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Ellis V Buth · 10-24-2023, 01:05 PM

This post will catch us up to before the Fall Classic.

After Columbus, we tested multiple things and tried many different theories. We procured a set of NOS 7x19.5 slicks that are a bit softer than the road race/circle track tires we had. We read Billy Nees build thread on the Cavalier and tried some of the tricks he tried (flopping the cams specifically) but our results for all of these tests yielded a series of runs between 16.53 and 16.51 in the morning air at each track (Indy, BG, testing at various bracket events and Wild Wednesday). A few of our tests (smaller injectors to try and help the 10:1 AFR with the stock tune while waiting on the new computer to arrive) resulted in significantly slower runs. We even tried tricking the car into thinking it was running at a different temperature to try and get the AFR back in line and resulted in significantly slower runs!

We were able to procure an 05 Cavalier computer and wiring harness which will allow us to tune the car. Getting away from the stock computer and moving to a tuneable ECM ended up being the proper solution. We found a company in Michigan that had all the equipment and it came pre-loaded with their "drag race tune" and we took it to the 1/8 mile track in Terre Haute. The AFR and timing curve are specifically what interests us initially...AFR being pegged at 10:1 and timing being locked out at 20 degrees has to be our biggest limiting factors. We are also interested in messing with the shift points and trying to lower the line pressures (another idea we got from Billy). The test and tune at Terre Haute yields our quickest 1/8 mile passes to date (10.40 compared to prior 10.60s) so we are now convinced that we are under the index on the 1/4 mile.

St. Louis double divisional is the official debut of the car with the tuneable ECM and it does not disappoint. Based on our 1/8 mile data and some tune changes we have queued up, we believe the car should be around a 15.99 if everything carries down track like we think it should. Our initial run with the baseline tune ends up with a 16.21 at 84 MPH. A full 3 tenth improvement from the prior 16.51 best! We are now under the index. We load up the tune changes that we believe will pick the car up another couple tenths and we wait for 2nd qualifier to try and get in the show. The weather, however, had other ideas and we ended up outside the show and with an untested tune for race 2.

Luckily, several cars left between races and we only have to out-qualify a couple of cars (which we didn't know when qualifying started). We leave the new tune in the car and we put the "class oil" (FL0) in the car to ensure that we should be far enough under to beat a few cars. The wind has changed to a head wind which slows the Ranger down 8 hundredths on this run, but the Cobalt goes out and runs 16.02!!! The changes in tune and the "class oil" combined picked us up almost another 2 tenths. We are now .475 under the index in the same weekend we made our first under the index pass at all.

The ECM was $900, tires were $300 plus shipping, other miscellaneous parts and pieces and tax from the rest of the year all add up to a total of $1,800 spent to get the car from completely street to around .5 under. Obviously, if we could have gotten the ECM sooner we could have saved some of the smaller tests and saved a little money along the way. I'd estimate the extra savings would have been in the $100-200 range but we wanted to get the car under the index however we could while we were waiting on the ECM.

There is still 1 more race on our schedule after St. Louis and plenty more to update on the build over the winter.

10-24-2023, 01:05 PM	#16
Ellis V Buth Junior Member Join Date: Sep 2015 Posts: 83 Likes: 44 Liked 291 Times in 56 Posts	Re: Slobalt This post will catch us up to before the Fall Classic. After Columbus, we tested multiple things and tried many different theories. We procured a set of NOS 7x19.5 slicks that are a bit softer than the road race/circle track tires we had. We read Billy Nees build thread on the Cavalier and tried some of the tricks he tried (flopping the cams specifically) but our results for all of these tests yielded a series of runs between 16.53 and 16.51 in the morning air at each track (Indy, BG, testing at various bracket events and Wild Wednesday). A few of our tests (smaller injectors to try and help the 10:1 AFR with the stock tune while waiting on the new computer to arrive) resulted in significantly slower runs. We even tried tricking the car into thinking it was running at a different temperature to try and get the AFR back in line and resulted in significantly slower runs! We were able to procure an 05 Cavalier computer and wiring harness which will allow us to tune the car. Getting away from the stock computer and moving to a tuneable ECM ended up being the proper solution. We found a company in Michigan that had all the equipment and it came pre-loaded with their "drag race tune" and we took it to the 1/8 mile track in Terre Haute. The AFR and timing curve are specifically what interests us initially...AFR being pegged at 10:1 and timing being locked out at 20 degrees has to be our biggest limiting factors. We are also interested in messing with the shift points and trying to lower the line pressures (another idea we got from Billy). The test and tune at Terre Haute yields our quickest 1/8 mile passes to date (10.40 compared to prior 10.60s) so we are now convinced that we are under the index on the 1/4 mile. St. Louis double divisional is the official debut of the car with the tuneable ECM and it does not disappoint. Based on our 1/8 mile data and some tune changes we have queued up, we believe the car should be around a 15.99 if everything carries down track like we think it should. Our initial run with the baseline tune ends up with a 16.21 at 84 MPH. A full 3 tenth improvement from the prior 16.51 best! We are now under the index. We load up the tune changes that we believe will pick the car up another couple tenths and we wait for 2nd qualifier to try and get in the show. The weather, however, had other ideas and we ended up outside the show and with an untested tune for race 2. Luckily, several cars left between races and we only have to out-qualify a couple of cars (which we didn't know when qualifying started). We leave the new tune in the car and we put the "class oil" (FL0) in the car to ensure that we should be far enough under to beat a few cars. The wind has changed to a head wind which slows the Ranger down 8 hundredths on this run, but the Cobalt goes out and runs 16.02!!! The changes in tune and the "class oil" combined picked us up almost another 2 tenths. We are now .475 under the index in the same weekend we made our first under the index pass at all. The ECM was $900, tires were $300 plus shipping, other miscellaneous parts and pieces and tax from the rest of the year all add up to a total of $1,800 spent to get the car from completely street to around .5 under. Obviously, if we could have gotten the ECM sooner we could have saved some of the smaller tests and saved a little money along the way. I'd estimate the extra savings would have been in the $100-200 range but we wanted to get the car under the index however we could while we were waiting on the ECM. There is still 1 more race on our schedule after St. Louis and plenty more to update on the build over the winter.