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Something wicked this way coming from HPR to the FNBADAZ06
C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Looks great! Which crank/rods? Small journal? Which CR are you shooting for? Last, intake?
K1 crank and rods, spec'd by HPR for the 468 builds.
I thought about a small journal option, which is what Jeremy's (441LSXTT) is using, but didn't go for it.
I spec'd my heads for a 65cc chamber, and HPR ordered the custom pistons to get a 13:1 compression with standard head gaskets. Jeremy's setup is the same compression, but I believe they needed to use a thinner head gasket to get the compression there as his chambers were a tad bit bigger than mine.
For intakes, I'll be moving to the new FAST 103HR high ram unit I'll be matching this to a Southways 108 throttle body, which should be enough of an intake combo to reach my 7000-7200 RPM peak HP range.
I still have my Mamo MSD and NW 102 throttle body as well, and my desire is to install both units on the engine when doing the engine dyno test so you can see the direct comparison. We know that Jeremy's 468 with the MSD/NW102 combo ran out of air before 6400 RPM, but it still managed to crank out 680/620 on a chassis dyno !!!!
I'll be running a similar hydraulic cam as Jermey's, but a little more customized to take advantage of the head flow numbers, FAST/108 TB, and the fact that I have 3.90's and a race weight in the 2900 lbs area.
Should be some fun testing coming in January/February
I blew both OEM and remanned alts on mine when spinning over 7000+. Installed a billet tech and no more issues. Plus my voltage is MUCH more stable over all operating conditions than before. A 10% reduction may help your alt...but really is not that much of an rpm drop especially since people blow them with the stock rev limit let alone a raised one. Yes it is pricey but my electronics are happier (injectors, fuel pump, etc) and my battery will last longer as it is now getting a proper charge voltage at all times (14.4+).
I blew both OEM and remanned alts on mine when spinning over 7000+. Installed a billet tech and no more issues. Plus my voltage is MUCH more stable over all operating conditions than before. A 10% reduction may help your alt...but really is not that much of an rpm drop especially since people blow them with the stock rev limit let alone a raised one. Yes it is pricey but my electronics are happier (injectors, fuel pump, etc) and my battery will last longer as it is now getting a proper charge voltage at all times (14.4+).
I went over 90K miles on my original alternator, with more 7000 RPM pulls than I care to count. Coincidental or not, once I started spinning up to 7300-7500, I lost a few replacement units once my original gave up the ghost.
I'm thinking about several brands of upgraded units.....seems like I've seen a number of post lately regarding failures on Mechams.
Fair for sure - everything has a failure point. If I had not already been running a standard ati unit I would have gone 10% ud but also liked that the full size offers "better" damping abilities due to rotational mass.
I lost my oem racing a 720S in Mexico - was worth it.
Fair for sure - everything has a failure point. If I had not already been running a standard ati unit I would have gone 10% ud but also liked that the full size offers "better" damping abilities due to rotational mass.
I lost my oem racing a 720S in Mexico - was worth it.
I currently have the standard ATI non-underdriven unit too
Just get a bigger alternator pully and save your time than having to do an UD pulley. I went from a 60 mm one to like a 65 or 67 mm one does the same thing. Once the alternator gets over 20K rpm bad things begin to happen. With a 7.5 inch balancer and a 2.5 inch pulley 7K equate to 21K of alternator speed.
I also need to decide if I want to switch to a 10% underdriven ATI balancer.
I lost my OEM alternator during a 1/2 mile event last year, which was replaced with several different "re manufactured" units from A/C Delco and Autozone. All failed within a few weeks when I spun the motor up to 7300+ RPM during my test runs.
I had heard that the re manufactured units could not stand up to repeated high RPM usage because of inferior bearings used in the rebuilds, which allows excessive heat to build up and allows the internals too much movement inside the case.
I also have friends who mostly run HPDE's , where engine speeds are almost always in the 5000-7000+ range for 15-20 minute sessions at a time, and they lose alternators on a regular basis. Many of them under drive the alternator as one of the fixes, but these are more track cars than street cars, so idling at a traffic light is not a concern for them.
edit: Good advice above, for some reason those responses didn't show when I replied until after I replied.
I just bought a new OEM alternator before the tear down began, and with the switch to an electric water pump, I don't have the concerns of coolant circulation at idle and low engine speeds, but I'll also be adding to the electrical load on the alternator.
The underdrive balancer will slow the alternator down which appears to help significantly with bearing and overall life span (these things are expensive ), but I may need to upgrade to an aftermarket unit to supply the electrical demands of the water pump and the new Prospeed dual Spal fan setup I'm putting on the car.
I have similar concerns and decision with the 10% under drive depending which direction I go with the build (still waiting for one last call...). One thing I looked at was my idle speed with the larger camshaft was 925 rpms so I think that will offset the under-driven amount enough where charging should not be a big problem. Engine cooling is more of a concern for me in the hot humid temps and FL traffic since with the regular pully the temps would start to creep until the fans were programmed to come on a touch sooner than the factory settings.
Just get a bigger alternator pully and save your time than having to do an UD pulley. I went from a 60 mm one to like a 65 or 67 mm one does the same thing. Once the alternator gets over 20K rpm bad things begin to happen. With a 7.5 inch balancer and a 2.5 inch pulley 7K equate to 21K of alternator speed.
I have similar concerns and decision with the 10% under drive depending which direction I go with the build (still waiting for one last call...). One thing I looked at was my idle speed with the larger camshaft was 925 rpms so I think that will offset the under-driven amount enough where charging should not be a big problem. Engine cooling is more of a concern for me in the hot humid temps and FL traffic since with the regular pully the temps would start to creep until the fans were programmed to come on a touch sooner than the factory settings.
I hear you bud........AZ gets pretty frickin' hot.
I picked up a DeWitts Z06 radiator and the Prospeed dual Spal fan and shroud for my car as well. The electric water pump will be moving more coolant at low engine speeds as well, so I should be good.
Powermaster or March has some and I got mine from summit my alternator has a 17mm (.667-.669) press on pulley shaft so I search 17 mm and 67 mm (2 5/8) in diameter. They also have a 70 mm in diameter. If you have a clutch alternator that may need something special. The stock size balancer pulley is 189 mm so you can do math too see which one you want.
I hear you bud........AZ gets pretty frickin' hot.
I picked up a DeWitts Z06 radiator and the Prospeed dual Spal fan and shroud for my car as well. The electric water pump will be moving more coolant at low engine speeds as well, so I should be good.
I have an electric water pump in my race car and it is great. I have a manual switch that I can turn on with the car off and run the pump and fan at 50%. Talk about cooling en engine down nicely between runs! Great thing!
I also need to decide if I want to switch to a 10% underdriven ATI balancer.
I lost my OEM alternator during a 1/2 mile event last year, which was replaced with several different "re manufactured" units from A/C Delco and Autozone. All failed within a few weeks when I spun the motor up to 7300+ RPM during my test runs.
I had heard that the re manufactured units could not stand up to repeated high RPM usage because of inferior bearings used in the rebuilds, which allows excessive heat to build up and allows the internals too much movement inside the case.
I also have friends who mostly run HPDE's , where engine speeds are almost always in the 5000-7000+ range for 15-20 minute sessions at a time, and they lose alternators on a regular basis. Many of them under drive the alternator as one of the fixes, but these are more track cars than street cars, so idling at a traffic light is not a concern for them.
I just bought a new OEM alternator before the tear down began, and with the switch to an electric water pump, I don't have the concerns of coolant circulation at idle and low engine speeds, but I'll also be adding to the electrical load on the alternator.
The underdrive balancer will slow the alternator down which appears to help significantly with bearing and overall life span (these things are expensive ), but I may need to upgrade to an aftermarket unit to supply the electrical demands of the water pump and the new Prospeed dual Spal fan setup I'm putting on the car.
I run an ATI 10% UD and spin mine to 7500+ (tagged the 7700rpm limiter a few times) at least a few times weekly. OEM 44k mile alternator still chugging along. Didn't have any issue when my electric water pump was on (and working). Still great charging voltage. You can raise your idle a tad to compensate for the pulley if need be. I would definitely grab one.
Very anxious to see this combo. Are you going to test Josh's old hi ram on the engine dyno? That would be a great comparison with the FAST. I think the hi ram still might make more power though. I guess only time will tell.
I loaned my 108tb to Jason @ TSP. He wanted to test it on his max effort LS3 engine. I'll be installing that, the TSP 1.82 ratio rockers, and a lighter clutch (Mantic twin); next. Still not sure what route to take with my motor. These 468ci motors are very enticing but N/A alone isn't going to cut it. LOL.
Impressive #s, do you know if the exhaust was flowed with a pipe? and if so what size?
I don't know the answer. WCCH has a Facebook presence so they might have pics of the flow bench and the actual process of flowing a head.
The heads should arrive on Friday, so hopefully we can test fit the Comp dual conical springs to see if they will fit.......then HPR and Billy can discuss cam specs
Another cool thing of note is that after HPR identified some clearance issues with the Brodix heads when using 7/16 push rods, I believe Richard created an updated CNC program to include the clearance for these larger push rods as part of the standard package
On there website flow numbers they say they are not tested with any pipe. Not sure what they did here. Also they mention on website some kind of intake flange I think.
I'm hoping we see a manifold show up sometime in the next few weeks too. I still have my Mamo ported MSD and NW102 throttle body, and we saw how that combo performed on Jeremy's engine....peak power coming in under 6400 RPM.
My cam may end up being the same as Jeremey's, or fairly close, given the heads are pretty much twins....... different springs being the only real difference.
My car setup deviates from his with mine having an electric water pump, ID1050x injectors, a planned different intake and throttle body, and a 3.90 rear axle ratio.
12-28-2018, 12:32 PM
I'll be matching this to a Southways 108 throttle body, which should be enough of an intake combo to reach my 7000-7200 RPM peak HP range.
), but I may need to upgrade to an aftermarket unit to supply the electrical demands of the water pump and the new Prospeed dual Spal fan setup I'm putting on the car.
