qbnkiller
Conflaguration Specialist
Last year I was able to successfully run my combination to a best pass of 10.75 @ 127mph at 24# of boost. Towards the end of the season, I started to turn the boost up, but had some small gremlins pop up.
Over the winter, I decided to tear the engine down, have a look inside, and make changes accordingly..As a recap, this was a thumbnail sketch of my engine combo:
Stock block 0.030" overbore, 4-bolt mains, strap front and rear, short-fill
stock crank, cryo, turned down 0.030"/0.020"
Eagle rods, MAHLE pistons (8.5:1), ARP main studs
L35 heads, custom COMP CAMS grind, ARP head bolts, Cometics
Edelbrock #2111 intake, elbow, 80mm TB, 85#/hr injectors
Bullseye Power CompR62 turbo, external 38mm wastegate, custom W2A IC
BigStuff3 ECM tuned by me
When I tore the engine down, I was pleasantly surprised to find no drama...everything looked great! I learned a bunch about what my engine liked and didn't like, and I made a few small changes to the combination for this year - namely:
120#/hr injectors
Custom camshaft
Bullseye Power CompR66 turbo
torque converter change
Progress was slow but methodical. This was due to my heavy travel schedule for work. Last week, I finally had finished the engine and was ready to dyno test it before I stabbed it in the truck.
Since I did make some changes to the configuration, I started with low-boost pulls to get a baseline. I set the boost controller to 16# and made a few pulls. 553HP/647TQ. Torque was above 600 ft. lbs. from 3700 to 5100rpm. HP was above 500HP from 4000 to 6000rpm. I did numerous plug reads to gauge where the engine wanted the AFR's to be at. I can tell you that what it wanted and what I thought it wanted were almost a full point away from each other!
Next up was turn the boost up to 24#. I made a few quick adjustments to the boost controller and let her eat. The pull was clean, but AFR's were very very fat. Results were 671/743TQ. TQ was 729 by 3700rpm and stayed above 700 to 4900rpm. HP was above 600 from 4300 to 5900rpm. Shut the engine down, made a few adjustments to the fuel map, and started it again. It was a harder start than normal, but eventually fired back up and we made another pull. The numbers were identical and AFR's did not move at all. The engine idled there for a couple minuted before I shut it down. I reviewed the log file, made more fueling changes, and shut it down for lunch.
When I got back, I tried to start the engine and it would not turn over. I pulled #4 plug out and a stream of water shot out and soaked me - DAMMIT! I popped a gasket! Disillusioned, I tore the top-end off the engine right there ont he dyno. Looking at the head gaskets, I saw nothing wrong. Looked at the two surfaces and didnt see anything jump out. I finished pulling the engine off the dyno cart and called it a day.
The following morning, I tore my heads down completely and found #4 intake runner had a hole the size of a pencil head which was leaking coolant into the engine. Apparently the metal in that area was a bit thin, and my years of abuse on these heads finally pushed through it. I then took to more carefully inspecting all the runners and I found another suspect area that - if it wasn't already leaking a very slight amount, it soon would have.
I had to make a decision as to which way to go now. I went to the junkyard and picked up a set of 99 VORTEC heads - I am going to the dark side! In the coming weeks (again - busy travel schedule) I will get all my old parts onto these newer VORTECS and retest. I will now have hard data on what differences L35's to VORTEC heads can do. The VORTECS will be unported - just cut for 2.02/1.60 valves and my springs.
All in all, I am fairly pleased in the progress made so far. I can tell you that the power it made at 24# is still conservative in many respects - the tune is still way too rich for max power. This turbo, in my opinion, is sized perfectly for our application. In my testing, I had 24# of boost by 3300rpm. The power curve when plotted out is almost ruler-flat. It will be interesting to see how it does when I turn it up a little more, and when I add an intercooler (yes these numbers were WITHOUT ANY INTERCOOLER WHATSOEVER).
Over the winter, I decided to tear the engine down, have a look inside, and make changes accordingly..As a recap, this was a thumbnail sketch of my engine combo:
Stock block 0.030" overbore, 4-bolt mains, strap front and rear, short-fill
stock crank, cryo, turned down 0.030"/0.020"
Eagle rods, MAHLE pistons (8.5:1), ARP main studs
L35 heads, custom COMP CAMS grind, ARP head bolts, Cometics
Edelbrock #2111 intake, elbow, 80mm TB, 85#/hr injectors
Bullseye Power CompR62 turbo, external 38mm wastegate, custom W2A IC
BigStuff3 ECM tuned by me
When I tore the engine down, I was pleasantly surprised to find no drama...everything looked great! I learned a bunch about what my engine liked and didn't like, and I made a few small changes to the combination for this year - namely:
120#/hr injectors
Custom camshaft
Bullseye Power CompR66 turbo
torque converter change
Progress was slow but methodical. This was due to my heavy travel schedule for work. Last week, I finally had finished the engine and was ready to dyno test it before I stabbed it in the truck.
Since I did make some changes to the configuration, I started with low-boost pulls to get a baseline. I set the boost controller to 16# and made a few pulls. 553HP/647TQ. Torque was above 600 ft. lbs. from 3700 to 5100rpm. HP was above 500HP from 4000 to 6000rpm. I did numerous plug reads to gauge where the engine wanted the AFR's to be at. I can tell you that what it wanted and what I thought it wanted were almost a full point away from each other!
Next up was turn the boost up to 24#. I made a few quick adjustments to the boost controller and let her eat. The pull was clean, but AFR's were very very fat. Results were 671/743TQ. TQ was 729 by 3700rpm and stayed above 700 to 4900rpm. HP was above 600 from 4300 to 5900rpm. Shut the engine down, made a few adjustments to the fuel map, and started it again. It was a harder start than normal, but eventually fired back up and we made another pull. The numbers were identical and AFR's did not move at all. The engine idled there for a couple minuted before I shut it down. I reviewed the log file, made more fueling changes, and shut it down for lunch.
When I got back, I tried to start the engine and it would not turn over. I pulled #4 plug out and a stream of water shot out and soaked me - DAMMIT! I popped a gasket! Disillusioned, I tore the top-end off the engine right there ont he dyno. Looking at the head gaskets, I saw nothing wrong. Looked at the two surfaces and didnt see anything jump out. I finished pulling the engine off the dyno cart and called it a day.
The following morning, I tore my heads down completely and found #4 intake runner had a hole the size of a pencil head which was leaking coolant into the engine. Apparently the metal in that area was a bit thin, and my years of abuse on these heads finally pushed through it. I then took to more carefully inspecting all the runners and I found another suspect area that - if it wasn't already leaking a very slight amount, it soon would have.
I had to make a decision as to which way to go now. I went to the junkyard and picked up a set of 99 VORTEC heads - I am going to the dark side! In the coming weeks (again - busy travel schedule) I will get all my old parts onto these newer VORTECS and retest. I will now have hard data on what differences L35's to VORTEC heads can do. The VORTECS will be unported - just cut for 2.02/1.60 valves and my springs.
All in all, I am fairly pleased in the progress made so far. I can tell you that the power it made at 24# is still conservative in many respects - the tune is still way too rich for max power. This turbo, in my opinion, is sized perfectly for our application. In my testing, I had 24# of boost by 3300rpm. The power curve when plotted out is almost ruler-flat. It will be interesting to see how it does when I turn it up a little more, and when I add an intercooler (yes these numbers were WITHOUT ANY INTERCOOLER WHATSOEVER).
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