It seems we have an engine done.

From what I did read on the board here, the TA Stage 1 might seems "unimpressive" when no kind of porting are done. In other words you can pretty much have iron heads that flows as much as TA's without too much efforts

 

Yikes Definitely a wake up.. I figured with the 2.77 GVFD your running about 18-1900 RPM at 50ish MPH. Mash the throttle up to 3000+ which comes up real fast. Trans drops into 2nd OD now your in 4.10 mode. That will send a car sideways.

 

Yeah, sounds fun .

 

BSFC. They are fairly high at over .500. Yet the AFR as measured by the turbine and fuel flow meter show a some what rich AFR, so BSFCs aren't high because it's lean. They are high because the motor is efficient at making power for the fuel it's given. I also noticed the fuel flows are rather low, I've been seeing 250 to 270 lb/hr on my motor so that's another indicator it's efficent.

 

Yep, that is certainly part of the equation Scott.

I had this one on the dyno again this morning, curiosity as to what it would make with exhaust manifolds got the best of me.

Let's see who can guess how much we lost with the the stock exhaust manifolds.

As a reminder, this one made 543 TQ and 456 HP with headers..

So while I crunch the numbers, and make and upload the video, let's take some guesses.

JW

 

I'm thinking the fairly small cam and smaller than usual I/E duration split and the tighter LSA caused the engine to pack a lot of wallop in before the heads caused a bottle neck. This "wrong" cam probably really liked the headers so down by 25 HP/35 TQ to 431/518.

Exhaust manifolds ported or really stock could make a difference.

 

I'm guessing he worked some magic on the distributor and we only lost 10 HP and 15 TQ by switching to manifolds.

It's like Christmas all over again.

 

I'll say 15 hp, 20 ft lb loss

 

My guess is after the switch hp wil be 440, tq will be 530

 

Ok guys, sorry for the delay getting back to you.. I put together the videos and graphs on new years eve, but it was late, and I like to do these lengthy posts in one shot... GF had me hopping yesterday with the "honey do" list.

So, first we some background on the manifolds vs headers swaps, it is a test I have done many times.

One note on reading dyno sheets... always throw out the first two numbers on the TQ/HP.. these numbers are influenced by how the machine runs the test.. it loads the motor at WOT at the start rpm for several seconds, this results in those numbers being a product of a "steady state" test, which will always read higher than the sweep test we are doing here.

Let's examine the engine that was in my 3/4 ton Suburban for about a decade.

70 Buick 455 SF 70K mile engine
Freshened with rings and bearings
Deck clearance .040
Actual compression ratio is 9.1-1
TA 212 cam= 218/230/112

Mildly cleaned up 70 Stage 1 heads (slight bowl port and chambers) - 75cc
Performer
800 Q-jet
TA 2012 headers and stock intake manifolds tested

This was not something I built from scratch for myself, I would have never left that much deck on it.. I got it in trade from a friend, after I put it together for him. But I figured it would be fine for my truck, and it was, it served me well till the fenders rusted off that thing. Towed many miles with my 26 ft enclosed trailer and customers show and race cars.

I picked this motor, because this is the classic "warmed over" 455 Buick. Freshened up nice oe shortblock, with a mild TA cam with the "conventional specs" and fluffed up heads.. one of his buddies worked on them with a cartridge roll in the bowls and chambers. Performer intake, Q-jet, HEI ...

Here are the numbers... first with manifolds

Superflow 901 dyno/300rpm/sec sweep test



And with headers..



Here's a graph of the two...



Averages are important to look at, not just peak numbers. I actually know this, but got caught on this latest test, telling Jon he would "be happy" from what I saw on the peak numbers.. but a more comprehensive look at the sheets on his motor showed it was not out of the ordinary.. but we will get to that later..

In this study, we are going to concentrate on Torque, since this is what the dyno really measures, HP is just a mathematical equation.. (HP= (Torque x rpm)/5252. High HP motors make and hold onto their torque at higher rpms. Great if your racing, not so much if your just cruising. You want high torque at moderate rpms for the average street car.. Dennis Manner said it best "You buy HP, you drive Torque".

Averages, 3000 to 4800 rpm

Torque, with headers- 459.8

Torque with Manifolds- 445.1

Headers add 14.7 ft lbs of torque, from 3000 to 4800 rpm

It should be noted that for some reason the header test was stopped at 4800rpm... so this shorter pull will show less average loss, because as you can see, the higher the rpm goes with manifolds, the more sharply the torque drops off..

This is a motor that the heads have been worked on...

For another example, let's look at a 430 I redid for a guy about 6 years ago..

Here's the specs

1967 430 Buick
.040 over
stock bottom end with rings/bearings/aftermarket cast pistons- 438ci
deck clearance .002
9.89-1 compression
TA 212 cam 218/230/112
1970 "786: Iron heads, standard valve sizes, mild chamber blend only
Performer intake
800 CFM Q-jet

I picked this one, because it has a full spectrum rpm pull for more data points.

With manifolds



With headers


Average Torque with exhaust manifolds - 478

Average Torque with Headers- 508

A full 30 Ft/lbs loss..

So that's two examples of headers vs manifolds with the "correct" 12* longer on the exhaust camshaft.

Now let's look at Jon's motor.

As we recall, it has a 226/227* cam in it, that he supplied..

Here are the header numbers from the second session..



And with the stock exhaust manifolds


And in graph form..



Average Torque with headers- 510 ft lbs

Average Torque with Manifolds 483 ft lbs.

Torque loss with manifolds - 27 ft lbs,

This testing indicates that in these basically stock engines, you will loose 3-6% of your torque, when you go away from the free flowing headers. Exhaust manifolds are backpressure devices, and the more air your putting thru the engine (making more power), the more toward that 6% you will be.

It also indicates that they really don't care about favoring the exhaust. Simply put, once you exceed the ability of the manifold to flow the gasses (and backpressure is developed) then opening the valve sooner, or keeping it open later, has no effect in increasing exhaust flow.

A concept I have actually held for some time.. My custom cams have rarely more than 4* split.

In this motor, the tighter 110 lobe center, that I installed only 1* advanced, positions the valve events for maximum cylinder pressure and minimum charge dilution. This produces a very efficient engine.

Ya know, While we would like to think that some labcoat types got together in a dyno cell, and smoked over a dozen different cam designs, when the first HP cams were developed for the BBB... I hate to break it to you, but that is not really what happened.. The Buick engineers, working with the stock engine and camshaft, realized gains when they increased the exhaust duration.. in that application, at that airflow level.

The first aftermarket guys saw this split, and it became "gospel" that you have to have considerably more exhaust.. and this is really a Buick thing, you won't see this anywhere near as much in other makes.

So, our conclusions are.. we pretty much got the drop from the exhaust change we expected, there was no huge drop off like I thought there might be.

This combo represent excellent power for the dollar. 450 HP with a good shortblock, stock heads, dual plane and headers is great power for the dollar spent.

Questions?

JW

 

Now, as I mentioned earlier, you have to be careful looking at numbers, and not averages or graphs...

I slipped a 1" 4 hole spacer under the Q-jet during the last session, just to see what it would do..

I saw a 44o HP number come up during the testing.. great, put it in my head that we only lost about 15 HP with the manifolds.. told Jon that "he would be happy" with what I came up with..

But a closer look, in graph form, shows that the numbers sometimes can fool you.. take a look



That's about as close as you can get, and the spacer only helps above 5000 rpm.. so there is no need to run it in the car..

JW

 

Q-jet air bell and air cleaner testing.

First off, here is how we use the dyno air bell, on a Q-jet..



Take the 5 1/8" neck adapter off the bell.. so it now has the dominator sizing, and then just tape it over the factory air cleaner. The base provides the proper airflow contour into the carb.

Always test... with this setup, and with the carb open..



The red lines are with the factory air cleaner base/air bell combo

They show a slight increase because we are now using shop air, from outside the dyno cel, which is a few degrees cooler..



That's a big duct, over the air bell. Feeding it with 70* air from outside the shop. Adds a little bit of power, but what your looking for here is some huge difference, because the air cleaner/air bell combo is screwing up the carb metering. I had one Q-jet, that lost 35HP with the air bell on.. we could not really explain it..

I also tested the 2" element, no drop base, with the filter top air cleaner assembly I have floating around the shop.



vs the carb wide open..


In this instance, both tests have the engine breather dyno cel air.. and the air cleaner actually was worth a couple hp.

As noted before, one would need to repeat this test in the car, with the hood over it to be sure.. but this test proves there is no carb issue going on with that air cleaner assembly.

Questions?

JW

 

WEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE! !!!!

Although my first reaction is, ouch, 30ftlb loss on manifolds. Those abandoned foot pounds are not worth the ridiculous efforts to force headers to work on a 67 A-body.
Who knows, maybe I will decide I just absolutely must get those 30 back, I reckon I could go long tubes but I don't think a street rod needs that.
This is a cruiser and tire fryer and will be perfect.
Thanks Jim.

I look forward to mid January when this beast arrives out in Oregon.

 

Check into the shorty header fit on that chassis.. they only give up about 1-2% over the long headers.

Not sure how they fit in a 67 with Stage 1 heads.

JW

 

Like an idiot, I went out to the car with the dummy block in there. I grabbed the shorty headers and it seems the passenger side will clear ok if I move, AGAIN, the brake line on that side.

Now the drivers side is a bitch. I think the big cast lugs on the heads will need to be sawn off to fit the shorty headers. I will need to drag the cherry picker back over there and raise up the drivers side of the engine and get that header on and see what happens.
Last time I did this, I thought my passenger side was a no go but perhaps that was back when I had the mount pads at the wrong positions.

 

Here's the updated movie..


JW

 

Jim, just need some clarification on a couple of items.

Exhaust manifiolds, factory stock or opened up at all?

When you say you like only 4* split I/E is that only for exhaust manifolds? Would you make the split greater for headers? Just looking for generalizations.

Since the manifolds become the bottleneck at some point would you recommend a wider LSA to keep reversion at bay if you wanted to rev higher(more HP) with manifolds?

Interesting thing about large exhaust spits is how the OEM is doing it on the LS engines. May have a lot to do with emissions though. Aftermarket is carrying it on although maybe not as great a split.

 

Mike,

Stock exhaust manifolds.. untouched.

I had the opportunity to dyno test both sets of ported manifolds that Greg Gessler used to do.. I think they were $300 and $500 pairs...

Results were disappointing.. increases of less than 10 numbers, for either set. The big dollar ones certainly looked sexy, but at the end of it, it's still a manifold, and still a backpressure device.

It's all about outlet size.. I suspect that the ones Rodgers is doing with bigger outlets would show more power gains, but have not had the opportunity to test them.

----------


That's for all cams.. I think the classic Buick thinking in relation to exhaust heavy cams, when applied to the performance aftermarket, is more folk lore than anything.. I have built some pretty impressive motors with a nearly straight pattern cam... there is alot of Monkey see- Monkey do in the cam business.

-------------------------------

No, spreading the valve events out has little effect on overall exhaust performance with manifolds.. for the same reason that altering/increasing exhaust valve timing does not really work.

I have done a lot of wide lobe center hyd rollers in the last 3-4 years.. and the tangible advantage to spreading the valve events out, is you can run a much more aggressive cam and still retain idle quality..

The issue with both altering the location and or length of the exhaust valve event is the inability of the manifolds to exit the gasses, without building backpressure. It's really a size thing, and that is whey they have been cutting the outlet paper thin, and now welding different outlet donuts on them, to increase the exit size. Think about headers with 3 or 3.5" collectors, and then what a manifold exit looks like.

Manifolds have their place in the performance scene, and I am always impressed with seeing a car run hard with them. But we need to be realistic about their capability, and how they are impacting overall engine output. One of the reasons that the newer engines these days do so well, is that they "manifolds" look like cast iron headers.

Speaking of that, I think if someone out there is looking for a project, there is a market for a good flowing header like cast iron exhaust manifold for our cars, that would be easier to install than shorty headers, yet provide similar performance. If one could produce and sell them for around $300 a pair.. it would be a huge success. Especially for the Stage 2 market, to give them a manifold option.

A lot of folks just don't like headers, and I understand why.. they are noisy, a pain to install, prone to rust, reduce ground clearance ect ect.. I think a cast iron header, where you might only loose 1-3% of your engine output, would be just the ticket for manifold lovers, and fed up header owners alike.

Just thinking out loud here on a Sunday Morning.

JW