Some questions about N/A

[Lord_Zath]

OK, so I've done a ton of reading on this board and it has helped immensely, BUT I do have some questions.

I think my situation's kinda unique in that I'm not trying to get humungous horspeower gains and I'm also looking to get better gas mileage.

I decided to go N/A over F/I because I don't need to use premium gas, I'll have more hp over the entire powerband, and the added hp will help in terms of gas mileage. Am I correct?

What I'm thinking of doing is Injen CAI, both cams, and a Racing Beat cat-back exhaust. I was considering putting a header in and doing that stuff, but I could have that check engine light problem, right? Also, it wouldn't pass most emissions with the 1st cat removed?:confused:

I doubt if I'd go farther than the CAI-Header-Catback setup for hp. I'm thinking once that's done, change other things such as pulleys and torque convertor (I have an auto). Would that yield more gains for money spent than a port-polish?

Thanks for any and all answers!

LZ

[Turbo Matty P]

You can't have your cake and eat it to. The only way I've seen better gas mileage AND power was with my jackson racing supercharger. It made the motor more efficient increasing mileage, however when I got up on it it used more fuel. It all depends on how you use your newfound power.

P&P is great for people who are looking to do it correctly. Replacing the cams will help out a good deal after the P&P is done. Do not over look the benefits of gasket matching the intake manifold to the head after/while this is done. Similar to exhaust, you're only going to flow as much as your smallest bottle-neck. It could be your intake, throttle body, intake manifold, but it more than likely WONT be your head. If you want to do it right and make gobs of power do it all at one time.

Anyone make a large bore TB for the FS-ZE / FS-DE??

[mopiko]

with the mod you'll plan to use you won't see much hp gains, as a matter of fact you might get worse gas milages. But only way you can find out is to try it yourself.

Also if you work the head with port/polish and higher compression ratio piston you'll end up needing premium fuel anyway... just a thought.

[Installshield 2]

A couple of things...with NA you won't gain power over the entire rev band...but more than likely just in the higher sections...a couple of bolt-on's will help with torque a bit, but help with high end power more...and cams, porting issues, increased valve sizes etc. mostly increase the peak power of the powerband, and move it higher up in the rev range...

[twilightprotege]

any car that makes more power uses more fuel. power is DIRECTLY linked to fuel use.

what sorta power are you wanting????

[Lord_Zath]

Well I'm not looking for a lot of power. Just something to give it more zip I suppose. I'm not looking to drag race/street race. I think the car's great but I'd really like to get a little more power and a little more mileage out of it... Perhaps I should go a different route? Try to "free up" horsepower?

Also, I realize that I posted this outside the F/I forum, but if there's not really a way to add hp and mileage at the same time, I might just go turbo... but would I HAVE to put in premium fuel if it's say a standard Flyin' Protege turbo kit running the recommended 6psi???

[Installshield 2]

Originally posted by twilightprotege
any car that makes more power uses more fuel. power is DIRECTLY linked to fuel use.

what sorta power are you wanting????

But it gets much more complicated than that very quickly...

making an engine more powerful will not make it less efficient in every area...it is directly related to an engine's work...a slow loafing engine will almost always get worse gas mileage than a buzzy one...The better the engine's ability to stay at a certain speed with no throttle input the better the mileage...

There is no brief way to explain this...I will try to dig up some old stuff to make this more understandable...

In some cases you are right, but in some cases engine modifications will increase gas efficiency and power...

[twilightprotege]

i'd say your best option to free up power and get as best mileage as you can is weight redcution....pulleys, lightened crank, take stuff outta the car....

yep, install is right...damn i'm always to general.......

[Installshield 2]

Originally posted by twilightprotege
i'd say your best option to free up power and get as best mileage as you can is weight redcution....pulleys, lightened crank, take stuff outta the car....

yep, install is right...damn i'm always to general.......

but in general you are correct...

The complication arrives when new performance parts are installed and the driver drives the car much harder than before...Then reporting back "these parts make the engine get horrid gas mileage"...but the bad mileage didn't happen becuase of the parts themselves most likely, more becuase the car was then driven like it was stolen...

Obviously huge boost applications that require gallons of more fuel than stock will eat up a lot of gas...in some cases even when the car is driven easily...

But take this for example...If you hang a bunch of well designed good bolt-ons off of a Protege, then drive the car identically to the way you did before, chances are you will get better mileage than before the modifications...The parts will help increase effiency, making more power with the same amount of work...thus to do the same amount of work as before the engine needs less fuel....So for the engine to cruise at 75mph with the modifications, the extra effiecency helps it do it with less fuel than before...Not a huge difference, but in some cases enough to make up a few mpg's...

that is an extremely flawed way of looking at it. there are hundreds of other factors that need to be plugged into the equation before in order for it to be accurate...That example merely touches on the complexities...

Since this thread is mostly about bolt ons, I will leave it at that...if you install good parts and drive the car identically to the way you do now, you definately won't loose gas efficiency and in some conditions gain some...

[Captain KRM P5]

but would I HAVE to put in premium fuel if it's say a standard Flyin' Protege turbo kit running the recommended 6psi???

Steve, under any kind of forced induction you will need premium gas to avoid detonation, knock, et al. With cams I do not think you need premium gas, but you are advised to get adjustable cam gears to wring the most power out of them. There was a dyno posted recently of someone who actually lost power installing just the cams.

Another N/A option would be to install high compression pistons. This will certainly require the use of premium gas and according to some, fuel management, to avoid knock and get the most power out of them.


The only way I've seen better gas mileage AND power was with my jackson racing supercharger.

I actually get 20 miles more per tank or 1.7 more miles per gallon with my turbo installed. Could just be an oddball of the group, but it is true according to my fill up receipts and odometer.

Its been said above and I concur that most of your horsepower from mods such as intake and exhaust will be felt in the top end of the power band. My first two mods were in the Injen CAI and Racing Beat Catback and I can say I felt the power moreso in the higher gears.

If you plan on spending a good deal of money on power, your horsepower : dollar ratio is best served by going turbo.

Although another member of this forum and I were speaking with Corky Bell about using his rising rate fuel pressure regulator to simply add more fuel to an NA setup.

[Dexter]

so you get like 40MPG now Ken???

[Captain KRM P5]

OOPS - sleep deprived. let me edit that - done. changes made in bold.

[PaulMP3]

FYI, i get around 28mpg boosting 7.5psi.

[Lord_Zath]

Originally posted by Installshield 2


Since this thread is mostly about bolt ons, I will leave it at that...if you install good parts and drive the car identically to the way you do now, you definately won't loose gas efficiency and in some conditions gain some...

That's precisely what I'm looking to do. I'd like to add some hp and perhaps help out mpg, but I don't want to have to switch fuel grades to do so. I doubt I'd get up on it that much. I used to own a 2000 Trans Am w/310 hp, so I've kinda/sorta gotten my need for speed taken care of. I'd just like a few extra hp and another mpg or two.

Perhaps the weight reduction scheme would work best? Stuff like switching to lighter wheels, etc? What kinds of things could be done to reduce weight yet keep most of the car's features intact? I probably won't get into this until next spring since winter's coming up and I don't think I'd want to reduce weight going into snow season!

Thanks for all your replies!

LZ

[Installshield 2]

Assuming you have the 16" wheels stock, it will be expensive to get much lighter than them...They weigh in at about 16lbs each, which are some of the lightest cast production wheels in the market...There are some Forged 16" and a couple of cast wheel options that will shave off a few more pounds of unsprung weight...but again anything forged (which will be by far stronger than really lightweight cast wheels) will be expensive...

Since you have an auto, your only option is a crankshaft pulley upgrade...I haven't researched them a lot for protege's, but I do know of 1 or 2 that are available...some love them, some hate them...They can cause A/C kickon problems at idle, but nothing extremely noticable (just sometimes makes the engine stumble a little)...but are good for a couple of hp released...

exhuast bolt ons will never change the current gas requirements...so things like a header or cat-back exhuast will still work perfectly fine with regular unleaded...Intake mods hold pretty much the same, unless you somehow introduce massively better air flow, raising combustion chamber heat and making detonation a problem...You will not do that with any bolt-on intake...Cams are arguable...They do allow more air into the chambers at higher rpm, and at those speeds heat is already a problem...to be on the safe side i would recommend using premium, but it probably isn't a necessity...The ECU still runs very rich with all of these mods, which acts as a buffer for pinging...and the ecu can trim in more fuel if the MAF senses more airflow...so even though you are gaining power, you still will be fine as far as detonation with regular gas...

[Lord_Zath]

Ok thanks that answers many of my questions. But could you tell me more about headers? By installing one, what am I looking to gain? Am I taking any chances with the car becoming non-street legal?

Thanks for all your help!

LZ

[twilightprotege]

headers you will loose mpg because there isnt as much back pressure in the exhaust and therefore some unburnt fuel can go straight out the exhaust if the stock cams have a slight overlap (which i'm sure they do)

gains otherwise will be from nothing to 10whp (AWR). dont know about street legality as i'm an aussie!

[zmepro]

get the headers, look in my sig, there is a fatty group buy going on right now for them, there is lots of info over there

[glyph]

zath, i dont see what car you have... did i miss it?

[Captain KRM P5]

Originally posted by Lord_Zath
Ok thanks that answers many of my questions. But could you tell me more about headers? By installing one, what am I looking to gain? Am I taking any chances with the car becoming non-street legal?

Thanks for all your help!

LZ

If you eliminate both catalytic convertors, your car will not pass emissions. If you eliminate the first cat but wire in both o2 sensors properly (one before and one after the remaining catalytic convertor) your car won't throw a check engine light and your emissions will still be pretty clean.

When you eliminate the cat(s) on an exhaust system you are reducing the restriction on airflow out of the exhaust, reducing bak pressure and thus gaining power.

[Captain KRM P5]

Originally posted by glyph
zath, i dont see what car you have... did i miss it?

03 Protege5, laser blue with sport automatic transmission. :) and he babies it well

[Lord_Zath]

hell yea It's at 887 miles right now and I bought it in June!

That's gonna change soon tho as winter comes and I'll be forced to drive it to work and such.

I'm thinking springtime is a good time to do some upgrades ;-). I just want to get an early start so I know what to look for and order it over the winter time and store it for a few months :-).

[Installshield 2]

Originally posted by twilightprotege
headers you will loose mpg because there isnt as much back pressure in the exhaust and therefore some unburnt fuel can go straight out the exhaust if the stock cams have a slight overlap (which i'm sure they do)

gains otherwise will be from nothing to 10whp (AWR). dont know about street legality as i'm an aussie!


Back pressure will always decrease gas mileage...Loosing back pressure in every way is good...Back pressure is caused by restrictions in the exhuast system that don't allow exhuast gasses to escape...back pressure only builds at higher rpm...This is the reason that most aftermarket exhuasts give the gains in the higher regions of the rev band...

You don't really loose mpg with a header becuase of decrease in back pressure (it illminates the stock downpipe, which is where most of the back pressure is coming from on a protege)...So with a protege it will help relieve lack of exhuast vacuum, and increase gas mileage...gas efficiency is directly related to an engine's work, and in a case where some of the restriction is released the overall work needed to push the exhuast gasses out of the engine is decreased...

Now with cam overlap things get tricky...Overlap refers to how long both intake and exhuast valves are open simultaneously...Overlap will cause a decrease in gas mileage in some cases becuase during the intake stroke of the cylinder exhuast movement is momentarily haulted...Cam overlap is rarely aggressive enough to actually pull exhuast gases back into the engine after the exhuast stroke (which is the intake stroke on a 4-stroke gasoline engine), but it is usually enough to counter the exhuast gas movement to the point where it is significantly "slowed" (think of it this way...there is a vacuum of gas moving out of the exhuast, and if the cylinder is moving downward, which is the intake stroke, and the exhuast valves are open...it tries to pull the gas particles back into the engine...it doesn't pull long enough to actually get the gasses back into the engine...but enough to slow the gasses moving the other way down)...

So in a case such as this, at the next exhuast stroke the gasses are not moving as much as they could have been...and the engine then needs to push on the gasses to get them moving again...This decrease gas efficiency, becuase more work is needed to move the exhuast out overall...

A header will help this, despite cam overlap...The long tube design makes this more apparent by allowing the gasses to stay "unmerged" longer...so the engine then needs to only push on that particular cylinders exhuast gasses at each given time...Mix that with better exhuast system breathing overall and gas mileage can be increased...

[twilightprotege]

yeah i think my cam guy dialed in 6-8 degrees of overlap with my cams. i really need to get an exhaust upgrade....

damn haltech ecu, awr header and pipe....which to do next ;)

[DooMer_MP3]

Both! :D

[glyph]

i'd say go header first, from what little knowledge I have

[twilightprotege]

i'm leaning haltech way at the moment because i'll be able to take a big advantage of the heaps extra oxygen i'm not getting with my ported head and big cams....someone would ship me an awr header for free and i'll get the haltech! sounds fair :p

[DooMer_MP3]

Actually, I'm willing to bet the cost/benefit between a header/exhaust and haltech would lean more towards the header/exhaust side. You've done a great job at allowing the engine to breath much better before that stock exhaust, but your stock exhaust is such a bottleneck right now. I'm betting a header on your setup will yield more than 10whp that we get on otherwise stock vehicles.

Chris

[Installshield 2]

Originally posted by DooMer_MP3
Actually, I'm willing to bet the cost/benefit between a header/exhaust and haltech would lean more towards the header/exhaust side. You've done a great job at allowing the engine to breath much better before that stock exhaust, but your stock exhaust is such a bottleneck right now. I'm betting a header on your setup will yield more than 10whp that we get on otherwise stock vehicles.

Chris

And so would good tuning...

Chris is right...The stock exhuast system, if it is anything like ours, is the biggest restriction on the stock engine overall...and then right after than comes the ECU...BOTH NEED to go for the most power, which one you do first is up to you....With good tuning and a Header exhuast you will see a large chunk of power...probably 10-20whp with the tuning alone (depending on how aggressive the mixture and ignition timing)...Also a lot of members on this board are getting 15whp or more from the AWR header alone...I haven't seen any gains like that with anything but the AWR piece...but Equinox with an Injen and a AWR Header pulled 126whp and over 131lb/ft of torque...never saw his base run though, if he did one...

[Lord_Zath]

Hmm interesting. So you guys are saying work on the exhaust system first, then towards intake?

So like cat-back exhaust, header, cams, CAI?

What kind of gains would I be lookin at?

How much would it all cost?

I'm not sure if I'd be wanting to do a lot of tuning; this is the first car I've ever owned new (out of 3) and I've ever really wanted to modify, so I don't know a whole lot about this stuff (as you can tell)!

Thanks again for all the info!

LZ

[Captain KRM P5]

Originally posted by Lord_Zath
Hmm interesting. So you guys are saying work on the exhaust system first, then towards intake?

So like cat-back exhaust, header, cams, CAI?

What kind of gains would I be lookin at?

How much would it all cost?

I'm not sure if I'd be wanting to do a lot of tuning; this is the first car I've ever owned new (out of 3) and I've ever really wanted to modify, so I don't know a whole lot about this stuff (as you can tell)!

Thanks again for all the info!

LZ

AWR 4 to 1 header - $515
Racing Beat Catback Exhaust - $440
Injen Cold Air Intake - $240
Intake and Exhaust Cams - $390
MIL Eliminator (to trick the CEL from use of headers) - $30

So far $1615

[twilightprotege]

the biggest benefit of the haltech will be to raise the rev limit. i hit 6500rpm and it's like damn it, i have to shift now. the car so wants to keep going.

both exhaust and ecu will give great benefit...together they'll be farking great....just need money

[Lord_Zath]

wow... it's been a long time since I posted questions. It's kinda cool seeing how much myself and the community has progressed in the past two years.

I now have intake, header, exhaust, udp for performance, and I think I'm near the end of my power modifications. Anything else after this costs lots more. Thanks everyone for your help.

I have achieved my goals of better power and better gas mileage - I don't gun it all the time, and I've found the car gets consistently higher mileage - about 2 mpg more or so. Not huge, but every little bit counts :)

[twilightprotege]

nice old thread!

[glyph]

no kidding. Especially since I went turbo...

[SpicyMchaggis]

Holy old thread batman.