ecotec swap (Page 81/98)
wftb JUL 26, 03:40 AM
So I put in the new fuel pump .The occasional stumble is gone , but it still loses power above 6100 rpm .Fuel guage still does not work , but I know why now .I have some pics I will post later to explain what is going on .I decided to try my bigger injectors , still no change .I had to change the injector constant and do a rewrite with my HP tuners so I ran a scan with my laptop to see what is happening .At anything above 6100 rpm , the tach display flashes red and the fuel gets partly cut ,kind of a soft landing that prevents any more acceleration .Somehow , the new version of HP tuners does not allow that parameter to change .And even though I tuned a 7000 Rpm fuel cutoff when I originally tuned the car , as soon as I hooked up the laptop to the car with the new version , it reverted to factory values for fuel cutoff and the speed limiter is as far as I can tell back to about 108 mph .I am emailing back and forth to find a solution but no luck so far .They were not aware of this problem .
wftb AUG 09, 11:25 PM
My tuning woes continue .The fuel cutoff is fine , there is something else wrong and I have not been able to figure it out . I have changed my tune a lot from what it was , actually downloaded one of my old tunes out of the repository and started over , but I am still having trouble with WOT above 6000 rpm .Everything else is better , high gear low rpm rollons are much stronger now and it comes out of the hole great .But above 6000 in WOT , it still loses power until I back off the throttle .I am starting to think my water meth system is not spraying .Getting about 8 degees of KR when the power drops off .I have most of thursday off to figure it out , but gone for the weekend .On the bright side , I have nothing to complain about with my new suspension . I just do not remember having so much trouble tuning before .

[This message has been edited by wftb (edited 08-21-2016).]

wftb AUG 21, 08:58 PM
I have run a lot of scans , backed off the timing at high RPM and nothing seems to help : still getting about 8 degrees of KR at WOT around 6300 RPM .I took the charge pipe off at the throttle body to check the water meth and it is spraying fine .I am beginning to suspect I am getting false knock sensing .A lot of people on ecotec.com had this problem when they went to poly motor mounts . And I now have a home made upper poly motor mount . I am going to see if I can add a bit of rubber in there to see if it changes anything .In the meantime , I am running with a 6300 RPM rev limit . The car is running very strong , the reason I like a 7000 limit is it saves a shift when I do a 0-60 run , resuting in a faster time . It probably would not affect the 1/4 time , but I have never been to a strip with this car so I would not know .
wftb SEP 07, 11:42 AM
Still playing around with the tuning .I have not had a chance to do anything with the motor mount , but I am making some progress in understanding what is happening .I have been trying to get a commanded Power Enrich AFR of 11 during high boost high rpm mode .The most it will give me is 11.5 , even though right now I have the tables set to 10 . I think I need a commanded value of 11 to get rid of the knock if it isn't false knock .There are modifier tables and I changed some of them and still no change in the PE AFR . And I managed to lower the KR but now the car does not run as strong except under WOT .So now I have to undo some of the things I changed to get back to where I was .I put the bigger HX for the air to water charge cooler back on but that had very little affect , slight decrease in IAT . I am going to add a brace to the motor mount and see how that works .

[This message has been edited by wftb (edited 09-07-2016).]

wftb SEP 07, 10:38 PM
Made the brace today , no time to try it out though .Paint a little rough , just wanted it not to rust for now .
wftb SEP 12, 01:54 PM
The brace did not seem to make an improvement in the knock problem .It does make it less prone to movement so I still consider it an improvement . My lack of knowledge of tuning is a problem , but I am doing a lot of research and making slow progress .I found out that on my ECM that when any knock is detected , it immediately changes to the Low Octane spark tables .This caused power to fall right off at about 6100 RPM . I had left all the LO tables alone , thinking they were irrelevant . So I rewrote those tables in the high RPM areas and that made a decent improvement .Also the VE offset seems to be critical .Stock seemed to be 20% , I have tried 40 % and then back to 20% and now I am running 45% .Higher values make the car smoother and keep LTFT and STFT in the green range .I noticed on one tune , the VE offset was 60 % . I may try that figure and if it does not help , go back down to 45 % .
wftb OCT 03, 11:08 PM
I have done a lot of tuning and I have come to the conclusion that the power drop off at 6300 is caused by my new 2" exhaust setup .The give away was I did a scan with the PE shut off and got the same results as with it on .I started looking at the KR and realized it really was not that bad compared to older scans. So I am pretty sure that my 2" piping is at least 1/4" to small .The 20G turbo is getting strangled by the low flow of the 2" system .I put the smaller piping in to promote low end response ( and it did ) but I did not realize how much it would affect the higher revs .I thought the blow off valve was leaking but a new one did nothing .Bumping up the boost did nothing as well . So , I am going to make a new 2.5 " exhaust .Should not cost much , I can salvage most of it from my old exhaust and I have a ton of extra pipe bends .I will need a new flex pipe , I don't have another short 2.5" laying around .
wftb OCT 12, 01:25 PM
Yesterday I looked around the garage and came up with enough bits and pieces to cobble together a new 2.5" exhaust system .The only thing I had to buy was a short flex pipe , 22.00 from Spikes Auto Parts and he had it in stock .I had the day off so I started at 8:30 am and other than lunch I worked straight through and had it done by 7:00 pm .Not a thing of beauty , I had to weld 3 short straight pipes together to make the cat back pipe but it works and only one leak in a spot that does not matter .And it has solved my lack of power above 6300 rpm - it now revs and pulls really strong right up to the 7000 rpm redline I have it set at .The welds are pretty rough , I kept blowing holes in the thin stainless pipe I used .


I did not get the angle on the tail pipe right , something I will fix with a vband coupler when I can pick one up:

[This message has been edited by wftb (edited 10-12-2016).]

wftb OCT 13, 02:38 PM
New 4.12 sq " area dual piston willwood calipers .Hoping the reduction in area from the old single 2.5" diameter piston (4.9 sq ") will end my right front lockup problems .Other than stock ,every brake setup I have used has had right front lockup .Still stops straight and in short distances , but the smoke show coming from the right front tire is beyond annoying .
here are a few pics of the new calipers , these are Willwood #120-11872-RD



If these don't work , I am going to gut the proportion valve and install a bias valve going to the rear brakes .I am going to have a collection of Willwoods to sell in the mall soon .Now that I have solved my engine tuning problems , I can concentrate on brakes and chassis tuning .
wftb OCT 16, 04:06 PM
These calipers have made a big improvement . Stopping much better .But now both fronts lock up when you really jump on the brakes .Not locking up completely , a lot less smoke and good that both fronts are now doing the same thing . I am looking in to new stickier tires in slightly bigger sizes .Going to 215/55/r16 in the front and 255/50/16 in the back .This will maintain the width spread of 40 that I have now that works really well .I would like to get another set of Kumhos but they no longer make the same tire as I have now in the sizes I need .So far , the BFG G-Force Sport Comp- 2 seem to be the only Hi-Po summer tire that will do the job in my sizes .And it has great reviews . Most MFR's have very little in a 16" wheel size in a summer only tire .