposed to be corrosive , yet I know guys that don’t worry about those either

 

[Turboflash]

I have no 998 experience with C16 but your sled must be a trail rocket with that kind of boost. Do you not run into part throttle overboost issues with the locked waste gate?

Not so far but I don't run locked waste gate on trail, only to race. Trail boost is about 19-20 w header.
Locked waste gate (.030) @ 26 psi takes 92 grams per arm to run 8900 w ADAPT primary, Team Boss secondary. Calculates to about 375+ HP.
If we ever get snow, I'll do some runs w my new Dragy and post.

 

[Fleecer]

I'm told a lot of use is corrosive to the valves and causes pitting, which in turn prevents a good seal between the head and valve. This requires pulling the head off, lapping valves and re-assembly.......minor job for a master technician like yourself.

 

[Trailleader]

About a week but you can get away with longer.
When you’re done just clean it out for peace of mind. Also hard on sensors
Run q16 as it will make more power and start in cold weather. You use more fuel though and the stage 4 pefi uses stock injector. Probably why it supposedly makes 325 on pump and 337 on race.
You’re actually locking the gate manually and not running the turbo smart gate?

 

[NYTurbo]

Q16 you’ll need a way to add extra fuel to your tune if it’s designed for c16

 

[sideshowBob]

Q16 you’ll need a way to add extra fuel to your tune if it’s designed for c16

Closed loop with proper fuel pressure should do it but I don't think PEFI offers closed loop?

 

[NYTurbo]

Closed loop may but the stock injectors could be the deciding factor. May have tp raise pressure as welll

 

[Turboflash]

I'm told a lot of use is corrosive to the valves and causes pitting, which in turn prevents a good seal between the head and valve. This requires pulling the head off, lapping valves and re-assembly.......minor job for a master technician like yourself.

Oh yeah, tons of fun! Lol

 

[Turboflash]

Closed loop may but the stock injectors could be the deciding factor. May have tp raise pressure as welll

Stage 4 PEFI is 4-bar tune that requires 58 psi (key on engine not running) w stock injectors. I have TD adjustable FPR and AEM AFR gage on handlebars so I can watch AFR. PEFI Stage 4 rated at 325 "pump", 337 "Race gas" with their restrictive 2.5" "performance trail" muffler. I'm running 3" small-body straight-through Sandale. On standard Stage 4 map, I need to run 61 lbs if FP to cover the 3" Sandale vs PEFI 2.5". AFR right at 11.8-12 depending on outside temp.
Stage 4 has a "Race Map" that I believe is what prevents overbooat at 24-26 psi boost on C16. IDK. I just know I don't get shut down due to overboost.

Closed loop may but the stock injectors could be the deciding factor. May have tp raise pressure as welll

I run about 61 psi key on engine not running. PEFI Stage 4 kit comes w 4-bar FPR (58) psi.

 

[Turboflash]

About a week but you can get away with longer.
When you’re done just clean it out for peace of mind. Also hard on sensors
Run q16 as it will make more power and start in cold weather. You use more fuel though and the stage 4 pefi uses stock injector. Probably why it supposedly makes 325 on pump and 337 on race.
You’re actually locking the gate manually and not running the turbo smart gate?

Thanks. I was concerned about leaving it in for a few days.

 

[NYTurbo]

So your going to have to run more fuel pressure, your almost at your limit IMHO at 61 pounds plus a pound per boost.

Only one way to find out as u can monitor AFRS

 

[Fleecer]

I think a 50/50 mix of 93 and c16, which comes out to 104.5 octane should be plenty safe to run that setup?

 

[Trailleader]

Thanks. I was concerned about leaving it in for a few days.

The c isn’t like the q in the motor for the corrosion but it will loose octane sitting. No reason to leave it in for very long period.
I have used c but really only use oxygenated fuel for the free hp. It takes more fuel and you’ll need to monitor afr for sure.
Like I said above it will fire much better in cold weather too.