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So I just got my D1SC Procharged Camaro back from the dyno tune and was very underwhelmed. 590rwhp just won't cut it with a maxed out D1SC blower. I was hoping for closer to 700 on this combo which seems to be a very realistic number. The tuner thinks it's all in the compression which turns out to be only about 9:1 on my 408 forged motor (lq9 72cc heads).
The dyno graph shows the car almost running out of steam around 6k which doesn't make any sense to me since the blower is maxing out right around 6500. The midrange power suggests this car should be at least around 650rwhp. The car makes about 8-9 lbs of boost at the boost gauge.
My question is do you think I have a boost leak (no signs of belt slippage)? Any easy way to check?
Should I get a set of milled heads and a thinner gasket? Should take me to 10.1:1 maybe as high as 10.3:1? Would that be enough to make better use out of the D1?
Or should I keep the compression low for an F1A/F1R? I plan on upgrading to an F1 soon. The low power levels are definitely making me want to do it sooner then later. Would I be better off 9:1 with an F1 blower or would I still benefit with around 10:1 compression.
Last edited by The Alchemist; Nov 13, 2015 at 01:14 PM.
Reason: Changed the title... this isn't a compression ratio problem.
93 octane. It also has a smallish blower cam, 60lb injectors with a Squash twin pump set up. I don't suspect fuel is an issue here. The fuel system is set up for 1000+hp with an injector swap of coarse.
I'd raise it to the 10's in a heartbeat no matter what headunit is on it. Technology has advanced so no need to compression that low even for 93 octane.
You won't gain too much going from 9:1 to 10:1. Something else is wrong. Going up to 10:1 may net you 30-35hp. Back in the day I had a lil HKE D1SC 347 at 8.98:1 (to be exact) put down 770rwhp and then made a little over 800rwhp peak when I went to 10:1, nothing else changed but 317 to AFR heads and a tune. What's your entire set-up?
make a boost leak tester, I use them all the time to check plumbing. I fill the turbo inlet (or supercharger inlet) with air pressure from an air compressor till it contains 20~psi (whatever you run) to find leaks. Make sure you block off the engine's crank case (your PCV route may include the crank case) the last thing you want is to push the oil seals out of the engine with air pressure.
The pressure should stay fairly easily in the plumbing. When I hit 19psi on mine it will hold for 30-45 seconds losing about 1/2psi every couple of seconds.
I agree something else is wrong with the setup. Your down 100+ hp with that size motor and a maxed out D1. I make more power on less cubic inch and I still have 10,500 RPM's left in my D1 head unit. Valve springs / valve float, boost leak, belt slip, timing ect. Is the engine healthy ? Is a compression or leak down test needed ?
Where is the boost gauge installed-good HP for the boost, but boost is low
You either have belt slip, restriction, out of injectors (60 is borderline), wheel spin, etc
If you have an intercooler, are you reading before and after boost
I had a D1SC on a 403, running a vette style setup and 8 rib belt, could get over 13 lbs boost
on my turbo car on the street my 60 lb injectors would run 114%, I changed them to 120's
There must be a lot wrong with this setup...
My first thoughts, is the blower healthy?
What induction on the inlet to the blower? If it's restricted, that explains the low power.
Intake piping... what size, lots of bends, is it leaking?
Exhaust... is it free flowing?
Belt setup? Is it a 6 or 8 rib? Which bracket and tensioner are you using?
Since you are seeing low boost pressure, my guess is you have either a hurt blower, an inlet or charge pipe restriction, a leak somewhere, or belt slip.
Sure, 10:1 would be better than 9:1, but you're missing a solid 150rwhp.
I made 760/700 with a d1 on my 347, and that was with a slight boost leak above 15psi, slipping belt (it was old tired), very rich afr (mid 10s) and modest timing (15 degrees). Optimized, I was looking at an 800rwhp setup.
A D-1SC on a 408 can make 16 psi of boost, you definitely have some problems with your combination. Answer the questions in the post directly above mine, and we can help to solve the problems. Bob
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This is what I was afraid off, as it seems like it can be a handful of problems. At 590rwhp we weren't running lean at all on the 60lb injectors. They are 3bar 60lb injectors so they should be fine for now (planning on swapping them with the head unit). It is a 8 rib set up with the factory Procharger bracket 7.65 crank pulley and a 3.8? blower pully. I originally thought belt slippage but the pulleys are clean. It is however running the factory twin intercooler set up. I thought this would hold me back somewhat but I have seen guys running 650+ on them. My tuner also said timing was not an issue. I'm guessing it's probably a combination of a few things. Maybe the compression being to low and the crappy intercooler set up? What front mounts do you guys recommend/run?
Also, the engine is a brand new 408 iron block set up built by Livernois. The heads are Patriot CNC'd 317's with dual valve springs and the whole 9, topped with an LS6 intake. I really doubt the issue is internal as the car runs real strong. The exhaust should be fine. 1 7/8" long tubes, no cats with an SLP Powerflo catback and a cut out that was open for tuning.
I believe the dyno would suggest this car makes better power when looking at the mid range. Comparing it to my buddies 612rwhp Vette (A&A kit). It makes better low end and midrange power up to around 5500 where mine falls off.
Last edited by JASON11WS6; Nov 11, 2015 at 09:12 AM.
This is what I was afraid off, as it seems like it can be a handful of problems. At 590rwhp we weren't running lean at all on the 60lb injectors. They are 3bar 60lb injectors so they should be fine for now (planning on swapping them with the head unit). It is a 8 rib set up with the factory Procharger bracket 7.65 crank pulley and a 3.8? blower pully. I originally thought belt slippage but the pulleys are clean. It is however running the factory twin intercooler set up. I thought this would hold me back somewhat but I have seen guys running 650+ on them. My tuner also said timing was not an issue. I'm guessing it's probably a combination of a few things. Maybe the compression being to low and the crappy intercooler set up? What front mounts do you guys recommend/run?
Also, the engine is a brand new 408 iron block set up built by Livernois. The heads are Patriot CNC'd 317's with dual valve springs and the whole 9, topped with an LS6 intake. I really doubt the issue is internal as the car runs real strong. The exhaust should be fine. 1 7/8" long tubes, no cats with an SLP Powerflo catback and a cut out that was open for tuning.
I believe the dyno would suggest this car makes better power when looking at the mid range. Comparing it to my buddies 612rwhp Vette (A&A kit). It makes better low end and midrange power up to around 5500 where mine falls off.
That squiggly line in the upper rpm range is a sign of belt slippage, as the belt slips, then grabs. With the ProCharger J Bracket you have to run the blower belt much tighter than what you are use to with other belts. It basically needs to be as tight as a guitar string. Anytime a new belt is installed, break it in by taking it easy on it for an hour. After an hour, readjust it as it will have stretched. Now it's ready to go wide open throttle. Bob
__________________ ATI ProCharger and Moser Sales 260 672-2076
How much boost could it be robbing? I'll have to tighten that belt but it seems really tight already.
Any intercooler suggestions? I think I'm going to run a new intercooler set up and work on the belt and hit the dyno again.
This winter I was planning on a heads/cam pacakge on the 2011 SS. I'll take the stock LS3 heads off of that, mill them and toss them on this 4th gen. Should get me the compression I need to get over that 700 mark hopefully.
Last edited by JASON11WS6; Nov 11, 2015 at 10:47 AM.
Your problem appears to be how much air is getting into the blower, then how much is getting to the motor. What inlet do you have on the blower? Try removing it on the dyno to see if the boost psi goes up.
Like Bob said, it looks like belt slip up top, and those twin intercoolers aren't helping either.
The problem with the static tensioner is as the rpms and load goes up, the belt stretches, now, the tension on the belt goes down when you need it the most. This is why you are losing 2, 3, 4 maybe 5psi of boost up top.
Go to a FMIC setup, get Aster's bracket setup from Bob, and I bet you'll se a good 700-750rwhp. FYI, with your pulley setup, you're still leaving some room to spin the blower harder. A 3.40" pulley is what you need.
Belt slippage going on for sure, check the entire system over well for leaks also. I once had a vacuum modulated trans that would develop a boost leak at the check valve over 9 pounds. Small things like this can really affect your efficiency.
How much boost you are losing and how much more power it will make is only relative to your particular combo, but there's no reason your setup shouldn't make in the 675 range.
I would suggest going to a better bracket and pulley setup if you are planning on a setup with over 8-9psi, or any F series blower. I would also suggest modified pulleys to aid in belt grip as well.
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PROCHARGER experts needed. 
