Here is the first dyno numbers- the baseline was Texas Speed Longtubes installed, no cats, stock tune. After some adjustments here is the preliminary after. There is more work to be done, Ported Throttle Body and E85 results. So this is the beginning. I will be out of the Country for a week, more when I return.

 

do you have before and after air fuel ratios and spark timing values, by chance?

 

just stopped by and saw they were working on it, took a quick photo of the screen. Will have more when it is ready, should have AFR on it.

 

in.

 

Numbers seem low...what afr and timing?

 

 

Seems spot on for just headers and tune

 

Higgs we think alike lol

 

How many C7's has Powerfab tuned (if you know this) by chance? Tuner's name? Any particular reason you went with PF? Any info greatly appreciated.

PF has been around for a long time, guy "meatball" used to have a nasty TT G35 widebody years and years ago. I know they were big on the GTR's back then also.

 

I went with Power fab based on a long term basis. Jeff is the tuner. My other tuner is Matt Sorian in Florida (FSP) and now that I live in Houston, I was looking for a reputable shop that has had very little to no turnover. Several of my friends have been customers of Power Fab. All have had nothing but good to say. When I was "interviewing" tuners, they offered the best advice and told me how they tune for E85. The other tuners in the area, with two exceptions, had not done any. The other tuner in the area will be moving soon, so I did not feel this was the best choice. Once tuned by Powerfab you become "family". any tweaks or updates if needed are free and if you need time on the dyno, you are only charged dyno time. They had 3 other C7's in the shop for various mods, nitrous, e85, ect. They build all their turbo systems in house, if I ever wanted to do that as well. LS swaps there are abundant too, from BRZs, to mustangs and Datsuns and Nissans. If it has a motor, they can swap a LS in. with no turnover and an excellent reputation in Houston with the knowledge to back it up sold me on them. There are other good shops in Houston, HP, LMR, Serious HP to name a few and I am friends with all of them. I support the good ones and they support me. Each shop has specialties to utilize.

 

This was just Longtubes, Ported throttle body, haltech intake and E85 still be be tuned. Looking at gains with each mod. Ported Throttle body netted 2 hp, about right, was not really expecting much , if any, gain with that. plus I am in Cancun right now, so limited access to dyno results.

 

I appreciate the info man, as I'm in Htown also. The time will come when I need to choose a tuner...

Yeah, PF has always had a good reputation for the 7-8 years I've known of them. A bit on the pricey side, but consensus has always been they give you quality work for the money, which is ultimately what I am looking for. Although I know their past reputation, it's been a while since I've heard anything about them and I didn't know how many C7's they have had there hands on, so thanks for that from an unbiased source.

I'll keep up with your build and tuning to see how it goes.

 

ok, stock intake, E85 and TSP Longtubes - no cats- 450 RWHP. Intake has not made it in yet so will have to get results on that later. Actual Dyno chart when I get back in the country. This is on a DynoJet Dyno in Houston heat and humidity.

 

That looks much better.

 

That looks a little better

 

Once you get the E85 activated in your tune and make all the appropriate changes in the tune--you should see even more HP---
The stock E85 Tune adds another 3-5* of timing from 3400 on up--
I experienced NO KR or pinging- and my timing jumped up to 26-27* at WOT from the stock peak timing of only 19-23*
From idle to about 1800 the E85 STOCK tune evens adds more timing starting at 17* at idle to about 7* at 1800 at mid throttle
My car stumbled somewhat in off idle to 1800 before activating the tune--

 

What sensor is used for the car to be E85 aware? I've always wondered if flex-fuel cars sense E10 and end up adjusting stoich to something like 14.50; thus making the tune run slightly richer than if it were eth-unaware. Aren't there "% alcohol" based modifiers for just about everything (that could thus be impacted by it's presence).. including advance adders dependent on % alcohol.. I haven't seen a C7 tune yet.. but as with most new tunes.. it's very hard to visualize; a 7 dimensional sort of thing.. nothing is linear. Which isn't a bad thing, but it can be if approached with a linear mindset.. if I do X then Y will happen often doesn't work out so well.

But I digress. What sensor.

 

This should help: https://www.corvetteforum.com/forums...r-install.html

 

Awesome, thanks for answering both of my questions! Interesting to see that stoich is set to 14.1084 across the board. What kicks the car over into 'alcohol' mode as per the AFR correction tables.. If the car is deemed to be running alcohol, in power enrich mode.. it pulls a bit of timing relative to gas mode.. but only because there is a separate table that adds timing in flex fuel mode at high cyl airmass. In HPT, this modifier table is under "misc" and has it's own multiplier table based on fuel comp; thus E50 WOT would actually run less timing than garden variety E10. It would add half of what the "Flex Fuel Spark" adds to the main spark table and then pull it back out based on the alcohol AFR correction table. In fact, in some places.. the Flex Fuel Spark adder table adds less than AFR alcohol correction takes out.. So there are some places in which E85 would run less timing than standard E10. There must be yet another mult/mod table I'm missing!

This tune exceeded my already high expectations for complexity and layers of multipliers and adders. Yikes.

 

Light Loads timing needs to be less than regular gasoline, only at higher loads do you need more timing.

Quote from Greg Banish
"All else being equal, the laminar flame speed of ethanol combustion is faster than that of gasoline. Faster flame = less spark advance required to deliver peak pressure at the right point of the engine cycle. Ethanol has a faster burn rate than gasoline. It just has a much higher AKI (knock index) so you are rarely limited by knock at WOT which allows you to run more timing at high load. At high load, we're typically limited by gasoline's relatively low knock threshold. Since the knock threshold of alcohols are higher, you can run closer to MBT timing without getting into knock at high load."