SweetnessGT wrote:-Z Yaaaa- wrote:Whalesac wrote:Head flow is the biggest obstacle and is what needs the most attention with these engines.
ding ding ding! we have a winner!
Take it from me - when you overport the head on this engine it becomes a dog below 3000 rpm.
As much as my car comes to life in stupid ways at around 3000 rpm it is completely useless below that... I know that the 7.9 static compression ratio destroyed what bottom end I had left. I actually had to crank up my off-idle timing by 6 degrees just to get the car to respond decently from a dead stop.
Even when N.A with secret cams this head responded beautifully in the top end but I actually lost time in the 1/4 mile. It's the reason I ended up going boost, the car was such a disappointment N/A. There's pictures floating around of the size of the ports but it's 1/8" OVER gasket match. I'm actually making custom gaskets in a week or two and porting my new turbo manifold to match the head - I have a lot of meat to take out of the flange.
Cody - as mentioned these blocks can take a decent overbore but not whats required to increase the displacement to 2.6L. The oil pump swap is a must and as much as my JBP pump has done the trick it's my one real regret with this engine - not going with the 2.3 pump swap.
The oil pump gears were hardened due to Mike Karas shattering his above 7000 rpm - my engine was built for an 8000 rpm redline with solid lifters and custom springs. I didn't want to risk the gears coming apart at high RPM's like what Mike had experienced. I have safely brought it up to 8000 rpm quite a few times with Darren in the car to experience it... now that I know a lot more about the oil pump design on the LD9 I'm wary to do it very often due to cavitating the oil... a different gear in my pump isn't going to overcome its poor design in this regard. While the top end can take it as well as the rotating assembly I worry about the oil, now.
John/Brad - I had a pretty complete list up on the .org for quite a few years... let me know what questions you may have. Brad - a lot of the parts I mentioned you've known about for 7+ years, don't act surprised. How long have you asked me about that custom crank as well as the thermal coatings that were applied to the head and pistons so I could run a bit leaner? What about the custom bearings I had made when I blew the first engine up? You were the first person I talked to about that after I came to grips I grenaded a $10,000 engine... haha.
If i were to do it again I'd make 3 changes:
- Different turbo. (As much as I love the Borg my compressor map shows me it's going to fall short of my original goal.)
- 2.3 pump swap
- Higher SCR: the car was built for 28-30 PSI on PUMP gas (which I now know my turbo cannot support) and I dramatically underestimated the effect of such a low SCR for regular street driving.
Cody - you mentioned a TVS blower on the LD9... I personally wouldn't go any route where I can guarantee I can cool the intake charge. This is why I settled on a G-LADER supercharger for my side project... though they are known to be unreliable if you don't care for them and good for only 300 hp CFM flow. (Perfect for what I have in mind, though.) If you're going to do a built I'd suggest planning it around a turbocharger from the get-go.
-Chris-
Addicted to meth wrote:Interesting information.
My car doesn't get below 20 psi at idle, but that is getting the reading from the block not the head. Cruising it doesn't go below 50 psi.
I myself would rather make all my power below 7k. I don't want to rev above that if I can make the power that I want.
Your build is just another that proves that the stock oiling system can make good power.
I'm not saying in no way that there isn't gains to be had with a 2.3 oiling swap, just it can be done without.
I didn't know you were on solid lifters either.