how high have you modified your car to rev?
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how high have you modified your car to rev?
Anyone here modified their D17 to rev higher than normal redline? What kind of success have you had?
I ask this, because I have read that the K20A2 tends to break a rod when revved to the 8600rpm redline with the hondata flash.
Wonder if that's happened to any K20A2 owners yet.
I ask this, because I have read that the K20A2 tends to break a rod when revved to the 8600rpm redline with the hondata flash.
Wonder if that's happened to any K20A2 owners yet. 
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or were you referring to the swapped vics?
or were you referring to the swapped vics?
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Rep Power: 400 No i was referring to the D17. I wanted to know if anyone has had success with revving the D17 beyond the 6800rpm redline. I asked because I heard of the RSX problem.
So I'm curious what kind of success people have had with the D17. Most hondas can be revved safely about 500-600 rpm over stock, but with the RSX this seems to not be the case without upgrading your rods, rod bolts, etc.
So I'm curious what kind of success people have had with the D17. Most hondas can be revved safely about 500-600 rpm over stock, but with the RSX this seems to not be the case without upgrading your rods, rod bolts, etc.
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Rep Power: 374 I think the redline on a d17a2 is 7200 before the limiter kicks in. I'm only guestimating that number by watching my tach when messing around with it.
i know someone who put a chip in their gsr motor to rev up to 9k he also told me he blew his engine twice. Only because he kept revving. He still has the chip and a new engine(cause he can do engine by himeself) and now he doesnt rev up high only when he needs to. he told me his internals were stock just the chip to make it rev higher. I was thinking of investing in that, but through this guys experience I felt way safer with my nitrous.
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Rep Power: 0 never heard of it unless you are running like a stand alone system...my buddy has a crx b16 swap w/fully built internals...w/nitrous and a super computer with no rev rev limiter and no speed governere...i think you can do that to a d17 with the proper computer system
Originally Posted by JDm7thGen
never heard of it unless you are running like a stand alone system...my buddy has a crx b16 swap w/fully built internals...w/nitrous and a super computer with no rev rev limiter and no speed governere...i think you can do that to a d17 with the proper computer system
Originally Posted by blouisgod
I think the redline on a d17a2 is 7200 before the limiter kicks in. I'm only guestimating that number by watching my tach when messing around with it.
EX's fuel cut off is 6900-7000 (according to my profec e-01), and a DX/LX's is 6800 (according to drivetofast's autometer tach) ... who knows, maybe they're the same though
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Rep Power: 0 ive acidentally mis-shifted and seen the needle on the tach hit somewhere around 8500, but it wasnt there long. the car was fine but i dont think the d17 would last long revving that high all the time.
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Originally Posted by stroked_monkey
ive acidentally mis-shifted and seen the needle on the tach hit somewhere around 8500, but it wasnt there long. the car was fine but i dont think the d17 would last long revving that high all the time.
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Originally Posted by aznboysrfr
I've never heard of a k20a2 having valve float let alone breaking a rod at 8600 rpms ... k20a3's on the other hand .....
usually when the rod fails on the K20A2, it's when the piston is at TDC during the exhaust stroke, since this is when the rod and rod bolts are under the most stress. believe it or not, increasing your redline from say 8200 to 8600 causes an exponential amount more stress to your rods. it has to do with rod/piston acceleration/deceleration more than anything.
--anyways, so no one has really increased the redline of their D17? I thought a few members here had the ECU. I was hoping to find out if anyone has successfully done it because I'm curious what you're running and whether or not your stock internals have held up, etc. just trying to learn more about the limits of the car.
anyone?? i swear some members here had aftermarket ECUs!!
Last edited by S2000man01; Feb 23, 2005 at 05:58 PM.
Originally Posted by S2000man01
yeah, the K20A2 will eventually break a rod or rod bolt if you continue to rev it to 8600 a lot, or race it a lot. If you go to 8600 with the hondata flash and stock rods, you'll be fine as long as you do it only when you absolutely have to. but race the car every day, several times a day, you're going to have a rod fail soon. in fact, according to a well known dyno shop owner, it's become so common place at the track for people who race their type S with the 8600rpm redline, they keep extra sets of stock rods with them at all times. lol
usually when the rod fails on the K20A2, it's when the piston is at TDC during the exhaust stroke, since this is when the rod and rod bolts are under the most stress. believe it or not, increasing your redline from say 8200 to 8600 causes an exponential amount more stress to your rods. it has to do with rod/piston acceleration/deceleration more than anything.
--anyways, so no one has really increased the redline of their D17? I thought a few members here had the ECU. I was hoping to find out if anyone has successfully done it because I'm curious what you're running and whether or not your stock internals have held up, etc. just trying to learn more about the limits of the car.
anyone?? i swear some members here had aftermarket ECUs!!
usually when the rod fails on the K20A2, it's when the piston is at TDC during the exhaust stroke, since this is when the rod and rod bolts are under the most stress. believe it or not, increasing your redline from say 8200 to 8600 causes an exponential amount more stress to your rods. it has to do with rod/piston acceleration/deceleration more than anything.
--anyways, so no one has really increased the redline of their D17? I thought a few members here had the ECU. I was hoping to find out if anyone has successfully done it because I'm curious what you're running and whether or not your stock internals have held up, etc. just trying to learn more about the limits of the car.
anyone?? i swear some members here had aftermarket ECUs!!
I dunno ... tons and tons of people on clubrsx have hondata #4 and if anything, they're gonna experience valve float (~9300 rpms, as stated by Hondata) before they experience broken rods. I know that the stress on your valve springs increase exponentially, but I haven't heard of the same for the rods (though I wouldn't be surprised if it did) ... but that could go for anything.
of course if you do nothing but race your motor, you're gonna break something. I'm not arguing with you, but I'm just noting that I have never, ever read anything about anybody breaking rods due to an 8600 rpm fuel cutoff on clubrsx (and I'm there very often)
edit: oh yeah ... someone posted a dyno sheet of a prototyped d17 with aem's new ems ... it went up to 7500 rpms
http://forum.aempower.com/bbs/download.php?id=3081 (note to people: mustang dyno's are typically lower than a dynapak and dynojet)
Last edited by aznboysrfr; Feb 23, 2005 at 06:17 PM.
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Originally Posted by blouisgod
I think the redline on a d17a2 is 7200 before the limiter kicks in. I'm only guestimating that number by watching my tach when messing around with it.
7200?!?!? Fuel cut happens at 6950 rpm, I Have a pic of my Vafc2 showing it also.
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Rep Power: 400 hey good find on the dyno! cool, so that's one person. anyone else using aem ems? i wonder if he's had problems with the car at the higher redline?
oh and here's the post about the K20A2 rods breaking.
here was the question
and the answer. (this is UL, the guy who owns the dyno shop where hondata does their R&D and is personal friends with the hondata founders/owners)
so from the sound of it, racing now and then won't hurt a K20A2 spinning to 8600rpm, but if you drive it like you stole it, you're gonna snap a rod. 
oh and here's the post about the K20A2 rods breaking.
here was the question
could you help out my understanding on engine dynamics and explain why the faster revs would more likely lead to conrod failure, rather than something involving the piston directly? Is it simply that the extra distance the rod has to travel, and the therefore higher accelerations is experiences, are too much for the rod material to handle? If so, are there stronger aftermarket rods that could be put in to compensate for this?
High rpm stresses on the bottom end are usually the worst at the top of the exhaust stroke. The piston wants to continue upward while the crank is just starting back down. The rod, rod bolts and wrist pin are in tremendous tension at this point (as is the wrist pin boss on the piston, but this is rarely the first failure point). Its worst on the exhaust stroke because there is no attendant gas pressure (as on the compression stroke) to help slow the piston. This tension is a function of of the piston speed and the rpm. Both are important because the deceleration of the piston is where the highest stresses are. Its usually the rod beam, or the rod bolts that fail first on Honda engines, although it isn't _always_ that way.
We've generally found that most Honda engines are capable of handling 400-500 rpm over stock on a regular basis for street driving. However, there are prices to pay. On the regular F20C, exceeding 9000 rpm on any regular basis will cause valve retainer problems (as we've seen on some race cars which were never taken above 9300 rpm and no overrevs). But the bottom end is fine. On K20A2 engines, cars that reach 8600 rpm under racing conditions will break a rod within a couple of races - we've seen it happen to three separate race teams such that it has become a defacto standard to keep stock rod K-motors under 8500 rpm for racing purposes.
As I said, I think an F22 would live with revs to 9000 rpm, but sooner or later you're going to break something. For street and occasional track use, 8500 rpm is generally accepted as safe. For heavy race use, as I said, we won't exceed 8200 rpm until someone starts beating us, and then we'll do it with much trepidation.
We've generally found that most Honda engines are capable of handling 400-500 rpm over stock on a regular basis for street driving. However, there are prices to pay. On the regular F20C, exceeding 9000 rpm on any regular basis will cause valve retainer problems (as we've seen on some race cars which were never taken above 9300 rpm and no overrevs). But the bottom end is fine. On K20A2 engines, cars that reach 8600 rpm under racing conditions will break a rod within a couple of races - we've seen it happen to three separate race teams such that it has become a defacto standard to keep stock rod K-motors under 8500 rpm for racing purposes.
As I said, I think an F22 would live with revs to 9000 rpm, but sooner or later you're going to break something. For street and occasional track use, 8500 rpm is generally accepted as safe. For heavy race use, as I said, we won't exceed 8200 rpm until someone starts beating us, and then we'll do it with much trepidation.
Last edited by S2000man01; Feb 23, 2005 at 07:36 PM.
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edit: oh yeah ... someone posted a dyno sheet of a prototyped d17 with aem's new ems ... it went up to 7500 rpms
Did you notice the BIG loss in power after redline?
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well idk about stock internals. i've had a decent turn out with some after market parts. If you would like a suggestion save your money tilleverything is cheaper for our cars. If it ever happens.
Originally Posted by S2000man01
hey good find on the dyno! cool, so that's one person. anyone else using aem ems? i wonder if he's had problems with the car at the higher redline?
oh and here's the post about the K20A2 rods breaking.
here was the question
and the answer. (this is UL, the guy who owns the dyno shop where hondata does their R&D and is personal friends with the hondata founders/owners)
so from the sound of it, racing now and then won't hurt a K20A2 spinning to 8600rpm, but if you drive it like you stole it, you're gonna snap a rod.
oh and here's the post about the K20A2 rods breaking.
here was the question
and the answer. (this is UL, the guy who owns the dyno shop where hondata does their R&D and is personal friends with the hondata founders/owners)
so from the sound of it, racing now and then won't hurt a K20A2 spinning to 8600rpm, but if you drive it like you stole it, you're gonna snap a rod.
well, I have also heard that hitting fuel cut off is many times worse than hitting, say 9000 rpms (a la Derek Stevens of Hondata, iirc)... so it could also be the case that the race teams were scraping the fuel cutoff.
I have also created a thread at clubrsx about broken rods at 8600 rpms ... http://forums.clubrsx.com/showthread.php?t=241590
let's both note that I am NOT trying to start an argument and I am not trying to be offensive (in contrary to other threads that I may participate in
), but I'm just trying to set things clear (because I am also in line for a k20 swap coming up soon ... so this is useful info) Last edited by aznboysrfr; Feb 23, 2005 at 07:44 PM.
hey s2k man, you think my rods will go soon? for a year already I have been driving my car hard always shifting at 7k redline. WIll my rods go soon because of that or only if I chip it to make a higher redline?
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Originally Posted by DIZZLE
7200?!?!? Fuel cut happens at 6950 rpm, I Have a pic of my Vafc2 showing it also.
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Originally Posted by aznboysrfr
interesting ... I think they meant an F20c where it says F22 in the last paragraph ;P
Originally Posted by aznboysrfr
well, I have also heard that hitting fuel cut off is many times worse than hitting, say 9000 rpms (a la Derek Stevens of Hondata, iirc)... so it could also be the case that the race teams were scraping the fuel cutoff.
if you overrev, in the case of the S2000 you have a chance of piston to valve contact, floating valves, or in the case of the RSX and D17, throwing a rod, since the rods are not made to take that kind of stress.
make sense?
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Originally Posted by Civic_RedLine
hey s2k man, you think my rods will go soon? for a year already I have been driving my car hard always shifting at 7k redline. WIll my rods go soon because of that or only if I chip it to make a higher redline?
but i am curious as to their tolerance when you raise the redline, hence my initial question. so far no solid answer. but we got a dyno of a 7500rpm redline so that's good info so far.
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Originally Posted by aznboysrfr
let's both note that I am NOT trying to start an argument and I am not trying to be offensive (in contrary to other threads that I may participate in ), but I'm just trying to set things clear (because I am also in line for a k20 swap coming up soon ... so this is useful info)
), but I'm just trying to set things clear (because I am also in line for a k20 swap coming up soon ... so this is useful info) technical discussions are good for everybody. 
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Rep Power: 424 Well this is first I've heard this. I've never heard anything breaking on the A2 or A, I'm aware of issues with Hondata's redline on the A3 reflash and some serious valvespring issues. There was a batch of early 2002 K20A2s that had similar valvespring issues, but the springs were changed on Honda's end somewhere mid production. I'm not surprised by it, undoubtebly if you exceed what it was intended for, somethings gonna give. Its a relatively well known fact that the K motors are not as overdesigned as the B-series motors were... some of that leads to its lighter weight despite increased displacement and power, but you give up all that metal that put extra strength into those parts. As far as overrunning a D17 redline, I don't see much point given the engine's power curve. I suppose if you could get a bunch more air in it you can raise the redline, but you're probably running short on breath by the time you start hitting 7000 unless you give it larger VTEC lobes and bigger runners to pull air through. I've made some ill timed downshifts on the track before, hit 7500 or so and have never heard a bad noise, but usually I'm hard on the brakes while I do it, so the revs come back down rather quickly.
