How much power is a ported stock intake worth???

I realize that's a loaded question without some detail, so here's the detail below!

Jim Weise finished up my motor for my GSX and it's currently enroute to me! Awesome!

It's basically his Level I motor with the following exceptions:
-Stock intake instead of port matched and cleaned up Edelbrock
-The heads are Gessler ported Stage 1 pieces instead of Trishield ported small valve pieces
-The carb was set-up by John Osborne
-IgnitionMan curved mag pick-up distributor connected to MSD box

Did I miss anything Jim??

The Level I motor would normally yield around 460 HP and 540 ft-lbs of torque. My motor, as noted above, yielded 424 HP and 500 ft-lbs torque through headers and 408 HP and 475 ft-lbs torque through exhaust manifolds. That's somewhat lower than what we both expected. Respectable numbers, but a little less than anticipated.

Jim thinks it's probably related to the interface between the big valve ported heads and the stock intake. I'm sure he'll chime in here, but his measurements of volumetric efficiency (I think that's the right term) showed some loss over a more well matched combo. Jim also told me that the carb was set a bit lean, so we're not sure what might have been gained in richening it up.

Now in all fairness, the motor build didn't start out as a Trishield event. I had already procured the heads and sent them to Greg for port work. The IgnitionMan distributor was already in hand and curved for the motor in stock '71 non-stage trim. It was only after talking to Jim to seek advice on doing this build up right that the idea of Trishield putting the package together came up. The result is I asked Jim to put together a combination that wasn't one of his tried and true. It's a combination that I pieced together, but one that on paper (at least in my head) would work. Perhaps with a bit more dyno time, Jim could have gotten more squeezed out of it.

My question to you guys is with regard to the loss through the stock unported intake that dumps into generously ported heads. Jim thinks there may be a slowing of the mix (velocity issues) and resulting turbulence. That makes sense to me. I'm curious as to what peoples experiences are with a similar set-up and what cost/benefit might be there in having the intake port matched? I do have time before this motor goes into the car and am looking for input as to whether or not it would be worth putting any money into the intake. This will need to look bone-stock, so aftermarket intakes are not an option. Naturally, if the benefit isn't there I don't want to throw away good money.

I'd appreciate any opinions.

Thanks Guys! :beer

 

Yeah, Larry, but will he have to kill me after he tells me???? :eek2: :laugh:

 

I'm no expert, but looking at the drop when using exhaust manifolds you may get bigger bang for the buck by using Greg's magic on the exhust manifolds to make them flow better. Or do both the intake and exhaust manifolds!

- Bill

 

Ken, one thing Jim Burek found with my motor is the intake can't provide enough air for the heads. I believe the runners aren't large enough with my intake ported, let alone an unported one. If you want to keep it looking stock I would port the iron one out to help with the air delivery. I believe that has to be one of the biggest drawbacks keeping you from getting more horsepower. Also, look into porting the exhaust manifolds out too. The only way I can get to the 600 horsepower mark on my 350 is to get a custom sheetmetal intake built. None of the current intake manifolds available for the SBB can provide the amount of air my heads require.

 

What about taking a Performer intake, having the Edelbrock ground off and porting that? Those are pretty close to stock.

 

Thanks for the responses so far, guys. Larry, all kidding aside, I need to see what Greg has to say. If he doesn't weigh in here, I'll email him and ask his opinion. Bill, I'd consider the exhaust manifolds too, but not sure if the meet the bang-for-the-buck requirement. I recall seeing a thread here recently where Trishield did a baseline to ported manifolds to TA shorties to TA ful length headers. It seems the ported manifolds did offer some definite advantage, although no matter what magic Greg does they would have trouble keeping up with the scavenging of a well designed header.

Rob, although you have a small block, I would think the same rules of physics would apply; it being a matter of to what extent. Obviously, the breathing your small block is doing greatly exceeds my big block! :eek2:

Below is one of the many pics Jim sent to me of the engine build up. He notes that the size of the intake ports on the heads are much much bigger than the intake. Sounds like quick moving air being dumped in a large volume and losing speed???

Thanks again for the replies!!!!

 

Phil-

I'm thinking my car is heading to concours, so I'm looking to keep stock casting numbers. I appreciate the thought. I should have said how I intend to set my car up. I'm not looking to make it an all out race car, just a fun car. If I can squeeze a little more out, I'd be interested in doing it. But I'm looking for a decent idle, plenty of vaccum etc. I'm not saying the Edelbrock will negatively affect idle, vacuum, etc, just elaborating on what my intentions are.

Sorry I didn't specify earlier. All part of that is it worth it to do any more equation.

Thanks!

 

a little background..

First off, let's discuss Ken's motor.

In the testing, no attempt was made to make it a "dyno star". Since we know it's going to be a concours deal, and carb spacers are not in that equation, we did not even try one. I think a 4 hole 1" spacer may have picked the motor up considerably, but you can't plunk one of them on a concours show car. So the carb was left alone, sitting right on top of the intake, and it has the typical fuel curves that John Osborne puts in them, which are a little lean on the dyno, but in the car, work good. It won't be lean in the car, since it's going to be hooked to a 2 1/4 or 2 1/2 inch exhaust system, instead of the 8" exhaust system the dyno has.

All we were after is the representative numbers that the motor will have, as installed in the car.

Now, in relation to it's output, there are a few points to be considered. The only other motor I have tested with stock intake and exhaust manifolds, was a 70 455 supplied to me, to put in a car (74 GSX) by a customer. That motor was stock, no head porting, no zero deck, and with just a 113 cam, and then tested with our level 1 cam. With the 113 cam, and as well as I can recall the numbers, I believe it made about 370 HP and 450 torque. It was a few HP stronger with the Level 1 cam, but the point of replaceing the 113 was idle quality issues, and we did acheive that with the Level 1 cam.

So Ken's motor, with it's zero deck height, and ported heads, is considerably stronger, than an otherwise identical earlier tested motor.

Also, a lot of "stock rebuild" motors of various makes have been tested on this dyno, and they never come up to what the factory rated them at, with all the stock manifolds in place. Ron swears it's because the manufacturers used headers on the motor when they tested them. Apparently one of his friends was a vendor rep back in the day, and was in the dyno cells, and observed the motors of many different makes, with headers on them for testing. I am going to have to call Denny and clear that up, with our Buicks.

Now, I have tested Greg's ported exhaust manifolds on much more potent aluminum head deals, and they have not shown a tremendous increase in power.. we are talking a couple HP here.. But, with a motor like this, they may in fact show a more appreciable gain. Combination is important here, and there are very few guys out there (if any) doing serious R&D work, playing around with just cam changes and some intake, head, and exhaust manifold porting on an otherwise stock engine.

There is a good reason I don't offer a "resto HP combo", because I have never had anyone who is interested in investing in the development costs. I personally did (and paid for) the development on the Level 1-4 motors, because I knew there where going to be a lot of folks interested in those types of engines, and it was a wise investment. But the restoration stuff is typically part of a very expensive car project, and those customers are generally more interested in a mechanically sound engine, that produces the power it did from the factory. Certainly they are not opposed to slipping a little hotter cam in, but we are talking about a developement program that would encompass muliple dyno sessions, cam changes, levels of porting work ect.. and that's not an inexpensive process.

How much would Ken's motor pick up from intake and exhaust porting?.. my guess, based on previous work with stock stuff on much more potent builds, would be in the 10-15 HP range. But, unless we test, that is just an educated guess. The motor may want different cam timing to compliment the package.

The long and the short of it is that I have to have someone willing to invest in the development process, then we can all benefit from the experience. So if your willing, we are able.. But if I was footing the bill on a total resto, I prolly would not be spending a lot of money on engine development, since there is so many other places that money can be put to wiser use.. So I certainly don't fault Ken(and everyone else) for not wanting to have a 10K 425 HP motor..

Here is a pic of Ken's motor, on the less than a year old Superflow 902 dyno, which is a very nice, and accurate piece of equiptment. I would speculate that this is much more accurate than the same piece of equipment, in use 35 years ago. This alone may account for some of the confusion between "stock" motors, and fresh builds that are warmed up a little and then tested on 21st century equipment, and then compared to stuff built and tested 35 years ago.

JW

 

I would like to note that my posting of the question regarding intake porting was not intended to take anything away from the wonderful work Jim did on my motor. I don't believe I came across that way, but I want to make sure my meaning was not misconstrued. I'm a fan of Jim Weise!

I know I will be getting a motor that is well put together, well thought out, detailed, and done right. Anything I could put together (or have put together locally) would not have the same durability built into it. That is first and foremost what I am looking for for a '71 GSX. The peace of mind of knowing the motor show never give me a lick of a problem.

That is what I was after, that is what I got.

Thanks, Jim.

 

has anybody tried removing the divider on a stock intake? A local guy tried that a long time ago and claimed to have good results. Of course they were even better after adding a spacer. For a concours I would think anything you could do to add plenum volume might help.

 

No, I don't think anyone is taking it that way Ken.. I certainly didn't..

My personal goal for you motor was 425HP, with the stock manifolds, but it looks like that may be a little out of reach, without rolling up our sleeves a little more.

After all, the stock motor with a little more compression than yours, no porting, and a smaller cam, did put out 376HP.. and I am assuming that is with the exhaust manifolds.

That means we picked up 32 Hp, in the stock RPM range (5100 rpm). And the jury is still out on the torque..

I will be testing a dead stock resto 70 STG 1 motor, with an NOS STG 1 cam, later this spring.. we were not going to dyno this motor, but I think I will invest a little of my own coin in doing it, as I want to see one of these stock motors make 510 torque, at 2800rpm.

I can say right now, I will be surprised to actually see that, on the modern, computerized testing equipment.

JW

 

Yes, and on a motor that has some serious head flow, a ported intake, and headers, that is a good thing.. you generally trade 10 or so ftlbs or torque, for 10 HP up top. Did it on a 515 HP 455.

Also on that same motor, a dead stock, untouched, 70 455 intake made 495 HP, while the port matched performer made 502, and the Port matched performer with the divider milled down made 515.

Assuming that power increase with the manifolds is a percentage based deal is tricky at best.. just because a port match picks up 10 HP on a 500 HP motor, does not mean it will do that on a 400 HP one.. it may be more, or it very well may be less..

That's the real value of dyno testing and development, because once it's done, it's a guide for advising my customers.. and I can tell you a whole lot about what's worth it, and what's not, on 475-800+ HP motors, but this more stock stuff is still being worked out around here.

The truely dead stock motor I will test later this spring will be interesting.

JW

 

Hey Ken Good luck with new motor did you get flow #'s on your heads?

 

Can we defray R&D costs across the Buick Community?

Jim,
I'm a car-lover on a tight budget, probably like many on this board. I love reading the technical aspects brought in by professionals such as yourself "free of charge" to the rest of us solely for the benefit of our community. This is one of the reasons I'm building a Buick right now. To all who contribute, I thank you. My 455 build up was directly influenced by many on this board.
I understand R&D is expensive if everything goes as planned. Can we, as a community, help defray some of the costs for the R&D that will benefit us all? What if some of us we to "pitch in" so to speak to help with the costs? I'd be willing to send what I could to help out but I know I couldn't fully sponsor a project on my own.
So am I crazy or not seeing "the big picture." What do you guys think? o No:

 

i would gladly send 100.00 to help " the cause"

 

Sure..

If there was someone on here who wanted to build a motor, or has a current one that he wants worked on, I would not have a problem working out a program to do R&D work on that motor, using a pool of money from board members, with the results to be shared with the group here, for the benefit of all the members.

Such an effort would certainly benefit many members here. It can be as simple or as complex as the budget will allow ..i.e.. we could take a motor with the normal deck heights, in good mechanical condition, baseline dyno it, and then perform one modification at a time (deck heights, porting on intakes, heads, exhaust manifolds adding headers ect..) until the budget is exhausted.

What we would need would be an individual with a motor in good mechanical condition (a recent rebuild with quality parts or a good stock motor) and then a game plan on what we would want to try, and then a fund rasier to get the money in place.

I currently have a Level 1 iron motor, and a Level 1A aluminum head motor going together, and I can talk to those guys, and see if we can put something in motion. I will donate some time for the process, but the sublet machining operations, parts, and extra dyno time would have to be covered by the R&D fund.

Any of you guys interested in chipping in?

I think it would be best to take the Level 1 style motor, build it with the stock deck height and whatever compression the "normal" chamber sizes would allow, and then start custom tailoring it, one modification at a time and documenting it at each step, to be able to follow the progression of the motor.

I can, in a 4 hour session, test mulitiple manifolds (and I have most of them) and exhaust systems. I already have most of this info for the 1A type motor as I did some pretty extensive R&D on that motor.

This is an exciting concept, but remains to be see if we can, as a group, pull it off.

Good idea.

JW

 

Sure....Come up with a number...:TU:

 

I will talk to the guy I am building the iron level 1 motor for , and see if we can come up with a game plan.

JW

 

Hey, this is kind of exciting. I'm not used to having good ideas! I'm definitely in. Let us know what you're customer says!