Moving to PRC 260cc LS3 Style Heads thanks to CPR

[TheCMSH]

excellent pointing!!!!! Bravo man!!!

[Cross]

So it seems yet another adventure has presented itself. Swapping out the Trunions we found brass/copper in 3 of them. I tried to take a picture I will post it. All I can think of is where the hell did that come from on a new motor... So now its time to pull the oil filter apart and see if anything is in there....

This motor was built by Larry's and I just got off the phone with him. He agree's its alarming but he is right I did not find it in any of the recesses in the heads or else where. I am taking the oil filter to him to cut open, he was very polite and concerned about the issue offering to help. But yet again yet another curve being thrown my way. If this crap doesn't stop I am just going to bring the damn FR-S out on a 100 shot and run that.

Either way he does have the push rods in stock that I need, now to see if we can figure out whats going on with these trunions and why there is brass/copper in them.

[TheCMSH]

#you'recurseddood

[Cross]

Alright Larry's took care of me they are warranting the Trunions and I got my push rods. Car's almost back together.

They opened the oil filter and there was nothing in it so they were not really concerned with it, since they built and would be warrantying the motor I figured I have done my due diligence if something was wrong they would have told me what to be concerned with and I did ask.

So back to getting this thing on the road!

[Cross]

Tonight's progress... and yet another challenge, the Fuel Rails need bigger spacers. I also found only 4 fuel injectors had clips on them and the ones that used the clips were barely in. The Passenger side did not have any clips on the top of the fuel injectors holding them to the rails but they seated all the way without them.

[Jon]

Proper pointing! Use good sturdy material for those spacers. Maybe a machine shop can cut you some. I've also read about issues with the Comp trunnions, so that's probably what happened.

[Cross]

Well as of right now I expect to fire it up tonight... I think we finally handled everything... knock on wood.

[Cross]

And she is alive!! Sounds really angry too lol, I like it.

[Cross]

Alright guys I have to say yesterday left me a little frustrated.

Now when we got the heads we had them cc'd and they were about 65cc so 64cc - 65cc seemed accurate. My Ported LS6 Heads were 64cc according to the build sheet from Larry's. At that cc they were 11.1:1 Compression so these being 64-65 should have been damn close to the same.

Now when I got the car it was running on 91 and this was the dyno slip I got with it:

The results of yesterday's dyno now with the new heads and the car running on E85 were this:

Now what I cannot show you is the results of the dyno when I first converted it to E85 and it was dropping to 45PSI by 5000/5500 RPM so we shut it down. However I can tell you at that point it was making 480-485HP and still going strong.

This leaves me scratching my head, how did we not gain power with a swap to these heads. I thought the other heads were 63cc chamber yesterday and I must have significantly dropped the compression but going over the build sheet today I was indeed wrong. They were 64cc. So if there was any drop in compression it should not be significant.

But to basically gain nothing from all this means either the heads I had were better or my Ported LS3 doesn't hold a candle to my Fast 102.... But something just isn't right here.

It is making more torque much sooner but yeah to not break 500 at the wheels when last time both Nic and I agreed it was on its way to do so is very disappointing. Nic had brought up a cam to take advantage of the heads but I am not looking for a peak numbers cam that's not what I want but maybe that's where I need to go.

Also I was curious about the dip at 3000 to 3500 in Torque what would cause that? There is another small dip at about 3700rpm.

[Big Poppa]

I am not an expert by any stretch, but here's what I see...

You're hitting 400 lb/ft of tq at like 2700 rpm. That's huge. That's what we chose that cam for, and what I wanted from the engine. So the new heads and smaller tb/intake are making more power down low. I think that's awesome. You can also see the better heads in the tq curve. With the old heads the tq started to fall off at 4700 rpm, now it holds all teh way to 5500. That's the better flowing heads I assume.

How does the car drive? Still having the gen 3 computer makes it less tune-able, and that probably accounts for the drop in tq you mention. The drop in TQ perfectly matches a small lean patch. My guess is Nic can't touch that in the tune, where as if it were a gen 4 car he could.

It still has a couple choke points for getting high hp numbers. You have 1 3/4" headers. Great for lower end tq and drive-ability, not as good for higher rpm hp on a larger cube engine. Next is that cam. We chose that cam for it's smooth and low tq curve. Being a stroker and a street car, I wanted a very flat tq curve and I wanted tons of power down low with a low hp peak. I wanted the engine to stay together for a long time, so I didn't want to spin it real high.

I think that dyno sheet looks fantastic. It's exactly what I built that engine to do, and what that cam is supposed to do. Peak hp hits just below 6,000 rpm. It has more tq than an LS7 all the way through. It's doing what it's supposed to do. Want more hp up top? Like Nic says, get a different cam. HP is a measurement of tq multiplied by rpm. So, want more hp? Spin it faster. But that won't make the car move any better. It'll just make you spin the engine more, which IMO is bad when you have a stroker. Learn to utilize that low down tq through a different driving style and some sticky tires. Get that car to hook, and in real world environments it will be amazing.

[Cross]

Victor thank you again, while I figured out my Monster Stage 2 does not like back to back passes... really hoping its just like an LS7 clutch and just got to hot but before that I did a 12.09 @ 121.38mph with a 1.966 60ft. Then the clutch started saying no. I just drove it home haven't been getting on it I need to do some more research but so far seems its common for L7 clutches to do this just not sure about Monster Stage 2's.

So close to 11's on street tires so close.

As for the goal I don't want a top ender but I want to get over the 500 mark and it is not pulling that off. I don't mind the torque besides it being hard to keep hooked and the clutch issue above. But I want over that 500 mark at the wheels.

[joe@cpr.com]

Cross it'll make well over 500 once you get a better cam in it. The manifold will support it as justin on azft (yellow ta) has worse heads and the same manifold on his 408 and made 505 on his old 408 setup. New setup gets tuned thur I believe and it has a custom grind from us now along with a little more compression. Also you quickly found out why we don't do monster clutches, they don't like to be actually raced and beat on. Fine for a guy who never sees the track and just plays on the street. But if your going to actually do something track related with it good luck. McLeod rst or rxt ftw!

[Cross]

Well I can assure you I am probably going to go back to Spec or pony up for a McLeod next time. I just don't want to replace the clutch any time soon... I am hoping it is alright.

[NicD]

The depression in torque is due to cam events in combination with those heads. The bigger the cam, the larger the dip tends to be and no amount of timing or fuel will get rid of those type of depressions in a dyno graph. It's making killer torque and drives well, but the cam isn't that big so that's what you should expect. A bigger cam will make more power up top in exchange for bottom end torque so it all depends on what you are after.

[Cross]

I like the low end Torque I really do, I am not sure my clutch does but I do

But I do want to cross the 500 mark NA so it needs to be adjusted and optimized for the new heads. I also want a cam that would be good for Nitrous or a Supercharger as I have a feeling I will end up doing both or just going straight to a Supercharger.

[Jon]

Leave the cam. Add blower. Done.

[Cross]

Leave the cam. Add blower. Done.

I was just thinking about that yesterday... A&A Setup with 5-7Psi.

Hey Nic how safe would that be on this motor? (Or Joe or Steve)

[Jon]

That cam will work great with a blower. A little more overlap than I personally would like to see, but well within the range of what people spec for centri blowers. It's basically a blower cam if you want to look at it like that. It will drive great and pick up a shit ton of power. Get the ECS kit that uses the restrictor plate if you want even more torque. The A&A T-trim is the same blower as the ECS1500, but A&A doesn't use a restrictor plate. They use a larger blower pulley instead which gets you less torque if you want to keep boost in the 7psi range. An ECS car with the restrictor plate usually makes about the same torque as HP. An A&A car at that boost level will make about 50-75rwtq less than the rwhp since you aren't spinning the blower as hard as the ECS kit with the 3.25" pulley and inlet restrictor.

[Unreal]

Factory LS7s are 11:1 and cast junk pistons and take 6-8psi just fine, make 650-750rwhp reliable for awhile (until they drop a valve). I would see no issues running 5-6psi and making 600-680rwhp for a long time on this motor.

[joe@cpr.com]

You would be able to run a blower kit as long as you didn't get greedy with the power. I don't know the compression of the motor but it can't be anything to crazy based on the hp numbers and the fact it can be run on pump gas. We are in pretty deep w/ ecs ;)

[Cross]

I like the ECS Setup in some ways and not others but after how the owner acted on CF Forums and LS1tech I am not sure I want to support him. I think both threads got deleted but I really was surprised how he handled himself. It would be the equivalent of you telling the guy who sent you the Camaro in your shop last time I was there that he should hang up his tools and get his car the hell out of your shop. (Something you would obviously never do but it just floored me)

Either way Honeymoon and the recovery from the wedding first then widebody rear fenders and then I will decide if I switch directions this close to having nitrous ready to run and go FI or not. But one of those style kits would be nice.

[Unreal]

I've dealt with Doug a lot. He is freaking awesome. He has sent me parts when I should have paid, etc. I read those threads but gladly would go back and push him. They are much better than A&A kits.

[Cross]

So then what really happened there, I have never dealt with him that was my first impression and it was a WTF.

I have heard more than once that the kit is the better of the 2 but then seeing another local (Dange) buy a kit from him and parts were late shipping then missing just added to it. Things happen but those two incidents are what made me say no to him. He basically flat out said if they didn't build the car it was most likely junk and they did not want that in their shop.

[Unreal]

I read it all. I'm sure he had good reason. Plenty of people bring complete POS cars in then expect a shop to fix all the issues. He stood up for once and got blasted for it.

If you want a better kit and great customer service then Doug/Chris are great. If not go with a different kit. Plenty of people have had issues with A&A too. The procharger kits need a bunch of upgrades but can be made to make decent power.