Borg Warner EFR 7670 T4 1.05AR - Detailed Pics
Dec 4, 2011, 05:32 PM
#61
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Location: New Holland, Pa
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Very anxious for results.
Previous results showing torque and boost drop is a bit of a let down.
Of there is one set up that should hold boost and torque all the way to 8500+ its yours rt
Should be very informative
Previous results showing torque and boost drop is a bit of a let down.
Of there is one set up that should hold boost and torque all the way to 8500+ its yours rt
Should be very informative
Dec 13, 2011, 07:59 PM
#64
I'm looking into making it out of sch10 Titanium. I think I've found a source for the weld els. Now I'll just need to pony up the money to buy the Ti-plate to have it machined.
I'll need a nc'd head flange, T4 divided flange, and 2 TiAL MVS flanges. I'll be modeling them in cad and then paying some of our machine shop guys in cases of beer for NC time on the Mazak and our NC lathe.
I got my tutorial book for FEA using V5R19... I can't wait!
I'll need a nc'd head flange, T4 divided flange, and 2 TiAL MVS flanges. I'll be modeling them in cad and then paying some of our machine shop guys in cases of beer for NC time on the Mazak and our NC lathe.
I got my tutorial book for FEA using V5R19... I can't wait!
Dec 11, 2014, 05:18 AM
#69
Evolved Member
Dec 11, 2014, 05:26 AM
#70
S3's, 8800rpm, 7670 with itty bitty turbine wheel @ 320kpa (tons of backpressure), combined with a spark cut rev limiter.
I believe the ignition in the exhaust manifold during the spark cut rev limiter generated enough back pressure to push the exhaust valves open and strike the intake valves... causing 1 of them to bend. I can see witness marks on the face of the exhuast valves from where they have hit the edge of each intake valve.
My solution to the problem is 3 fold. 1) less aggressive camshaft... better valve control 2) bigger turbine wheel (less backpressure), 3) Fuel or (Fuel & Spark) Rev Limiter & Boost Cut (prevents gnarly explosions in the turbo manifold)
I believe the ignition in the exhaust manifold during the spark cut rev limiter generated enough back pressure to push the exhaust valves open and strike the intake valves... causing 1 of them to bend. I can see witness marks on the face of the exhuast valves from where they have hit the edge of each intake valve.
My solution to the problem is 3 fold. 1) less aggressive camshaft... better valve control 2) bigger turbine wheel (less backpressure), 3) Fuel or (Fuel & Spark) Rev Limiter & Boost Cut (prevents gnarly explosions in the turbo manifold)
Dec 15, 2014, 11:21 AM
#71
Evolved Member
S3's, 8800rpm, 7670 with itty bitty turbine wheel @ 320kpa (tons of backpressure), combined with a spark cut rev limiter.
I believe the ignition in the exhaust manifold during the spark cut rev limiter generated enough back pressure to push the exhaust valves open and strike the intake valves... causing 1 of them to bend. I can see witness marks on the face of the exhuast valves from where they have hit the edge of each intake valve.
My solution to the problem is 3 fold. 1) less aggressive camshaft... better valve control 2) bigger turbine wheel (less backpressure), 3) Fuel or (Fuel & Spark) Rev Limiter & Boost Cut (prevents gnarly explosions in the turbo manifold)
I believe the ignition in the exhaust manifold during the spark cut rev limiter generated enough back pressure to push the exhaust valves open and strike the intake valves... causing 1 of them to bend. I can see witness marks on the face of the exhuast valves from where they have hit the edge of each intake valve.
My solution to the problem is 3 fold. 1) less aggressive camshaft... better valve control 2) bigger turbine wheel (less backpressure), 3) Fuel or (Fuel & Spark) Rev Limiter & Boost Cut (prevents gnarly explosions in the turbo manifold)
Excellent forensic skills. I'd naturally side with #3. I'm a bit too much like jeremy clarkson and would want to avoid #1 if at all possible lol.
Dec 20, 2014, 06:23 AM
#73
Bent valve, thats nuts. What valve springs are you running? I make ~800 with Retard-rev, ignition, and fuel cut as a rev-limiter at 9000rpm, never bent a valve. Also have 288 cams (more duration than the s3)
I point to valve springs. Get some Ferreras if you don't have them. /done
I point to valve springs. Get some Ferreras if you don't have them. /done
Dec 21, 2014, 01:26 AM
#74
It's usually a seat pressure problem.
I got GSC valve spring set with seats and retainers and they were well under the advertised seat pressure. I think we ended up using 40thou shims on the intake and 60thou on the exhaust to get them to 100psi seat pressure.
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