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- 03' Mazda Protege 5
Do you know what page that spread sheet is on? Dont have the time to go through 40+ pages. So what other things would I have to take into account if I used a bigger throttle body?
NA Tech Race to 100whp per 1000cc's
- Thread starter LordWorm
- Start date
Do you know what page that spread sheet is on? Dont have the time to go through 40+ pages. So what other things would I have to take into account if I used a bigger throttle body?
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- 02' Protege ES (Gone)
16' Mazda 6 sport manual
post #370
Lordworm did you ever post a finished one?
Lordworm did you ever post a finished one?
Nope... one day
I'd actually like to move it to an interactive online webpage - so i can back it with a database storing a variety of different "Default" engines, for comparison and to save people data entering all the junk.basically you'll need to be spinning the engine at ludicrous speeds...or running a massive VE well over 100%. In fact, if you run the calcs in the spreadsheet you'll see that a more or less stock FSDE would benefit from a SMALLER throttlebody.
Basically, you are attempting to get 180ft/sec flow at peak RPM - so you want an intake that is just enough to do this. That is to say, if you go any bigger you wont achieve 180ft/sec, if you go smaller you will get far higher than 180ft/sec. Either of these are "sub optimal"... The spreadsheet calculates "intake pipe diameter" - which also includes the throttlebody...you can safely add a bit of extra throttlebody size to the calculation though, to account for the throttle blade. In fact, teh 55mm throttlebody has enough headroom to support 200 crank horsepower....which lets face it, is going to be far beyond what most people are going to get out of the engine NA.
essentially, there is absolutely *no need* to oversize the throttlebody for the FSDE in NA form.... no need at all.
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My guess would be that for relatively low power, the ability to turn down the fuel pressure would result in less fuel being delivered- which would lean out the mixture and thus making more power. I know this worked on the last car I had (Saturn SC).
Once you start adding up parts and increasing the air flow, you'll probably need to re-add the fuel you took out and possibly add in more.
wouldnt really help. fuel management units are designed when boost pressure goes up, fuel pressure will go up accordingly.
a regular adjustable fuel pressure regulator wouldnt really help you either since only adjustments are to be made in certain areas. a engine management unit is much more useful and acutally benificial.
a regular adjustable fuel pressure regulator wouldnt really help you either since only adjustments are to be made in certain areas. a engine management unit is much more useful and acutally benificial.
At least for low power, LESS fuel is what you want. The car runs stupid rich as it is in OPEN LOOP operation as it is.
okay good to know... i always thought rich = more air than fuel and lean was the other way around... i always get it confused but now i know... i guess i could take that out of the list for the power im making now... 626 manifold seems to be doing justice for people going for top-end power
and do any other throttle bodies fit our cars? perhaps a miata or millenia? or the v626? b2000?
and do any other throttle bodies fit our cars? perhaps a miata or millenia? or the v626? b2000?
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Woohaa, lots of posts to reply to.
sqrt(Pn/Po)*Fo = Fn
where Pn is the new pressure, Po is the old pressure, Fo is the old flow rate, and Fn is the new flow rate. So, assuming 280cc/min @ 43.5psi, an increase to 50psi will give you an injector flow of 300cc/min. Of course, you need to consider the maximum rated pressure for the injector as well as how much additional pressure in the fuel system the pump will deal with before you get cavitation (or potentially damage to the pump).
The benefit of upping the pressure will only be felt if you have control over your fuel delivery (piggy back AFC or a stand alone management system) - see my next point for details
Another benefit to increasing the fuel pressure is improved fuel atomization .
Remember, that whilst an NA engine may not be "boosting" pressure is going to change from around 25"hg to 0"hg from idle to wide open throttle/max load. So the increase in fuel pressure in line with an increase in engine load is a requirement of an NA motor just as much as it is a boosted engine. Whether spending $100 on an adjustable regulator for an NA car is required or not is a different story - but a reg of some sort is required, otherwise the fuel pressure will be pegged at the spring pressure of the reg, and as the engine begins consuming greater amounts of fuel as load goes up, and revs rise, you could start running very low fuel pressures, and max the injectors very quickly.
the ECU pulses the injectors for a given number of milliseconds, dependent on fuel delivery requirements for a specific rpm vs load map point (at its most simplest - of course there are other fuel corrections and so forth...but theres no need to go into that for the sake of this explaination). lets say that the ecu's minimum pulse is equivilant to 5% of duty. 5% of 280cc is a stack less than 5% of 440cc... quite simply, if you are not changing your ecu - DO NOT CHANGE your injectors....forgetting the fact that the stock injectors are going to be more than enough for anything you are ever likely to do NA, and that you can get a spot more head room later on with an adjustable fuel pressure regulator - putting 440's in an NA FSDE running pump gas is, in a word STUPID (if you were running methanol you'd want 800cc/min injectors but thats because methanol's going to require 4x as much fuel to achieve a desirable Air Fuel Ratio - basically if you are not going to be converting to alcohol, or some other exotic fuel there is ZERO need to buy bigger injectors)
BinoMP5 - I'm not trying to have a go at you here - i'm just pointing out that your injector fetish is a little bit silly and you're better off spending money else where. Put the money towards a stand alone. Once you've got a stand alone, go get a sard regulator - chances are thats all you'll ever need to touch on your fuel system. I have a sard in my car and i'm very happy with it (i bought it because my stock regulator was damaged when pulling the manifold off a while ago....so i needed a regulator and thought i'd buy something nice - really though if i never broke the stock reg, i probably never would have swapped it out!)
I don't know if you'd NEED one NA...having never put a pressure gauge on a standard one to see how well it holds up under high NA output - but there are certain benefits to getting one. Upping the fuel pressure gives you a little more head room in the injectors. Injectors are quoted at a specific capacity at a specific pressure. If you increase the pressure you increase the amount of fuel they flow (to a point). According to my favorite fuel injector online calculator, the formula for working out the impact of increasing pressure is:
sqrt(Pn/Po)*Fo = Fn
where Pn is the new pressure, Po is the old pressure, Fo is the old flow rate, and Fn is the new flow rate. So, assuming 280cc/min @ 43.5psi, an increase to 50psi will give you an injector flow of 300cc/min. Of course, you need to consider the maximum rated pressure for the injector as well as how much additional pressure in the fuel system the pump will deal with before you get cavitation (or potentially damage to the pump).
The benefit of upping the pressure will only be felt if you have control over your fuel delivery (piggy back AFC or a stand alone management system) - see my next point for details
Another benefit to increasing the fuel pressure is improved fuel atomization .
The problem with tinkering with fuel pressure on the standard EMS is that you are talking about fairly small changes - changes that are well within the stock computer's ability to learn around. It is likely that the ecu will simply learn around your fuel pressure trick, and put you back to square one.
There are 2 types of fuel pressure regulators i know of - Rising Rate, and 1:1 ratio boost ref regulators. a rising rate will increase pressure by a ratio (say 2, or 3:1) for every psi of increased manifold pressure. A 1:1 will give you 1 psi more fuel pressure for every psi increase in manifold pressure. The standard fuel regulator is a 1:1 type (and really, thats all you should be ever using. huge high power import drag cars use 1:1.... mind you they are using 1:1's that flow insane amounts of fuel - I have a Sard standard adjustable 1:1 ratio fuel reg in my car).
Remember, that whilst an NA engine may not be "boosting" pressure is going to change from around 25"hg to 0"hg from idle to wide open throttle/max load. So the increase in fuel pressure in line with an increase in engine load is a requirement of an NA motor just as much as it is a boosted engine. Whether spending $100 on an adjustable regulator for an NA car is required or not is a different story - but a reg of some sort is required, otherwise the fuel pressure will be pegged at the spring pressure of the reg, and as the engine begins consuming greater amounts of fuel as load goes up, and revs rise, you could start running very low fuel pressures, and max the injectors very quickly.
See my second point... a reg for you wont do anything. Also going to big 440cc injectors is a bad idea, because that is a HUGE jump in capacity. The stock ecu wont be able to get around those injectors - it will run at minimum duty and even then it'll be too rich.
the ECU pulses the injectors for a given number of milliseconds, dependent on fuel delivery requirements for a specific rpm vs load map point (at its most simplest - of course there are other fuel corrections and so forth...but theres no need to go into that for the sake of this explaination). lets say that the ecu's minimum pulse is equivilant to 5% of duty. 5% of 280cc is a stack less than 5% of 440cc... quite simply, if you are not changing your ecu - DO NOT CHANGE your injectors....forgetting the fact that the stock injectors are going to be more than enough for anything you are ever likely to do NA, and that you can get a spot more head room later on with an adjustable fuel pressure regulator - putting 440's in an NA FSDE running pump gas is, in a word STUPID (if you were running methanol you'd want 800cc/min injectors but thats because methanol's going to require 4x as much fuel to achieve a desirable Air Fuel Ratio - basically if you are not going to be converting to alcohol, or some other exotic fuel there is ZERO need to buy bigger injectors)
They sure are! in fact, 280cc injectors at a maximum of 80% duty will quite happily support around 190 crank horsepower at 43.5psi fuel pressure. If you want to live on the wild side and bump the maximum duty to something around say, 90% (which would be fine, for short bursts at maximum injector usage) - you can get 210 to 215 crank horsepower out of them... push the fuel pressure up to around where mine's running these days, about 55psi at wide open throttle, you can produce 240 crank horse power. Now, if you were going to have a tilt at 100whp per 1000cc's, you'd probably look at 330cc injectors just to keep everything a little less on the edge... but only if you had a stand alone (which you would if you were chasing these kind of numbers). Quite simply - if you're not touching the ECU, don't bother touching the injectors. If you are not intending on making astronomical NA power (or intend on using some sort of crazy alcohol based race fuel), don't bother touching the injectors.
BinoMP5 - I'm not trying to have a go at you here - i'm just pointing out that your injector fetish is a little bit silly and you're better off spending money else where. Put the money towards a stand alone. Once you've got a stand alone, go get a sard regulator - chances are thats all you'll ever need to touch on your fuel system. I have a sard in my car and i'm very happy with it (i bought it because my stock regulator was damaged when pulling the manifold off a while ago....so i needed a regulator and thought i'd buy something nice - really though if i never broke the stock reg, i probably never would have swapped it out!)
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both RRFPR and constant rate FPR will "raise fuel pressure according to vac pressure". Its the *rate* at which it will raise/drop it thats the issue.
for example, from 0"hg to 2"hg (which is roughly a difference of 1psi) a 1:1 FPR will pull the pressure down by 1 psi...so if the 0"hg pressure is 50psi, the 2"hg pressure would be 49psi.
A RRFPR with a 2:1 ratio will pull the pressure down 2psi, a 3:1 will pull it down 3psi and so forth.
I find it *exceedingly* hard to believe the stock unit is an RRFPR....it is vastly more likely that it is a constant rate FPR....
+1 on the not needing injectors NA. I put 440's on while preparing to turbo, just to make sure the emanage could deal with them ok, which it did. Prior to tuning, there was a poorly running, smoky engine indeed! With the WBO2 I could see the stock PCM trying to correct the mixture and then reach it's limit, give up and go open loop. When I had to abandon the turbo project due to lack of funds
, there was no point keeping the injectors, so they were removed. I'm only up to about 73% duty cycle on the stock injectors at 7,500rpm. Actually, by stock I mean the 280cc injectors from the 2.0 that I've installed in my 1.8, which normally has 235cc.
, there was no point keeping the injectors, so they were removed. I'm only up to about 73% duty cycle on the stock injectors at 7,500rpm. Actually, by stock I mean the 280cc injectors from the 2.0 that I've installed in my 1.8, which normally has 235cc.
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- 03' Mazda Protege 5
I have a 626 Intake manifold coming and I had a few questions:
1: Is the 626 intake manifold better than our stock ones for NA purposes?
2: Would it make any benefitial differences to the 626 intake manifold if I gasket matched it and extrude honed it??
I know there has probably been a million questions about this but search's have not done me any good. I was under the impression that the 626 intake manifold would improve HP on an NA car but I have been seeing alot of FI guys using it so I wanted to get that cleared up and to see if I should really put this manifold on my car if I am staying NA
1: Is the 626 intake manifold better than our stock ones for NA purposes?
2: Would it make any benefitial differences to the 626 intake manifold if I gasket matched it and extrude honed it??
I know there has probably been a million questions about this but search's have not done me any good. I was under the impression that the 626 intake manifold would improve HP on an NA car but I have been seeing alot of FI guys using it so I wanted to get that cleared up and to see if I should really put this manifold on my car if I am staying NA
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Loose a little low end, gain some top end. Is the loss in low end worth the gain in top end for a daily driver? That's my question.
Well, gasket matching the intake manifold alone isn't really enough if the size of the openings on the cylinder head are smaller.
What I was going to do when I put my VTCS-less manifold on (but never did) was to make a "blank" gasket out of some type of stiff paper to be used as a template for how far I should port the intake. I'd attach that to the intake side of the cylinder head and use a razor blade to cut out the intake openings. Then I'd transfer this to the intake and port it accordingly. I have no idea what the head's ports look like in relation to the manifold- could be bigger, could be smaller, could be the same size.
I hear that. Does anyone know which years of 626 manifold will work? I believe all the manifolds will bolt up, but issues with the pre-2001 manifold arise in terms of fuel rails and such.
xboxlivemonkey
Member
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- 03.5 Msp
look for alejo_nin , he lives near me , and has a write up on the manifold , sure he would not mind a few questians from you , and the manifold year should be a 2000 
I hear that. Does anyone know which years of 626 manifold will work? I believe all the manifolds will bolt up, but issues with the pre-2001 manifold arise in terms of fuel rails and such.[/QUOTE]
I hear that. Does anyone know which years of 626 manifold will work? I believe all the manifolds will bolt up, but issues with the pre-2001 manifold arise in terms of fuel rails and such.[/QUOTE]
