MY Real Street 275 build
#647
#648
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Hope so.
Thanks Edgar.
You got it right!
#653
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Having issues with the valve covers and stock rocker arms.
Regarding the valve covers I'm using, the rail that retains and holds the o-ring gasket in place is wider than the LSA cylinder heads valve cover rail. So a portion of the valve cover rail is overhanging the cylinder heads valve cover rail.
When the valve is closed there is no issue with the valve covers hitting the rockers. Since the fulcrum of the rocker is not being pushed up by the push rod which would in turn push the valve down into the cylinder and "lift" the valve. The problem occurs when the valve opens and the fulcrum is pushed up by the push rod. The rocker arm contacts the valve cover rail when this occurs.
We tried to clearance one side which fixed the problem, but only temporarily. Once we fixed one side, the other side started to do it. Then we fixed that side, and the other side started to do it again! Fixed that side and it's doing it again on the other side now.
As much as I hate to do it, function comes over form in this situation and that means stock valve covers are going back on it until I figure out how to permanently fix the issue.
Regarding the valve covers I'm using, the rail that retains and holds the o-ring gasket in place is wider than the LSA cylinder heads valve cover rail. So a portion of the valve cover rail is overhanging the cylinder heads valve cover rail.
When the valve is closed there is no issue with the valve covers hitting the rockers. Since the fulcrum of the rocker is not being pushed up by the push rod which would in turn push the valve down into the cylinder and "lift" the valve. The problem occurs when the valve opens and the fulcrum is pushed up by the push rod. The rocker arm contacts the valve cover rail when this occurs.
We tried to clearance one side which fixed the problem, but only temporarily. Once we fixed one side, the other side started to do it. Then we fixed that side, and the other side started to do it again! Fixed that side and it's doing it again on the other side now.
As much as I hate to do it, function comes over form in this situation and that means stock valve covers are going back on it until I figure out how to permanently fix the issue.
#655
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Unfortunately it has nothing to do with them being taller.
The rail that retains the o-ring gasket is wider than the stock valve cover rail of the cylinder head.
This creates an overhang. When the rocker is pushed upwards by the push rod the fulcrum smacks this overhang.
The rail that retains the o-ring gasket is wider than the stock valve cover rail of the cylinder head.
This creates an overhang. When the rocker is pushed upwards by the push rod the fulcrum smacks this overhang.
#657
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Well we started making some boost finally. Waiting on FAST to call me in a little bit so they can school me on how to use this boost controller 100%.
I won't post final numbers, but what we have done so far looks extremely promising.
On waste gate the engine peaks at 7100rpm and holds peak power to 7500rpm. Haven't pulled it higher than 7500rpm yet to see how far it holds power. We're having issues with the target boost being overshot or undershot. So we've been having to abort pulls with the boost controller adding boost much earlier than where the engine actually makes peak HP.
The last pull we made had to be aborted at 6300rpm. At 6300rpm it had made 24.5-25.0psi and our target was 18psi. Because of these overshooting issues, we have the timing values extremely conservative for C16 and the air temps we're seeing from our custom built A2A.
Timing is set at 15* where this engine will easily take 20-22* at 25psi. On very similar combinations we've tuned and that I've been around, a degree of timing is easily worth 20-25hp per degree. Air temps are 92-94* at the beginning of the pull and by 6300rpm at 25psi they're only 120*. Although it's not the track which will load the engine harder and create more heat, we're ecstatic with a 25* temp gain. On a full pull to 7500-7700 we might see 35-40* gain which is fantastic for an A2A at 25psi. We do have load on the rollers of our Dyno Jet 224XLC which will simulate most of the load that the track will put on the engine, but not all of it.
On top of that the back pressure levels we're monitoring are also very good. At 6300rpm and 25psi back pressure is only 36-37psi. On a full pull we may see 40-42psi back pressure. Well under 2:1 back pressure even on high boost. Turbo seems to be very efficient so far.
Of course the numbers are what you guys want to really know and not all of the above. At 6300rpm it made 930rwhp. Had we pulled it to 7500-7700 I'm confident it would of made 975rwhp. With the timing this engine needs it will make 1050rwhp easily on 25psi. Judging by the back pressure numbers the turbo is far from done making boost and will most likely be out of steam around 28-30psi.
I won't post final numbers, but what we have done so far looks extremely promising.
On waste gate the engine peaks at 7100rpm and holds peak power to 7500rpm. Haven't pulled it higher than 7500rpm yet to see how far it holds power. We're having issues with the target boost being overshot or undershot. So we've been having to abort pulls with the boost controller adding boost much earlier than where the engine actually makes peak HP.
The last pull we made had to be aborted at 6300rpm. At 6300rpm it had made 24.5-25.0psi and our target was 18psi. Because of these overshooting issues, we have the timing values extremely conservative for C16 and the air temps we're seeing from our custom built A2A.
Timing is set at 15* where this engine will easily take 20-22* at 25psi. On very similar combinations we've tuned and that I've been around, a degree of timing is easily worth 20-25hp per degree. Air temps are 92-94* at the beginning of the pull and by 6300rpm at 25psi they're only 120*. Although it's not the track which will load the engine harder and create more heat, we're ecstatic with a 25* temp gain. On a full pull to 7500-7700 we might see 35-40* gain which is fantastic for an A2A at 25psi. We do have load on the rollers of our Dyno Jet 224XLC which will simulate most of the load that the track will put on the engine, but not all of it.
On top of that the back pressure levels we're monitoring are also very good. At 6300rpm and 25psi back pressure is only 36-37psi. On a full pull we may see 40-42psi back pressure. Well under 2:1 back pressure even on high boost. Turbo seems to be very efficient so far.
Of course the numbers are what you guys want to really know and not all of the above. At 6300rpm it made 930rwhp. Had we pulled it to 7500-7700 I'm confident it would of made 975rwhp. With the timing this engine needs it will make 1050rwhp easily on 25psi. Judging by the back pressure numbers the turbo is far from done making boost and will most likely be out of steam around 28-30psi.