Can't hear tone over the intrawebz, my apologies.
From all the reading I have done, and people I have talked to, the ideal port on an s/c car is far different from turbo/na.
Comparing lnf to lsj is moot.
For max power numbers, bigger is better (to a point,yes)
We have, on an sc car, boost shoving more air in with relatively no backpressure when compared to a turbo car. Scavenging isn't as critical.
We can't run the ext duration that a turbo/na car can effectively, so to get exh out we use a large port and high lift exh cam. We can go bigger on the port because, since the flow is self scavenging, we can sacrifice some velocity to get the exh out.

In terms of flow, think of it like injectors. They flow based on pressure differential. Same with the air in a cylinder.
The inlet pressure of the air charge vs the restriction it faces exiting is a far greater span than a turbo car that is otherwise identical. Flow is greatly in our favor.

the point I am making is the LNF ex port is tiny compared to stock LSJ is all. LNF produce big power numbers.

So for forced induction motors, port flow numbers are a different, not as critical issue than extracting power from a n/a motor. And you have found that turbo SAAB heads have small exhaust ports. Now it then causes you to think, that if the exhaust port is made bigger than even the GM ones, the inlet would have to be changed as well.

GM, to make big numbers ( 400 hp) BITD arrived at "leave inlet alone, open exhaust, thats the cork".

spend more money? gotta maintain the balance as Omega said. Still true after all these years. And unless you come up with some big dyno numbers, the whp has NOT changed a lot at all on s/c motors over all these years.

Soon......

Time is of the essence young grasshopper

Arm because I am not happy with your comment that Omega stuff is out of date, read what he said and tell me what to find fault with. Go ahead, make my day.... and trip over your fingers when you find he is saying in part what you have been saying. Which means you must be out of date? lol

Tyler Omega5 Maidstone SK redline Forums.

Before going into too much detail, there are a few things about SC'd engines that you need to know.
1) Higher exhaust flow in an SC'd will yield more power. That can be achieved in three ways; higher port flow, higher valve lift, or longer lobe duration.
2) The power delivery of the combustion cycle actually happens later than in a turbo or NA engine. Opening the exhaust valve too soon, can actually hurt performance, as a majority of the energy is being lost out the exhaust.
3) .... I won't go into that now.... it's a camshaft thing.

With that said; we know that a longer duration can potentially hurt performance. Therefore we should achieve maximum exhaust flow via higher lift and higher port flow.

It has been shown in the past (with other SC'd engines) that the ideal exhaust flow (rule of thumb) should be ~80% of the intake flow... for higher boosted engines, that can be upward of 85%. It has also been shown that to get the optimal exhaust flow ratio, it can be beneficial to sacrifice intake flow.
Of course there are various factors that come into play when finding the optimal port flow, so don't take the above numbers to heart.

Now... I know that some people call BS on the I/E ratio stuff.... however think of it like this; what goes in, must come out. Properly balancing your intake and exhaust is very critical

everything I have read states that a sc engine likes a port with lots of volume a tad on the lazy side due to the fact a sc engine will make the spent gasses go out of the port but you can over gut a head a snail prefers a high velocity port with a lot less volime for spooling reasons

Running the B207R cams on my M62 set-up I believe strongly hurt power. There is far too much duration and a shit-ton of overlap... No good. Will find out what the power gain is swapping back to LSJ cams in about a month here.

Anyone have good tips for getting the motor low enough to get the balancing shafts out
Trying to get around lowering the cradle

I was thinking the same thing, I hear it can be done, its just a big PITA

That's all I was trying to say. I'm going back over some of the things I've read in the past and pulling them together. No point on arguing without the info I'm siting linked.
And no it's not just forum posts. Real info from people in the field.

the cradle either has to be dropped, or a hoist used to pull the engine up to clear. No way around it theyre too long to snake out. And lower the cradle is gravy u dont even take all the bolts out and just let her hang

I am not sure what you are referring to. Real info from people in the field? Your good buddy John says " you can overgut the head" .

and GMR? You think for a nanosecond, they would have NOT produced a head that made the gains needed, for sale?
This after their countless hours dyno testing, Bill Duncan (who you may have met at the CED meets, this man is a real expert) was responsible in just one instance, of developing a time attack supercharged engine back in 2005, with enough budget ( more than any of us for sure) and some time ( at least six months for the particular project) considerable resources ( they made, and developed and sell the engine/car) . Their conclusion? Port the exhaust, leave the inlet alone.

Is it possible that porting the inlet as well would provide gains, if the exhaust was ported to the degree that additional inlet flow would be desirable? Perhaps. But I doubt any of you, and Arm you are in that group, have a superflow bench to measure the flow, and the access to a repeatable result in a climate controlled dyno, to measure the power results. So its a guess.

Which leaves me using a GMR head ( nothing to worry about, stick it on and forget it) or folks, for example, using a Euthanasia head copy of a GMR ( he has been porting for over 15 years, so probably knows how to do it without hurting it) and then seeing where they end up.

I am satisfied with 300 whp. plus or minus. depending on octane. I wont use race gas anymore it costs too much, so its 93/94 octane up here.

I cant see the need for any more, like Mr. B says, the dyno sheets posted are for bragging rights. If I do want to spin my wheels more, I can go buy an LNF.

In the meantime, thanks to Tyler for a good analysis on RLF, and GM for selling a real good head ( no longer available) and Euthanasia and guys like that who have copied it.

Good luck with the project Arm, lets see it finished!

Piston rings, bolts/gaskets, and machine work are left.

Like I said, soon....

Do I have to remove anything else out just drop her down

you don't need to remove the cradle to get the balance shafts out remove the trans mounts and loosen the cradle bolts as much as needed take the passenger side mount out lower as much as needed

I can agree with some of what your saying I think the gmr head is plenty but once you get to to where your moving a lot more air then the gmr ex port will become a bottle neck and more port is needed

Thanks mr.b

what john said. Obviously the timing cover, balancer etc. It was actually very easy did it in my driveway in a bout and hour and a half (when i said dropped i meant lowered, not completely removed)

For it's time i think the gmr was a great head, we've taken the lsj to another level with small pulley tvs cars.
Gm, made their goals, so why go further.
If you can move the air in, you're going to need to get it out. Infra's head was huge before he had it blended in, I saw first hand how large it was, and I'm sure it was opened upo even more to even it out.
His dyno graph proves that the larger port made a difference,
That same head was on Mrb's m62 car and did poorly, picked up 20 hp from a gmr size port we did.
But at that time his 2.8 m62 just wasn't enough to take advantage of it.

Maybe my new blower will take advantage of it....

;)


Only 2 people know what it is. Should arrive this week. And no I'm not telling what it is.

Yet.

(Hint: no one has put this on an lsj yet)

Are all the guide bolts the same length for the cam drive

Pulling my old head off and the bolt for the stationary front guide (one you remove the 8mm plug to get to)
Sheared off

Good luck with the new blower Arm I am waiting to hear how it all works. And for the folks who think that GM only worked with the tools they had, and now there is new info out there, figure this:
they had TVS.
They had unlimited pulley sizes,even sizes I would be shy to put on a blower and required machining the snout to fit.
They had huge resources, so much "pull" that they got Eaton to make TVS screws for the M62 that when Joe Public calls Eaton for the same screws, Eaton say " get lost".
The made cams ( the GMR 272 were released) to test.
etc.

Eventually GM's tools and the desire to mod the S/C evaporated as they were on to the next great thing.
But to think that over the course of time, principles change and we can all do better? It is entirely possible that Arm will do better. But we will have to wait and see. Re inventing the wheel is tough for an indie guy like Arm. We all wish him well.

no they are not. get the correct bolt. They break , ask Mr. B.:guns: ZZP talked of upping the size to 8 mm.

Have fun getting that bolt out. I had the rear guide pivot bolt break and it was very .......well not so fun.

Do you have a thread length in mm

I have a spare motor but the previous owner gave me a large bag of hardware Lmao

I'm not worried about getting it out and retapping it because I have a cnc ported head going on when I get home tonight