Re: Procharged small block, boom.
 

I have a LM-1 meter with a wide band O2 sensor. I had adapters made that go between the manifold and riser for the sensors. AZM reprogrammed my ECU and said to run stock fuel pressure, it is 37 at idle and 40ish at wot.

Re: Procharged small block, boom.
 

I agree the fuel pressure seems to low at wot. Are you using an Aeromotive fuel pump with the ProCharger? My fuel pressure is in the 70's at wot.

Re: Procharged small block, boom.
 

Mine is around 30 at idle and close to 60 at WOT, I am using stock mercruiser pumps in mine. I have done plug checks at various RPMs and they look great.

Re: Procharged small block, boom.
 

With the re flashing of the ECU you don't have to jack up the fuel pressure to get the right mixture. The pulse is now longer to let in the right amount of fuel to compensate for the boost and added cubic inches. Before the re flash my fuel press was at 60. I don't use the boost sense line on my FMU now.

Re: Procharged small block, boom.
 

My guess is you're experiencing the limitations of the intake system and stock cam. Your boost is due to the high restriction, you're really not moving much more volume of air than you were. You do have a lot more torque at lower RPM, so go up in pitch and make use of it. That intake is very restrictive. You're probably leaving 100 HP on the table with that setup. Your speed is indicative of about 525 HP at WOT. Your engine should make near 600 with the correct intake and cam setup. Come see me and we can experiment :D

Re: Procharged small block, boom.
 

Another thought, what is your timing running at total advance? You may be needing some more timing. It would be nice to make a run with a computer with diacom installed and log the data to see what is really going on. Those aluminum heads may change your timing requirements some.

Re: Procharged small block, boom.
 

Is his mpi intake the cast iron one that resembles a cast iron 4bbl intake ?

BTW: by notes which I have Merc roller cam with spec's below. Unfortunately, I do not have listed if this is what they used for the MPI motors or just the 2bbl motors. If it is for MPI motors also, then, yes, there is a lot to be gained by swapping it out.

Stock hydr roller
.004" 258, 272
.006" 249, 264
.050" 197, 207
.430", .450
109 LSA

Re: Procharged small block, boom.
 

Only running about 28* of timing right now. I am a little gun shy of more due to the condition of the last motor. I'm sure I will start bumping it up as I get some more hours on it. I will probably do a cam change in the off season. What would you guys recommend?

Re: Procharged small block, boom.
 

Blowncrown,
Use caution when excessively retarding timing to control detonation. When timing is reduced your EGT's will increase dramatically per given boost/AFR/CR. The elevated exhaust valve temps may result in valve failure or creating the very detonation you are trying to avoid. It is very possible you will end up swapping one catastrophic root cause for another.
Bob

Re: Procharged small block, boom.
 

The intake is the Vortec truck intake with the TB on the front. It has runners that loop around for good low end torque. They use that same hydraulic roller cam in all versions of the 5.7.

RMBuilder...keep in mind he is using the Edelbrock ETEC heads which I believe are a fast burn design similar to the GM Vortec so they don't need a lot of timing. He would probably be OK with a couple more degrees of timing since the heads are aluminum. IMO.

Blowncrown, I still think you're a little lean on that A/F. I like to see around 11.5 under boost. Maybe you could bump the fuel pressure up a couple of pounds. It won't make any more power but may live a little longer.

Re: Procharged small block, boom.
 

Here's the dyno run I did on the 383 with a Whipple and 800 Holley. This was at a little over 5 psi boost. It has a Crane 109831 hydraulic roller and vortec heads. This is running in complete marine trim with stainless marine manifolds running wet.

Re: Procharged small block, boom.
 

Ahhh, so it's a new MPI. Dang - I don't like that intake much. I do like the cast iron one that's typically found on the 6.2MPI's though. Great with a carb on top of it. Ooops - just spilled a scret. LOL.

Re: Procharged small block, boom.
 

Those are impressive #'s !!! That thing was still building power, which makes me ask, why is the torque peak more than 2000rpm below the HP peak? With that much torque, maybe it really wouldn't matter in a smaller boat.
The cam in your motor has 18 and 16 degrees(respectively) more duration than Blowncrown's cam. In fact that 196/206 cam is what GM uses in their 383 Vortec headed crate motor which HP. peaks @4500rpm. It looks to me like he needs about 10 degrees more duration.

Re: Procharged small block, boom.
 

[QUOTE=LMAC]Those are impressive #'s !!! That thing was still building power, which makes me ask, why is the torque peak more than 2000rpm below the HP peak?


Yeh, I wondered the same thing. My assumption is that the SC just builds so much low end torque that it shoots that whole 1200 rpm peak torque to peak hp theory out the window. I was tempted to run it on up to 6000 to see what it would do, but I don't plan on turning more than 5600 so anything above that doesn't matter anyway.

Blowncrown is running a procharger so it won't have the low end torque that the Whipple does, but probably surpass it at higher RPM.

Re: Procharged small block, boom.
 

The intake on my motor looks like a 4 barrel intake with the throttle body where the carb should be and injectors in the runners.

Re: Procharged small block, boom.
 

Oh, good. All this time I thought you had the later model intake. That can make a lot more power. Guess you just need a better cam.

Re: Procharged small block, boom.
 

Schweet !!!!

The dude's got the good intake !!!!

Let's cam this beatch up !!!! :evilb:

Joking - kind of :D - do what you want. It's pretty stout as it is.

http://imagescommerce.bcentral.com/m...yvorteccai.jpg

Re: Procharged small block, boom.
 

Ok lets put a cam in it! Which one? Like you Bob I don't want to spin it past 5600 or so. Or just fast enough to get me past you know who. :D

Re: Procharged small block, boom.
 

I'm kinda partial to the one I used in these 383's. It's a Crane 109831. I erroneously posted earlier that I had the 821 cam in these engines. If memory serves me right it's .509/.528 lift and 222/230 @ .050 duration with a 112 LSA. That's about as big as I would go. It hasn't killed my 02 sensor idling on the dyno, so I don't think it will revert water badly, although I do have Stainless Marine exhaust on it. The 109821 is a little milder and may be a better choice. I've had one of those running in a Whippled 6.2 for 3 years now. The 6 .2 came stock with the 104224 cam.

Re: Procharged small block, boom.
 

Bob, I noticed on the dyno sheet the A/F ratio is down in the 11.2's. Should I have mine running that rich?

Re: Procharged small block, boom.
 

Never mind Bob, I just read it in your previons post. 11.5

Re: Procharged small block, boom.
 

How about this one?
Part # 10185071

Duration @ 0.050" Lift: 208/221
Lift: .474"/.510"
Lobe Separation: 112

Type: Hydraulic roller tappet

Re: Procharged small block, boom.
 

It would work OK. IMO But you could probably do better. You've got pretty good heads so I'm not sure you need that big of a split even with the SC. I'd like to see a little more duration. Of course if you can get one cheap that impacts the decision. Maybe SB or Rmbuilder will chime in. They know much more than me about camshaft design.

Re: Procharged small block, boom.
 

I'm clueless with blown applications - I'll admit....again. LOL.

Blowncrown - that Part # 10185071 is from the ZZ4 crate motors. Those use the old aluminum Corvette heads. Engine makes okay power because of high compression + okay 'yesterday's' heads. Totally different head then you have now.

BobL - the crane you mentioned is a favorite amongst many 383 + 406 SBC marine build ups.

I just don't know these Edel heads + do not know what the camshaft demands would be for a centrifugal S/C with this set-up. RMBuilder + probably Tomcat would have more insight.

So................I'm watching this thread myself. Always need more data. :D

Re: Procharged small block, boom.
 

Yeah,
214/222 duration sounds a bit small to be able to turn 5600+rpm.

Re: Procharged small block, boom.
 

I ran that cam in my first 383, with 2.02/1.60 Torquer heads.
It built power to about 5000rpm. But like BOBL said, you don't need 13 degree split. Those E-tech 200 heads apparently have some very good exhuaust ports, so probably a 6 degree split would be plenty.
I've got a 383 with a comp 224/230 HR. It builds power on the Dyno to 5400rpm. This may be more cam than you need with your SC.

http://purplesagetradingpost.com/sum...fo/heads1.html

http://www.bulletcams.com/

Re: Procharged small block, boom.
 

Do you have to use aftermarket lifters with these cams or will stock lifters do?

Re: Procharged small block, boom.
 

You got me to doing some research. It appears that Merc uses the 831 cam in the scorpion 377 racing engine. The parts manual shows the stock GM lifters being used. I know I used them on the 6.2 with the 821 cam. So, they shouldn't be an issue.

Re: Procharged small block, boom.
 

You guy's sure are handy to have around! Thank you very much for all of the info!

Re: Procharged small block, boom.
 

OEM style lifters are fine with a standard size base circle (approx 1.180") all the way down to 1.050 . Anything smaller will require the use of a longer lifter body. If you are going to replace your lifters, In my opinion I would stay away from the Sealed power/Speed pro #2148 and spend a little more and get Comp, Crane, Morel etc...

Re: Procharged small block, boom.
 

I think we can say the same exact thing to you !!

Thank you.

New / different builds with shared info is totally appreciated. More high quality data / info is always better than less. :D

Re: Procharged small block, boom.
 

There is a lot of good info on my project with some photos that you might like to chech out over here http://www.crowniehq.com/forum/showthread.php?t=581

Re: Procharged small block, boom.
 

So any updates????

Re: Procharged small block, boom.
 

I don't think Blowncrown get's on here much, so I'll speak for him. He got it running, and it is working nice. However he left the stock cam in and the engine is laying down pretty bad at higher RPM so he's not getting much more speed than when it was a 350. He said it really accellerates a lot harder. I think he's planning a cam change this winter.

I've got a couple of similar projects here at the shop now. 2 carbed 383's with Whipples. I dynoed them at 575 each. Also just starting on building a 350 Mag into a 383 stroker for another customer.

Bob

Re: Procharged small block, boom.
 

Good talking to ya Bob, I'll see ya in a few weeks.

Re: Procharged small block, boom.
 

Bob said it all, cam and fuel pump upgrade over the "off season".

Re: Procharged small block, boom.
 

I didn't mean to speak for you Tom. Haven't seen you around for a while so I was afraid you wouldn't see it.

Re: Procharged small block, boom.
 

No sweat Bob.

I'll try and keep you guys updated as I get things done.

Re: Procharged small block, boom.
 

bobl, When you used the Crane 222/230 Crane HR cam, what idle rpms were you seeing in and out of gear? I'm leaning towards this cam for my new 355 build. I just hope I can get it to idle around 750-800rpms.

Re: Procharged small block, boom.
 

This is the same cam Merc uses in the Scorpion 377, although it is fuel injected. I haven't had this boat in the water yet, but it idled pretty smooth on the dyno. Using it in a 350 will be a little more radical. I ususally use the next size smaller cam in the 350's. So much depends on the heads and desired operating RPM.