308 carb airbox restriction discovered

Russ, note the height of the box -- it looks at least an inch taller than stock. As I said above stock air horns were used, so there's a lot more clearance inside the box.

 

Here are two 1978 308 GTS's in this group. One is bone stock and unmodified including an operational air pump the other is the 308 modified as discussed in this thread.

Like I said earlier. Short stacks are nothing new and it isn't voo doo engineering. Pierce Manifolds has them for Weber 45 DCOE's.

It seems to me that I could spend 1,000 USD on dyno trying out all of the incremental changes in the quest for the holy grail of 308 mods and there will still be contention and dispute regardless of the resulting stack of dyno graphs. So why bother. My 308 runs better than it ever has, makes more horse power than it did last year. I did it for me, nobody else, I'm happy.

Here are the numbers from dyno day. Make your own conclusions.

1971 365 GTB/4 - 270/237
1978 308GTS - 184/163
1978 308 GTS- 162/146
1983 512BBi - 263/286
1984 308GTB QV- 187/156

2004 Maserati QP- 340/275
BMW M5 - 334/324

Viper w/nitrous- 596/633

 

Which one is the stock one?

 

DJ,
My Mondial should be running next week Kermit is trying to get the car scheduled for a DYNO run on a Saturday since weekdays is to busy for me to leave work, If you want we could get our cars dynoed together the same day.
Meridian is charging us $70-$75 for an hour, as many pulls we want in 1 hour.

Randy

 

Thanks for the heads up Randy.
I wanted to stick with the same dyno I've used for the last two sessions to make sure I wasn't adding yet another "deviation" into the testing process. Different dynos can produce different results.

 

Dude,

You don't need anymore "deviations" -

viva enzo

 

ROFL!

 

I should clarify one thing about my "opinion" on the short stacks. I think that there is a problem with the clearance of the stock stacks and top of the airbox. And, the short stacks relieves this, but, has anyone considered somehow raising the top of the lid for more clearance? From a totally unscientific point of view, I've always seen tall stacks on race engines and theoretically I'd hate to lose some low end even if I were to gain on the top end.

Just some ramblings.

Henry

 

Spasso,
You just hit a very valuable point right on the head, and it has not been pointed out before.
Each dyno is pretty much identical, especiially in MFG's models. BUT the location can have a distinct effect the outcome.
ALTITUDE, for example can have the biggest part in the equasion. Air density, as it relates to height above sea level will give very different readings on the same car. Reason: a quart jar full of less dense air will naturlly contain less Oxygen molecules than a denser one. Simple physics. And as we know it is Oxy that gives the "F" in fire.
Something as simple as moisture content can make a significant differance as well. The more "water" in the incoming charge, as it is by nature Oxy and Hydrogen, WILL burn differently as it gives off it's molecules upon combustion.
Some food for thought along that line: Nitro is added to Methonal to make Nitro Methane (Top Fuel). The reason? it contains a lot more OXY in it's molecular chain than air, a bunch more, and that is released in combustion! TF typically runs as much Nitro in the mix as they are allowed to, for just that reason.
The Dyno that we use is the same one Alex uses, but would no doubt be a few HP different in final readings, as explained above.
It is my understanding that this model records ambient air conditions on each run, and saves them. The next time that the car is strapped down, be it a few days or a year, it calculates the effect of any differances in the funal printout, so it is as though the car never left the rollers, (note the numbered run part of the printout).
As to Randy's offer, come on up and play! The more the merrier!
If you decide to, and don't make ANY changes in the meantime, that should help give an idea on the differances in location. which could benefit us all.
I have BTW, a set of Weber jet gauges (plug style) and reams if an on the spot opening up of a jet is necessary, or wanted.
Disclaimer: This post is not intended to promote sales in any way shape or form, but is intended to exchange information, for the good of all.
Then again, maybe you , me and Russ could start a 12th step Dyno Group, LOL!
Kermit

 

Henry,
I am sure somebody has thought of raising the box lid but before they did they placed a piece of modeling clay on top of the box and closed the hatch, later finding the clay squashed flat upon raising the hatch.

 

1. See the dyno numbers of the two 1978 308 GTS's. You don't see anything meaningful?

2. "Otherwise well engineered Ferrari?" First rule, Just because Ferrari designed it doesn't mean it is the best design. Too many examples across the product line to list here.
The emission control system that was forced on the 1978 308 was a series of desparate compromises to bring the car into compliance with US Federal Emission Requirements. The result? A loss of 40 HP. I see nothing well-engineered about that. The subsequent injected 308 was worse.

3. Finding and removing a factory designed and installed obstruction in the induction system isn't seat-of-the-pants as much as simple logic. The engine needs air to run. The more the better. Once the available supply is increased then the fuel delivery can be increased to take advantage of the plentiful air supply. The result MORE POWER!. Not IF but MORE.

4. Item #3 three has been utilized by mechanics since the inception of the gasoline engine. No dynos. No computers. No engineering degrees. No charts, graphs or 8 X 10 color glossy's with circles and arrows. Just plain old common sense.

 

Maybe we shoud do like the X1/9 guys do and put a big scoop on the engine cover that pokes up above the cockpit. Now we'd be talking some ram air...

 

I own the other car that that Spasso's comparing to. Not only did his numbers improve over last year's run, they show a drastic improvement over my car in it's well tuned yet: stock air pump, cats, dual points, airbox, etc. We have the same year US car, ran on the dyno same day...although the dyno has atmospheric logic...etc.

I wanted to snap shot my car's hp before changes occur...compensating for driveline losses, my car's basically at the US spec of 205 hp. I don't believe the mods to the US market cars were well engineered at all. In fact, in the long run, the smog system does great harm to the engine, particularly the exhaust valve seats...too much phuquein heat! Can't wait to see it all go away! PeterB.

 

Fourcam,

If you haven’t noticed this thread is only for people that agree with Spasso if you post a anything that questions Spasso’s opinions and statements then he and a few others will heckle for daring to ask for facts that are not masks as opinions.

Russ started this thread started out about how to remove insulations restrictions in the snorkel and airbox, the removal of restrictions in the air feed setup without argument is one of the best things you can do to make an engine breath and any engineer will agree. Give the airbox all the air you can!

However the thread moved to the low profile stacks and great claims of HP gains, yet when questioned and getting past the flames of who hates who we found out that the HP gains could not be attributable to anyone item or change. In fact Spasso admitted that these were only his opinions (in regards to his Dyno Run) as he had made so many changes in his setup.

“Paul,
You are correct. I did not dyno between each modification as would be warranted in a true control experiment and no, it is not possible to determine which modification made what percentage of the horse power to the "Nth" degree.” (by Spasso)

Actually Spasso….to any degree!

I now have some additional questions for Spasso (you may answer with Bold Capitals and Red Lettering as this seems to make you feel more in control):

The Following is your from your earlier post:

“As far as Stewarts car having an inconsistant baseline, baloney. Unless an engine is going through the throws of self destruction, the ignition system is self destructing (which it isn't, Electromotive), or the fuel system is malfunctioning (which would be obvious to the dyno operator) it should post fairly consistant numbers within 5% over and over and over, changes occuring as the engine and vital fluids get hotter and hotter. Unless somebody starts turning screws and changing timing it will do it over and over and over.” (by Spasso)

Let me get this straight; the dyno results could vary by 5% between runs as the engine and vital fluids get hotter and hotter so then answer this: based on YOUR statement on your dyno runs you could have had a 9.4 hp increase in HP due to nothing more than the 5% variation you claim can happen (9.4 hp = 5% of the 188 rwhp) with engine temp increases. So maybe all those changes you did actually did nothing…..simple logic based on your data and opinions.

These are your words not mine so leave please try not to attack.

Lets move on to the next item as in this case I believe you are messing with a design that was put into place with some substantial engineering that you know nothing about.

You talk about the fact that the idea of the short stack cures a “problem” because the factory stack tops sit so close to the top of the airbox and therefore that creates a “restriction” of airflow. Here are the problems with this backyard engineering (my opinion).

You base this restriction theory on a static basis which only shows at idle that airflow may be restricted (the car is not moving and thus the engine is searching for air) at 8500 rpm’s in 5th gear the car would be traveling at a speed in excess of 140 mph’s and thus the airbox would actually be somewhat pressurized (for lack of a better term) and your imaginary restrictions would cease to exist. There is no doubt that especially with the insulation removed that at speed you are supply enough CFM’s for the car to breath, the second snorkel would assist only in a low speed situations that are more prevalent in rally car design or a engine with a much larger displacement.

Next you have removed the factory velocity stacks without taking in to consideration that velocity stacks are fundamental part of the total length of the intake runner as a hole (yes it is upstream but the formula for design considers the stack as part of the total runner). When messing (REDUCING) the overall runner length you are setting yourself up for problem in the real world as you now are going to start dealing with REVERSION as the RPM’s increase and valve overlap because more of an issue. Basically you have now screwed with the pulses that are what the intake stream is all about (most think that carb airflow is a steady stream, it is not even close) and the ability for the carb and overall runner to absorb the effects of reversion.

The only way to increase the volume of air available is NOT to mess with intake runner engineering by shortening the overall length but to increase the size of the overall airbox or increase flow into the box. This thread seems to imply that Ferrari Engineers in an afterthought made the stacks fit the airbox for the sake of fitting the airbox when I have no doubt that the intake system was a well engineer package that took in consideration valve overlap (at higher rpm’s) and the pulse spacing that would be needed to be dealt with. The insulation was most likely an issue of sound (occupants comfort) that did negate some of the engineering but that comes with having to sell the automobile (compromises). And yes the latter is my assumption. In the end it’s all about volumetric efficiency (VE) and you’re not even close to being able to substantiate and increase in VE at idle or at speed.

Your claim that Pierce sells shorty type stacks somehow justifies this product simply doesn’t fly as a short stack may work fine with car whose overall intake runner length takes the short stack length into it’s design consideration or a engine that is designed for a particular RPM range of performance. But that must be done with some engineering and there was none of that here.

Simply put this short stack concept is nothing more than snake oil (no matter who made it) and it has no basis is engineering (Voodoo engineering? yes) and ZERO FACTUAL DATA to support the claims being made in this thread. Remember split fire plugs they didn’t do what they said they would (create HP) but they didn’t harm anything, what you are promoting creates real world changes that you know nothing about and may ultimately do the reverse of what you are promoting. You have changed intake runner length for possibly only a static HP gain. God only knows how lean the car will run at speed in the real world or for that matter how rich it will run with your jetting changes.

You may make a 1000hp on a dyno but it is static and front-end intake airflow modifications are anything but static!

You’re right this is not rocket science but it is a science.

Now feel free to attack me for issues outside of what I have posted here, as you really seem to not like the questioning of you position and your opinions. Just remember I did not challenge your facts or engineering …. As you have zero.

Paul

Photo below taken (by me) Friday at Sebring: Prodrive built 550 Maranello (6 liter) FIA Championship winner Europe 2004 season. The chief engineer seemed very interested in switching to those short stacks after I mentioned them to him. We both agreed that these were much to long.
Image Unavailable, Please Login

 

I propose that now that we've had a thread made for Sloan to ***** about anything related to Kermit that now we have a thread dedicated to people *****ing at him for being so incessantly combative.

But just a few points... There's a lot of poor engineering in these cars. Why can't the air intake system (with or without sound deadening) be part of it?
FYI, I drive my car at 6000 RPM in first gear, not fifth. So I don't have 140mph ram air. Maybe I still have restricted breathing, huh? As for your insistence on keeping the intake tract of stock length, a shorter intake tract benefits a higher tuned RPM. So if I want to tune the car to higher RPM why wouldn't I? In this case, there may be another reason; I know you dispute the dyno data that's been run, so be it. Just don't inist that this is "a well engineer[sic] package", because I don't automatically assume that anything on this car is well engineered, and I can assure you that the air intake system is a commonly compromised design. blah blah blah good nite.

 

Sorry Paul, Your quote is not accurate (like most of your quotes and arguments)

I explained (in a private email) that during my dyno pull LAST YEAR that the HP on my car started at about 173 HP on the first pull and stopped at 176.5 HP on the third pull due to what I believe was a rise in oil and gearbox temps thus lowering viscosity and reducing drag. The car wasn't fully warmed up when I started.
The difference being about 3 HP NOT the 9 that you think I said. The 9 HP gain was between last year and this year so your math is based on a faulty premise.

The test last year was before ANY of the current modifications were made. The experience of thousands of tuners over the last 50 years may have something to do with the changes that were made.
Not that it will make any difference because you will select any statements made to suit your argument and twist the rest.


As far as the 5% figure goes, I could be wrong. I threw that number out there as a "working number", not an irrefutable, scientifically supported fact like all of your numbers and opinions. It could be 2% but if the 5% number helps your argument I am sure you'll continue to use it, right or wrong.

You have absolutely no idea what my knowledge and experience is as you postulate about my "backyard" engineering and "imaginary" restrictions.

What ever you say Paul. You're the man. How could anyone IN THEIR RIGHT MIND argue with your perceptive and expert analysis, even though none of your "opinions" are backed up with any hard evidence or scientific proof (ZERO FACTUAL DATA).

You win. I am wrong. My 308 didn't make any extra power this year that was attributed to the short stacks, even though you have absolutely no case to prove otherwise.

This must mean that Russ's Mondial didn't benefit from them either. But who are we to argue, we only own and drive the cars while you analyze them from behind a computer. Egads! You must know more than we do about our own cars.

Your logic is indisputable.

You have the last and final word. You win. You can feel good with the knowledge that you "beat me".
I rest my case.

DJ
1978 308 GTS
184.6 "imaginary/unscientific" horse power
163 "imaginary/unscientific" ft lbs torque

 

Spasso,

My quote of your statement is the surrounded by quotations and is a cut and paste from your post it is unchanged in any fashions including all the grammatical errors. Adding my separate paragraph as if it where your quote does change it but you did that, not me. Your private e-mail answers nothing it was just a back tracking of your public post. You change your position so often that I can’t keep up. It's 5% now its 2% well at least you still have 1, 3 and 4% to go to.

“You have absolutely no idea what my knowledge and experience is as you postulate about my "backyard" engineering and "imaginary" restrictions.” (by spasso). Then address the issues I have raised! You are the voice behind this thread yet you refuse to substantiate your position with anything but attacks,silly responses and changes to your previous statements .

You have avoided the issue by simply attacking me, now answer the questions and show us how the change in overall intake runner length does anything more screw up the engine dynamics in the real world. You are messing with stuff and promoting changes that have consequences far beyond your knowledge. It’s simply snake oil once you get past opening the snorkel.

Don,

As for Don all I can say is thank you for attacking me for issues that have nothing to do with this post but if you read my post you can say I expected it from those that can’t handle the questioning that challenges the promoters.
Your "full name" in your personal profile seems to explain the level of what I am dealing with here "Full Name: Mr. Jablowme"..... now that's impressive!

I wrote my post so that those who might believe that these changes may be harmless and to show that those promoting them have no knowledge in what they are doing (outside of the snorkel restrictions).

SHORTENING OVERALL INTAKE RUNNER LEGNTH IS NOT SOMETHING ANYONE SHOULD DO WITHOUT TRUE KNOWLEDGE OF ITS OVERALL EFFECTS ON THE ENGINE. PROMOTING SUCH CHANGES WITHOUT KNOWLEDGE OF THE CONSEQUENCES is irresponsible.

Paul

 

Whatever, dude.
Spasso was right to declare you right. You're both right. Except that for you to be right he has to be wrong. But I'm sure that in the end it just means that I was wrong. And perhaps Spasso, too.

Haywood

P.S.-what do you think about changing plenum volume on engines? Oh, never mind... LOL!
P.P.S.-thanks for EDITING YOUR POST to make fun of my name, I've only gone through therapy for about 26 years about it.

 

Mr. Jablowme (his full name)

Try sticking to the issue of shortening the overall intake runner and then testing it under static conditions with several other changes. Respond to the ability of a shorter intake runner to handle reversion at higher rpm's and asorb it effects.

Come on deal with the issues hell I may be wrong but until you can answer the legitimate issues with some facts and data or at least some enginnering that doesn't come from Spasso "backyard" we will never know.

And please leave people out of this that have nothing to do with it, it doesn't change the real issue here....the lack of engineering and the promotion of gimmicks.

Paul

PS. And now I will have go to through therapy for your attacks on me. Guess we are even?

 

Some of you may recall that there were to threads on this topic before.
There was posted the FIRST Dyno sheet that entailed JUST the test of the LPHF horns.
This was done by :
1. A baseline test with the stock air horns in place.
2. while still on the Rollers, the new style was then installed and NO other changes were made.
3. Several runs were made to warm the motor to the same temperature as the baseline, prior to the test of the new units, so that the test would be as valid as possible.
The resulting pass made showed a 4.4 HP increase in HP in spite of the fact the motor LEANED out .2 with them in place, indicating more air WAS getting thru. While I do not have the formula to calculate the differance .2 leaner (from 13.2 to 13.4 to 1) I would think that this is certainly indicitive that it is reasonable to believe that a 5 HP increase wold have been possible had jetting been available.
On the topic of shortening the effective runner length, it is common knowledge the effect this has on power bands. HOWEVER, the differance in length is minimal, and the power band did not move noticably during any of the tests, including the later ones with the sound deadener removed.
"Backyard". I think not.
GIMMICK? the dyno sheet proves more power.
Now could we move on with an intellegent discussion, of a technical nature, without the rantings?
Perhaps a side note on the effects of resonant pulses might be more intellegent.
I would note here that I made this post, NOT to allude to or promote sales in any way, but to defend myself.
Kermit

 

Sorry to have opened up the can of worms (again).

Thanks again to Russ, DJ, and others who have provided worthy technical info. Ultimately, everyone must make up their own minds on what works best for them.

Henry

 

snj5, good stuff on resonance, but what about intake anti-reversionary it all has to be related? This has always been an unanswered question for me. If the intake which works off of sound waves (pulses) also works on exaust, what then are the dynamics of intake pulses? Sure the pulse goes from valve to intake trumpet, but is that the end or does the pulse continue into the air plenum but in a reduced state. If it does continue then plenum anti-reversionary design will enhance inward flow or signal. If you look at the flowmaster muffler it works on the principle of canceling return pulses (anti-reversionary) actually blocks return signals and produces more flow than a straight pipe. Shouldn't it make sense then that the same dynamics would or could be at work on the intake side, bearing in mind that this would be independent of runner length.

Best regards

Gary