New stroker results
12-19-2011, 01:07 PM
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New stroker results I finally got some early results from my stroker build that has been going on for most of this year. Mods are:
06 GTO 6-speed stock gears
ERL stock sleeve 421 shortblock (4.03" bore x 4.125" stroke)
Cloyes single roller timing chain
Melling 10296 with lower pressure spring
AFR 230v2 62cc heads untouched upgraded 8019 springs
Manton 11/32 pushrods
Custom cam speced by Patrick G 243/247 112+2 HUC lobes
Tuning was also done by Patrick G
FAST 102 ported by Vengeance Racing
Yella Terra rockers
LS9 injectors
ported stock throttle body
Kooks 1.75 headers, no cats
Corsa Sport catback 2.5"
SLP pully
SNL 4" intake with 100mm MAF
255L fuel pump
Compression is 11.65. We are still having some issues with what I think is the rockers hitting the valvecovers. The car stumbles like it is hitting a rev limiter at 5800. It shouldn't be valve float since I'm using good springs and the softer HUC lobes. But is is making some pretty good power until that point. I wanted to build a motor that had good torque in the midrange, fun to drive and to get the heavy goat moving at almost any RPM's. I set out with a goal of 500rwhp and 500rwtq.
I think it turned out pretty good considering the issues still left to fix. And I think I could squeeze out some more with a 102 TB and 1 7/8 headers.
Patrick G was awesome to deal with. Very understanding and went above and beyond trying to get not only a good tune but a really good street manners tune. I would recommend him and Kurt from the shop any day of the week.
06 GTO 6-speed stock gears
ERL stock sleeve 421 shortblock (4.03" bore x 4.125" stroke)
Cloyes single roller timing chain
Melling 10296 with lower pressure spring
AFR 230v2 62cc heads untouched upgraded 8019 springs
Manton 11/32 pushrods
Custom cam speced by Patrick G 243/247 112+2 HUC lobes
Tuning was also done by Patrick G
FAST 102 ported by Vengeance Racing
Yella Terra rockers
LS9 injectors
ported stock throttle body
Kooks 1.75 headers, no cats
Corsa Sport catback 2.5"
SLP pully
SNL 4" intake with 100mm MAF
255L fuel pump
Compression is 11.65. We are still having some issues with what I think is the rockers hitting the valvecovers. The car stumbles like it is hitting a rev limiter at 5800. It shouldn't be valve float since I'm using good springs and the softer HUC lobes. But is is making some pretty good power until that point. I wanted to build a motor that had good torque in the midrange, fun to drive and to get the heavy goat moving at almost any RPM's. I set out with a goal of 500rwhp and 500rwtq.
I think it turned out pretty good considering the issues still left to fix. And I think I could squeeze out some more with a 102 TB and 1 7/8 headers.
Patrick G was awesome to deal with. Very understanding and went above and beyond trying to get not only a good tune but a really good street manners tune. I would recommend him and Kurt from the shop any day of the week.
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07-07-2012, 12:12 PM
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GTO's done have 2" headers, not with out having a custom set made. If i was going all out HP then the 1 7/8 would have been better. There was someone selling the kooks Sig Series stepped headers coated for a good deal so I got them. I would have gained maybe 5hp with the bigger headers at my power level, at the expense of some midrange torque.
07-09-2012, 08:41 PM
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I think what solved it was shimming the valvesprings. I went thru and measured the installed height on the springs and they were high, 1.825 intake and 1.83 exhaust. So I shimmed them .060" that that took to around @.050 before coil bind.
07-09-2012, 08:44 PM
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Oh, and I'm not sure it is 100% solved. I had one dyno run is last time that showed a small dip at 5800 but all the rest were clean. Plus the engine still starts to fall off pretty good at 6000 were it should pull out a bit farther with the HUC lobed cam.
