'91 #473 Tuning - Page 12 - ZR-1 Net Registry Forums

Billy Mild · 02-04-2017

Are you burning new chips or using an APU1 unit?

jss06c6 · 02-04-2017

Burning chips. Still fine tuning spark and fuel (VE). I've dropped the point where the secondaries open to bring the power in sooner. Nice rush without lots of throttle required. Been a while since I've updated everyone. I'll try to get a good summary posted later today!

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Billy Mild · 02-05-2017

Were there any issues you had with Haibecks tune, or are you just wanting to squeeze every last HP out of the tune?

jss06c6 · 02-05-2017

Most of my time is spent in getting the Volumetric Efficiency dialed in. The engine was running very lean, but at WOT, it was a bit rich. Marc can't tune the VE remote since each engine has its own signature. He can do it if he has the car, but his mail order tunes are based upon his intimate knowledge of the LT-5 and he gets most of the way there while keeping the engineering safe. I've made substantial changes to the VE tables which dials in the fuel when not in Power Enrichment mode (WOT). The engine will have some additional HP as a result, but not a huge gain. It simply will run at peak efficiency. I have made some changes to the PE curve to bring down the fuel (think of it as a sustained pump shot in a carbureted set up). Using wideband O2 sensor, my AFR is now about 12.5. I will bring it down to 12.8-13.1, which matches Marc's ideal.

In summary, Marc's tune is exceptional for not having access to my car. I love to tune, so my time is spent refining his work to match my car.

I'll head back to the dyno later this spring to see where it sits, but I'm not trying to get HP as much as I am focused on optimizing the tune to get the engine operating at its best.

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XfireZ51 · 02-05-2017

The curse and blessing of doing your own tuning is that you customize the performance and responsiveness of the car to your tastes.
On the other hand, you never stop which is why I usually have the Ostrich running the car.
Sometimes I take a break. Recently put in 4.10s so I want to check what if anything needs to be modified because of that.

jss06c6 · 02-05-2017

Ostrich is a good next step. I'll be pulling the plenum and doing some mild porting, so will start all over again with fuel and spark! Insanity, but fun!!!

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XfireZ51 · 02-05-2017

Quote:

Originally Posted by jss06c6

Ostrich is a good next step. I'll be pulling the plenum and doing some mild porting, so will start all over again with fuel and spark! Insanity, but fun!!!

Sent from my XT1585 using ZR-1 Net Registry mobile app

Yeah, I just pretty much leave it in there. I carry a spare prom just in case, but I've had Ostrich running the motor for months at a time. Need to be careful it doesn't get wet so I put it in a ziplock sometimes.

jss06c6 · 02-05-2017

Quote:

Originally Posted by XfireZ51

Yeah, I just pretty much leave it in there. I carry a spare prom just in case, but I've had Ostrich running the motor for months at a time. Need to be careful it doesn't get wet so I put it in a ziplock sometimes.

Dominic,

Also thinking about locating the APU in the center console and building a custom cable to the ECM so I can leave it in place out of the weather for extended periods of time...

Steve

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jss06c6 · 03-06-2017

Gents,

Been a while and a lot of chips burned in the last 60 days. I got the VE tables looking good below 3500 RPM, but couldn't get the guts to try higher revs without the insurance of PE in place. I left my PE% change to Fuel/Air Ratio vs. RPM where Marc H. put it. Logged enough VE data with secondaries commanded open to get a decent look at the upper VE table (port open).

Had a number of 100 kPa zones at or exceeding VE of 100%! With the help of my Wideband and the ability to log this data, I could see three RPM zones where I was running rich at WOT. 2,000-3,000 was at AFR of 12.8 (target), 3,000-4,000 was at AFR of 12.3, 4,000-5,225 was at AFR of 12.1, 5,250-5,825 was at AFR of 12.5.

All power bands were rich, as suspected. I rolled timing down a bit as I was seeing too much knock (23-24 degrees at WOT and 3,000 to 6,500 rpm).

Tried to fine tune the PE curve... No luck. The algorithm overrode my entries and forced some wierd numbers. I left them alone and made the changes to the VE table to lean it out. Results put me spot on the target AFR of 12.8 at WOT across the board. #473 pulls well into the 7,000 band! I'll head back to the dyno to check the results of my tuning efforts. Suspect I found some of the 16 HP Marc suspected was there for the taking.. Will see! Meantime here's the dyno pass before the tuning work.. 345 rwhp, 349 rwtq..

https://youtu.be/lWVm_iVYpII

Sent from my XT1585 using ZR-1 Net Registry mobile app

02-04-2017	#111
Billy Mild Join Date: Aug 2014 Location: Kansas City, MO Posts: 838	Re: '91 #473 Tuning Are you burning new chips or using an APU1 unit? __________________ Looking for a ZR-1 1985 Yamaha RZ350-NOT STOCK 1971 Yamaha AT1-Middle of a restoration

02-04-2017	#112
jss06c6 Join Date: Aug 2015 Location: Magnolia, Texas Posts: 884	Re: '91 #473 Tuning Burning chips. Still fine tuning spark and fuel (VE). I've dropped the point where the secondaries open to bring the power in sooner. Nice rush without lots of throttle required. Been a while since I've updated everyone. I'll try to get a good summary posted later today! Sent from my XT1585 using ZR-1 Net Registry mobile app

02-05-2017	#113
Billy Mild Join Date: Aug 2014 Location: Kansas City, MO Posts: 838	Re: '91 #473 Tuning Were there any issues you had with Haibecks tune, or are you just wanting to squeeze every last HP out of the tune? __________________ Looking for a ZR-1 1985 Yamaha RZ350-NOT STOCK 1971 Yamaha AT1-Middle of a restoration

02-05-2017	#114
jss06c6 Join Date: Aug 2015 Location: Magnolia, Texas Posts: 884	Re: '91 #473 Tuning Most of my time is spent in getting the Volumetric Efficiency dialed in. The engine was running very lean, but at WOT, it was a bit rich. Marc can't tune the VE remote since each engine has its own signature. He can do it if he has the car, but his mail order tunes are based upon his intimate knowledge of the LT-5 and he gets most of the way there while keeping the engineering safe. I've made substantial changes to the VE tables which dials in the fuel when not in Power Enrichment mode (WOT). The engine will have some additional HP as a result, but not a huge gain. It simply will run at peak efficiency. I have made some changes to the PE curve to bring down the fuel (think of it as a sustained pump shot in a carbureted set up). Using wideband O2 sensor, my AFR is now about 12.5. I will bring it down to 12.8-13.1, which matches Marc's ideal. In summary, Marc's tune is exceptional for not having access to my car. I love to tune, so my time is spent refining his work to match my car. I'll head back to the dyno later this spring to see where it sits, but I'm not trying to get HP as much as I am focused on optimizing the tune to get the engine operating at its best. Sent from my XT1585 using ZR-1 Net Registry mobile app

02-05-2017	#115
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,669	Re: '91 #473 Tuning The curse and blessing of doing your own tuning is that you customize the performance and responsiveness of the car to your tastes. On the other hand, you never stop which is why I usually have the Ostrich running the car. Sometimes I take a break. Recently put in 4.10s so I want to check what if anything needs to be modified because of that. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX Last edited by XfireZ51; 02-05-2017 at 03:12 PM.

02-05-2017	#116
jss06c6 Join Date: Aug 2015 Location: Magnolia, Texas Posts: 884	Re: '91 #473 Tuning Ostrich is a good next step. I'll be pulling the plenum and doing some mild porting, so will start all over again with fuel and spark! Insanity, but fun!!! Sent from my XT1585 using ZR-1 Net Registry mobile app

03-06-2017	#119
jss06c6 Join Date: Aug 2015 Location: Magnolia, Texas Posts: 884	Re: '91 #473 Tuning Gents, Been a while and a lot of chips burned in the last 60 days. I got the VE tables looking good below 3500 RPM, but couldn't get the guts to try higher revs without the insurance of PE in place. I left my PE% change to Fuel/Air Ratio vs. RPM where Marc H. put it. Logged enough VE data with secondaries commanded open to get a decent look at the upper VE table (port open). Had a number of 100 kPa zones at or exceeding VE of 100%! With the help of my Wideband and the ability to log this data, I could see three RPM zones where I was running rich at WOT. 2,000-3,000 was at AFR of 12.8 (target), 3,000-4,000 was at AFR of 12.3, 4,000-5,225 was at AFR of 12.1, 5,250-5,825 was at AFR of 12.5. All power bands were rich, as suspected. I rolled timing down a bit as I was seeing too much knock (23-24 degrees at WOT and 3,000 to 6,500 rpm). Tried to fine tune the PE curve... No luck. The algorithm overrode my entries and forced some wierd numbers. I left them alone and made the changes to the VE table to lean it out. Results put me spot on the target AFR of 12.8 at WOT across the board. #473 pulls well into the 7,000 band! I'll head back to the dyno to check the results of my tuning efforts. Suspect I found some of the 16 HP Marc suspected was there for the taking.. Will see! Meantime here's the dyno pass before the tuning work.. 345 rwhp, 349 rwtq.. https://youtu.be/lWVm_iVYpII Sent from my XT1585 using ZR-1 Net Registry mobile app Last edited by jss06c6; 03-06-2017 at 10:18 PM.