WOW Bluegrass! I had never thought about doing that! That is a cool tip! So is 2 PSI the normal amount of Back Pressure applied and at what RPM is that? Is that completely stock or with an aftermarket exhaust? What is the normal PSI with forced aspitration? or does it change?

 

Wow, you guys really know your stuff. I sort of understand where you are coming from about moving the power band. I relate it to my motorcycle knowledge in racing that you can adjust the sprockets and chain which will place the horsepower, etc somewehere else in the power band.

Now with this expedition, I am not sure. I assume you mean the same thing. Moving the power to another area.

But I still don't get if its good or bad in my situiation in the last post I did.

I mean. The reason for doing this is to gain more gas mileage, have my motor work less so I get more life out of the motor, the sound is better than stock, and so on.

Now if I do it, only the muffler change and keeping on the K&N,

would it benefit my motors life, my gas mileage, etc? Sound I really don't care about. Just overall performance and benefits.

Also what disadvantages in terms of the car, and not my wallet .......

 

As we speed deep into engineering on this (yea right);
the point of optimun gearing for fuel mileage is one related to the weight of the vehicle, aerodynamics, rolling resistance etc vs the speed you want to manintain and the engine torque needed to maintain that speed.
The best gearing would be the ratio that allows the smallest average throttle opening.
Gearing to make the engine rpm too low, reduces torque available, causing the throttle to be opened farther, causing the consumption of more fuel to get the torque to maintain the speed. (As in tail chasing)
Gearing to low to make the engine rpm more than needed, results in lower road speed so the throttle needs to be opened further, "again" using more fuel to get the desired speed.
Gearing changes also changes the final torque multiplication to the wheels and is part of the results in addition the rotating ratio has on road speed vs engine rpm.
Of course the PCM adjusts spark to try to also help get the best fuel milage on the cars and trucks.
You have to think a bit outside the box as they say to see there is a best balance point to this subject for gearing.
One can observe that there tends to be a road speed range that results in the best average fuel economy, for these reasons.
Much of the above is why these trucks don't get the milage we would like. The weight is high, the torque is to low in the low rpm cruise range, to the point there is little throttle response without down shift--- there goes the mileage right out the tail pipe because the engines are on the small side as well as very conservitive PCM programming.

Are we "alcohol burning" and fool injected yet?

 

I personally currently run K&N in all of my vehicles though I am thinking about the new Air Hogs by Fram for the next one I buy. But It's simply a convience thing for me...The rechargable/reuseable so that I dont have to remember to pick one up every few months or so. I can just clean it and reinstall it. Leave your K&N in, it is fine.

 

For your exhuast...do you drive mostly city, mostly highway? Where do you want the performance? Do you want more in the launch, cruise speed, or in the top end? Everybodies set up is different...Most on here complain they dont have enough take off power and they peak in the top end.

 

Man Bluegrass I wish I could get everything in one post like that with out it messing up!

I have the opposite problem that everybody else complains of...10MPH or less I can not apply over 1/2 trhottle with out the tires breaking free. So I need less in the bottom and more on top so that I can utilize it all. It is not safe for me to floor it untill the truck is already doing atleast 20 mph then sometimes it will still break free. Wet pavement forget about it... they have broke free at 60 mph before on it. Since I want to move mine up I am going with as free flowing exhaust as I can find and or make and adding a set of yet undetermined larger ratio of Detroit lockers for my rear. Plus relocating my battery to under the bed and putting a fuel cell in the spare tire local to add more weight over the tiresp so that I can utilize it all. It is not safe for me to floor it untill the truck is already doing atleast 20 mph then sometimes it will still break free. Wet pavement forget about it... they have broke free at 60 mph before on it. Since I want to move mine up I am going with as free flowing exhaust as I can find and or make and adding a set of yet undetermined larger ratio of Detroit lockers for my rear. Plus relocating my battery to under the bed and putting a fuel cell in the spare tire local to add more weight over the tires. Later will add a fiberglass front end to shave a few 10ths off the 1/4 mile along with some other goodies.

Fuel injected yes...Alcohol.. ummm.. No, still pump gas I hope!!!
But the driver occasionally consumes alcohol when not behind the wheel!

 

You have a problem posting in one window?
I think there is a 5000 word limit .
I had that problem a week ago where it would repeat my text and add to the word count.
With the fixes that have been done to the board software, the problems of posting hangups seem to be gone.
I use Netscape 7.2 as a browser on dialup running windows XP home edition on an HP machine.

PS, it is alcohol burning and ......FOOL..... injected!!

I'm an old racer now but still wrench a 540 hp 5.7 L Ford powered sprint car on akly and run a blown 90 Lincoln Mark VII LSC for my good car.

 

Yea I still have the problem not every post but a few now and again. I e-mailed Steve about it and he said it was teh ones over 2000 word count thats what the new update on the server says too...It does seem to be most common when I use IE 6. That's what im on when I ussally have time to post read or post. I own an Ad Design and Photo Restoration studio and we use G4 Mac's there of course with Netscape 7.2. at home I have 3 desk top pc's w/ everything from win 95 to XP depending upon whos you go to and some have IE some have Firefox. Then 1 laptop with XP "IE6" and one Mac w/ OSX NS 7.2 "I use it because I am trying to get a local performace magazine started in my spare time." [I]like I have a lot of that or something!!![/I does seem to be most common when I use IE 6. That's what im on when I ussally have time to post read or post. I own an Ad Design and Photo Restoration studio and we use G4 Mac's there of course with Netscape 7.2. at home I have 3 desk top pc's w/ everything from win 95 to XP depending upon whos you go to and some have IE some have Firefox. Then 1 laptop with XP "IE6" and one Mac w/ OSX NS 7.2 "I use it because I am trying to get a local performace magazine started in my spare time." like I have a lot of that or something!!! LOL That project may not ever get done because it keeps finding it's way to the back burner.

I have not ever got into Sprint cars as far as running them...I love to watch but there isn't very many events for them around here close..occasionally one of the local tracks will bring some in. Most people around here run modified and this last season they tore the last paved track up and made it dirt. So now everybody is racing modified dirt. I only know one guy that does and I have not ever made it over to his sh] LOL That project may not ever get done because it keeps finding it's way to the back burner.

I have not ever got into Sprint cars as far as running them...I love to watch but there isn't very many events for them around here close..occasionally one of the local tracks will bring some in. Most people around here run modified and this last season they tore the last paved track up and made it dirt. So now everybody is racing modified dirt. I only know one guy that does and I have not ever made it over to his shop to do much more than some welding for him.

I raced bomber class for a few years then advanced to stock for a few more. Wrecked my car the week after my main sponsor had went out of business. So was out for couple years and just never went back to points racing again. Now just every once in a while for the fun I'll borrow a car and go out for some heat laps. I still help my family and a few friends that still have cars when we get together or they have trouble and call me.

I sponsor/crew an 89 Blown, NOS, Mustang NHRA Dragop to do much more than some welding for him.

I raced bomber class for a few years then advanced to stock for a few more. Wrecked my car the week after my main sponsor had went out of business. So was out for couple years and just never went back to points racing again. Now just every once in a while for the fun I'll borrow a car and go out for some heat laps. I still help my family and a few friends that still have cars when we get together or they have trouble and call me.

I sponsor/crew an 89 Blown, NOS, Mustang NHRA Drag car that we just got licesened with the NHRA "finally" (they are tough) so it can start racing this season. I bought co. owner/sponsor an 81 Porsche 911T last spring that I plan on building to race SCAA circuit that I am going to drive. Maybe now I can start working on it a little more now that the drag car is 1/2 ready. I dont know enough about the drag car to be much help now that it's running I just put a wrench on what ever I'm told to. I dont know anything about Porsches, turbos, or SCAA either so this will be a fun experinc car that we just got licesened with the NHRA "finally" (they are tough) so it can start racing this season. I bought co. owner/sponsor an 81 Porsche 911T last spring that I plan on building to race SCAA circuit that I am going to drive. Maybe now I can start working on it a little more now that the drag car is 1/2 ready. I dont know enough about the drag car to be much help now that it's running I just put a wrench on what ever I'm told to. I dont know anything about Porsches, turbos, or SCAA either so this will be a fun experince!

Ahhh guess I need to read closer! LOL

BTW...The name Bluegrass...Do you play Bluegrass... or listen to it?

This is Netscape 7.2 lets see if it messe the post up.

 

It got you again!.
Yes, I at least try to pick Banjo a little bit and involved in a Bluegrass music association for the last 5 years.
afba.org if you care to. The association owns it's own music park. We get a lot of big name bands at the summer festivals.
Just came home from an indoor festival.
Your ambitious by the sounds of it and want to do a lot of different things like I uses to.
Good luck.
We better sign off this thread as it has taken a sharp right turn.

 

Yep it got me...ARGGG

I don't like right turns as well...I'm use to straight, left, left, straight! Though if I ever get to do an SCAA track they do right turns... LOL

 

I am not sure that I agree with all of the info posted in the numerous posts to this thread specifically the parts about modern engines not having any overlap. That is not true per say, and it may have been clarified in a later post I don't recall, but there is overlap, it is minimal but there is some. I am not an engine expert, and I am not a forced induction expert but I have built several engines (mainly SBC) with excellent results. The latest is a 406 that dynoed at 490 HP and 520 Ft/lb of torque, using conservative heads (180cc AFR). The whole key to performance in any internal combustion engines revolves around airflow in and airflow out. Does your goal for the engine involve a max racing effort where idle quality and part throttle can be sacrificed for max HP that is made at a high engine RPM (AKA NASCAR cup engine) or do you want improved performance at reasonable engine RPMs and maintain the civility of your engine. It is certainly not practical to say that no performance gains can be realized by freeing up intake and exhaust flow. Take for example the Lt1 powered late model camaro. These cars started out life as regular production Z-28 with 285hp and after intake and exhaust modifications by SLP they were 315 hp with no internal engine modifications. I agree that forced induction sytems combined with today's tunable EFI sytems (Big Stuff III, Accel/DFI, Motec and others) offers huge power from relatively small cubes and can be made downright streetable. However these systems are extremely expensive. It is probably true that they offer more HP per dollar that simple air intake or exhaust changes but I think that the majority of people on this board are not able to dump 5,000 to 8,000 in a forced induction system. Freeing up intake flow by using an aftermarket intake tract (FIPK and others) or reducing backpressure by installing a free flow muffler/cat back system (FM, Magnaflo, spintec, etc) can improve you HP (it wont be 50hp but at certain engine RPMs gains are made) often time these modifications will provide excess flow so that some other part (throttle body, exhaust manifolds) are now the restrictive element in the system. This is the world of hot-rodding....that doesn't mean that you have to replace these other components it is just that in order to increase HP and torque more they would be the next step. So it really becomes a matter of what you replace when and how far you want to go. Some of the comments about exhaust systems were a little disturbing too, especially the part about stock exhaust mufflers providing a certain length necessary to provide correct flow. Backpressure is never good, with that being said it is possible to over scavage the cylinders but highly unlikely given the mostly static variables (cam, heads, rocker ratio, etc) in most of the trucks on this board. Planning an exhaust system to achieve the max Hp and torque for a given engine combination involves tons of variables, involves a boatload of dyno time, and a detailed understanding of pressure wave dynamics. However some generalizations can be made, such as decreasing flow restrictions, (stock mufflers, and unecessary bends and crimps) improve exhaust flow and Hp and torque. On these trucks modifications to components ahead of the cats or the cats them selves is not legal and so pretty much off limits unless you want the smog police after you, these types of mods often **** off the computer and can be pretty irritating in the long run, so I would really just stick with cat back systems. In most cases you will not be able to get your exhaust pipes too big to really significantly hurt flow in a cat back system, the engine may already view some other part of system further up as "open to atmosphere" due to pressure wave tuning and so you are essentially just removing any restrictions and putting a muffler in to get the desired sound. There is a rule of thumb out there that for dual systems about 2.5 inch is all you need and for single systems 3 inch. After that you are basically just increasing noise and cost, there are no real flow benefits. There are exceptions to every rule but the only way to know for sure what is "best" for your particular setup is to tune with a dyno. I don't mean to flame anyone but I don't want anyone thinking that mods they may enjoy doing that are relatively easy to do and do a lot to contribute to the hot-rod experience of turning wrenches, personalizing their vehicles, and good old fashioned bench racing are not worth it performance wise.

 

Ever hear of a paragraph? Not worth the effort to read sorry. Sorry did not mean to be harsh.

 

Sorry... got to typing and forgot about paragraph structure...no need to be harsh

 

I read it..It's a pretty good summary of the begining of the thread..He is bringing the thread back to the original topic and the basics again since we had high jacked it and gotten into a little more than the topic. I wish the board would have let us type more than 200 charecters when we were having the conversation too. I think Bluegrass could help me perform alot better both on and off the track...

Now I do have one question....I've wondered this for a while and thought maybe I just wasn't seeing something that everyone else was. I have heard a lot of people talk about (H pipes) and (X pipes) to equalize the pressure between the banks.... I have never ran them myself. I was at the muffler shop (The local Flow Master dealer/installer) today having an exhuast put on my friends 82 Explorer F100. When he asked them about installing an (H pipe) and they said they would do it if he wanted, but was a waste of money. Does anybody have any actuall dyno #'s of before and after either or both setups on an average streetable vehicle(s)?

I can maybe see an advantage if installed before the cats. "IF" one side becomes restricted then it might would let it flow a little better through and with the other side. Other than that, it seems like to me the (H) style especially would create more turbulance and do more harm than good? The claim "equalize the pressure", Aside from the variances of the valve train on each head "MIGHT" create a differenc but the only other reason I can see for any variance or difference between the pressure is if you ran them both out the same side. Then the opposite side would have more pipe and more bends than the inside would. But it would be so minute especially on a low flow system like a daily driver or even a street car. So how or why would it equal pressure with (H) or (X) on an already fairely equal system? I think I would rather not have the added turbulance of the edges plus two air streams trying to mix in the pipes...

In theroy initialy I thought when it was brought to my attention. I was inclined to think great it would realive some pressure if there is a higher side...But since for every action there is an equal and opposite reaction. That means that I would be adding pressure if there was a lower side. Why not correct the problem instead of trying to by pass it?

 

Well, I read it...and it WAS worth it.
Not saying I agreed with everything, but it was a nice read.

Thanks for the input, BC28036!