big puddle
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Originally posted by Slainte
i've read that the learning ECU will actually decrease the performance of your mods over time, because it wants to re-create the stock specs of the engine... i.e. if you get an intake, it will perform better for a while, but once the ECU starts learning, it will reset the A/F ratio etc. to make the engine perform as if it were stock. thus the priority to get a hondata flashed ECU. any truth to this theory?
i've read that the learning ECU will actually decrease the performance of your mods over time, because it wants to re-create the stock specs of the engine... i.e. if you get an intake, it will perform better for a while, but once the ECU starts learning, it will reset the A/F ratio etc. to make the engine perform as if it were stock. thus the priority to get a hondata flashed ECU. any truth to this theory?
Most Hond ECU's will attempt to keep a value closest to stock during closed loop operation.
So yes, when you add an intake/exhaust, your air/fuel ratio goes a little leaner, giving you a bit more power. Over time, your car will readjust and add more fuel, bringing the mixture back down. Yes, it will cause a VERY slight loss in HP, however, you do have more air, more fuel, and a better flowing engine which is still where the majority of your power comes from. So in conclusion, let's say you gained 10hp with intake/exhaust/header. Over time that may come down to 8-9hp once your ECU readjusts.
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Rep Power: 0 as far as the ecu goes, it will always be the same, yeah if for a while u decide to leave several mods on the car, but ive had a cai for at least two years, maybe its since my car keeps getting mods that my car will only go as fast as the mods will let it, hmmm good opposing arguement ill have to ask someone about that ecu question
nice job slainte
eric
nice job slainte
eric
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Originally posted by S2000man01
Well, stoichmetric air/fuel is 14.7:1. However, to prevent detonation, you probably don't want to be any higher than 13.7-14.0:1.
Most Hond ECU's will attempt to keep a value closest to stock during closed loop operation.
So yes, when you add an intake/exhaust, your air/fuel ratio goes a little leaner, giving you a bit more power. Over time, your car will readjust and add more fuel, bringing the mixture back down. Yes, it will cause a VERY slight loss in HP, however, you do have more air, more fuel, and a better flowing engine which is still where the majority of your power comes from. So in conclusion, let's say you gained 10hp with intake/exhaust/header. Over time that may come down to 8-9hp once your ECU readjusts.
Well, stoichmetric air/fuel is 14.7:1. However, to prevent detonation, you probably don't want to be any higher than 13.7-14.0:1.
Most Hond ECU's will attempt to keep a value closest to stock during closed loop operation.
So yes, when you add an intake/exhaust, your air/fuel ratio goes a little leaner, giving you a bit more power. Over time, your car will readjust and add more fuel, bringing the mixture back down. Yes, it will cause a VERY slight loss in HP, however, you do have more air, more fuel, and a better flowing engine which is still where the majority of your power comes from. So in conclusion, let's say you gained 10hp with intake/exhaust/header. Over time that may come down to 8-9hp once your ECU readjusts.
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Rep Power: 0 The whole key to getting any significatn gains with a 7th gen is the ECU. It just won't let the engine take full advantange of the theoretical values from all the mods.
If you go back to the olden days where engines did not have electronic computer controls, you would almost always have to add one or two mods for every mod you put on. But as you did that you could realize the full gains by tuning.
For instance if you put on header(s), intake manifold, and a free flow exhaust, you could adjust timing to take advantage of these and you would also need to go to a bigger carb and/or bigger jets to take advantage of that better breathing.
The stock ECU on our cars just won't let you take full advantage of those sorts of mods.
If you go back to the olden days where engines did not have electronic computer controls, you would almost always have to add one or two mods for every mod you put on. But as you did that you could realize the full gains by tuning.
For instance if you put on header(s), intake manifold, and a free flow exhaust, you could adjust timing to take advantage of these and you would also need to go to a bigger carb and/or bigger jets to take advantage of that better breathing.
The stock ECU on our cars just won't let you take full advantage of those sorts of mods.
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Rep Power: 0 One little problem I have with the HP claims for some mods, such as intakes in particluar, is that they often cite the gains at the top of the RPM curve. It's up there and you can measure it, but at the high end of the RPM, what good is it in daily "spirited" driving?
I noticed on my last trip that there was a really bad flat spot between 75 and 90 MPH. That's a point where I like to have a little power in certain freeway encounter situations. Thats another reason why I took off my FIPK today.
I just went and got a K&N stock type replacement filter and put it on with the stock filter box, left off the resonator box, and jus put big hose from the filter box into the heat shield area that came with the FIPK.
We'll see how this works out on the next long trip.
I noticed on my last trip that there was a really bad flat spot between 75 and 90 MPH. That's a point where I like to have a little power in certain freeway encounter situations. Thats another reason why I took off my FIPK today.
I just went and got a K&N stock type replacement filter and put it on with the stock filter box, left off the resonator box, and jus put big hose from the filter box into the heat shield area that came with the FIPK.
We'll see how this works out on the next long trip.
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I would appreciate your comments on my perceived loss of torque and early downshifting when you get a chance.
I've observed this with OBX, AEM, and FIPK. All SRI's.
I would appreciate your comments on my perceived loss of torque and early downshifting when you get a chance.
I've observed this with OBX, AEM, and FIPK. All SRI's.
Last edited by Bartkat; Apr 8, 2003 at 09:01 PM.
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From: Milwaukee, Wisconsin, US
Rep Power: 400 Re: s2gman
Originally posted by SaiyanMatador
very true, but since the mods are aftermarket, the car wasnt made to handle the extra 575 hp u just put on with that venom nitrous kit thatll help u run 7 flat stock. in other words, maybe its just your other accessories that need to be replaced in order to achieve that true hp from adding on new aftermarket parts.
very true, but since the mods are aftermarket, the car wasnt made to handle the extra 575 hp u just put on with that venom nitrous kit thatll help u run 7 flat stock. in other words, maybe its just your other accessories that need to be replaced in order to achieve that true hp from adding on new aftermarket parts.
Of course, if you are running very lean... in other words, to the point that the car can no longer add enough fuel and is maxed out, then it's time for a fuel system upgrade. You can always get a stand alone engine management system as well, and set things the way you'd like them to be.
as far as the ecu goes, it will always be the same, yeah if for a while u decide to leave several mods on the car, but ive had a cai for at least two years, maybe its since my car keeps getting mods that my car will only go as fast as the mods will let it, hmmm good opposing arguement ill have to ask someone about that ecu question
Originally posted by Bartkat
S2000man01.
I would appreciate your comments on my perceived loss of torque and early downshifting when you get a chance.
S2000man01.
I would appreciate your comments on my perceived loss of torque and early downshifting when you get a chance.
If you increased horsepower, that means the ECU would shift later, not earlier in any given equal situation. However, that's a pretty hard thing to judge without being able to take precise measurements, so I wouldn't read too much into it. Even weather and temperature can affect the power you are making, so that could be one reason alone you thought it was downshifting earlier.
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Rep Power: 0 Nope. It really does downshift at lower speeds. I have a test hill where I do runs both ways and repeat. I've also driven each SRI for at least 5000 miles. What I'm saying is that if the HP gain is all on the top end, it really isn't doing me any good in routine highway driving. The only other thing I can think of is that the big air filters are giving a different MAP so the ECU is seeing some sort of difference and trying to adjust by shifting.
I guess I'd have to look at how the HP and torque curves change with these intakes. I'm thnking there may be less torque or the peak torque RPM is changed. Horsepower without torque really doesn't mean a whole lot, I think.
Anyhow I put in the K&N stock replacement with the hose and slipped a OBX SRI tube over the hose so it looks purty. Took it out to the hill and made two runs and it didn't downshift, and maintained speed (I always do this test in cruse control at 70 MPH).
I guess I'd have to look at how the HP and torque curves change with these intakes. I'm thnking there may be less torque or the peak torque RPM is changed. Horsepower without torque really doesn't mean a whole lot, I think.
Anyhow I put in the K&N stock replacement with the hose and slipped a OBX SRI tube over the hose so it looks purty. Took it out to the hill and made two runs and it didn't downshift, and maintained speed (I always do this test in cruse control at 70 MPH).
Last edited by Bartkat; Apr 8, 2003 at 09:53 PM.
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From: mr. and mississsauga, Ontario, Canada
Rep Power: 0 isn't it only the low-end torque that SRIs kill? isn't that why the AT shifts down since the tranny feels it needs more torque to go up the hill without bogging down the engine? i dunno... i have no clue hehe
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From: Milwaukee, Wisconsin, US
Rep Power: 400 Originally posted by Bartkat
Nope. It really does downshift at lower speeds. I have a test hill where I do runs both ways and repeat. I've also driven each SRI for at least 5000 miles. What I'm saying is that if the HP gain is all on the top end, it really isn't doing me any good in routine highway driving. The only other thing I can think of is that the big air filters are giving a different MAP so the ECU is seeing some sort of difference and trying to adjust by shifting.
I guess I'd have to look at how the HP and torque curves change with these intakes. I'm thnking there may be less torque or the peak torque RPM is changed. Horsepower without torque really doesn't mean a whole lot, I think.
Anyhow I put in the K&N stock replacement with the hose and slipped a OBX SRI tube over the hose so it looks purty. Took it out to the hill and made two runs and it didn't downshift, and maintained speed (I always do this test in cruse control at 70 MPH).
Nope. It really does downshift at lower speeds. I have a test hill where I do runs both ways and repeat. I've also driven each SRI for at least 5000 miles. What I'm saying is that if the HP gain is all on the top end, it really isn't doing me any good in routine highway driving. The only other thing I can think of is that the big air filters are giving a different MAP so the ECU is seeing some sort of difference and trying to adjust by shifting.
I guess I'd have to look at how the HP and torque curves change with these intakes. I'm thnking there may be less torque or the peak torque RPM is changed. Horsepower without torque really doesn't mean a whole lot, I think.
Anyhow I put in the K&N stock replacement with the hose and slipped a OBX SRI tube over the hose so it looks purty. Took it out to the hill and made two runs and it didn't downshift, and maintained speed (I always do this test in cruse control at 70 MPH).
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Rep Power: 0 I'm thinking back to a Pinto I had. Edlebrock had a dual port intake manifold that was supposed to be good HP for it. Now that I've thought about it, I had the same early downshiting with it. I think the whole thing relates to changes in manifold vaccuum or MAP. I'll do some research on that.
Thanks for helping me think on it.
Actually the early shifting helps the car to be more responsice, like arond town, more peppy when it kicks down, and of course you can somewhat control that by throttle position. OTOH at highway speeds it can be a nuisance and I'm sure it has a small negative effect on gas mileage.
Thanks for helping me think on it.
Actually the early shifting helps the car to be more responsice, like arond town, more peppy when it kicks down, and of course you can somewhat control that by throttle position. OTOH at highway speeds it can be a nuisance and I'm sure it has a small negative effect on gas mileage.
Last edited by Bartkat; Apr 9, 2003 at 09:05 AM.
hehe ... staying practically stock now? Premium Member
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Rep Power: 0 Yeah. I'm just going to run with the stock airbox and K&N OEM replacement filter, but with a hose instead of the stock resonator. Gotta see how that does on the next big trip, next month. When I go to Cleveland it's about 1500 miles round trip.
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Rep Power: 0 But doesn't the resonator factor in to the low-end torque equation? ie, longer tubing = better for low-end? You're planning to get rid of your FIPK? So far i'm happy with mine... can you take a pic of your enginebay? I'm curious to how your setup loooks like 
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Rep Power: 0 Can't post a bigger picture. You can copy that one and blow it up. You can't see the hose anyway because it's inside the polished tube. It's almost as quiet as stock. No varooom sounds like the SRI's. The hose is a radiator type reinforced rubber hose of the same OD as the ID of the air inlet on the filter box. I got it that size so it would be a tight slip fit into that opening. I think it's 2 1/2 or 2 3/8 OD hose.
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Rep Power: 0 Originally posted by txtadik
soooo you feel any difference between your "Bartkat" (is it CARB excempt? lol!) intake and the other SRIs you've tried out?
soooo you feel any difference between your "Bartkat" (is it CARB excempt? lol!) intake and the other SRIs you've tried out?
It's got to be better than stock though because now I have this nice polished tube insttead of that ugly old OEM intake resonator.
I think the downshift thing is all about MAP. Or maybe the people that make SRI's think they can fool you into thinking performance is better by making your car more zippy with lower gears engaged.
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Rep Power: 0 Originally posted by S2000man01
lol. dear Lord bartkat, use the EDIT button!
lol. dear Lord bartkat, use the EDIT button!
Use your scroll button.
