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Discussion Starter #1 (Edited)
RPM Limit on FJTs and Vitaras Or all other forged piston guys.

Hey guys. I was wondering how hard everybody was revving the new long i beams. I will be using new stock valves and supertech springs and retainers with a zex 59300 cam. I have a friend revving his eagle/vitara set up to 9100 with the same head stuff i will have but i wasnt sure if that would be too high for a long rod. How high has everyone revved their long rod build?

Thanks guys.

EDIT: Basically i am looking for guys revving their motors with the pistons at the top of the cylinders. Are there any valve float issues? Is there a cam too big for a certain Rpm? Please chime in.
 

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where ever ur engine stops making power... only ur tuner can find that out. no 2 setups are alike.

i assume since ur aftermarket rods are going to use arp rod bolts?
 

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long rods = better rod to stroke ratio = less sidewall load and better ability to rev higher and safer.

but it is pointless to rev to the sun and back if you stop making power at the moon.

pretty much if you make 400 @ 8k, and you make 410-415 @ 9.5k why push the 1,500 RPM and risk something if you only make 10-15 more hp.
 

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Hey guys. I was wondering how hard everybody was revving the new long i beams. I will be using new stock valves and supertech springs and retainers with a zex 59300 cam. I have a friend revving his eagle/vitara set up to 9100 with the same head stuff i will have but i wasnt sure if that would be too high for a long rod. How high has everyone revved their long rod build?

Thanks guys.
Longer rod yields a better r/s ratio (not much but every bit helps). So your new FJT Longrod setup theoretically should make your engine happier at higher rpms.
 

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pretty much if you make 400 @ 8k, and you make 410-415 @ 9.5k why push the 1,500 RPM and risk something if you only make 10-15 more hp.
Easy answer, to take better advantage of the poor D-series gearing options. 1500 extra RPM means your powerband can be 1500 RPM narrower and still get down the track in a hurry.
 

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SilentWrath* & OneCam: umm, what? the d16 has a horrid RS ratio.

too true, thats why i used the word "better" as in better than stock, and also threw in the "not much but every bit helps" disclaimer.

side note: try to imagine the piston speed at 9100rpm in a d16 (1.5?:1 r/s). now that's fast!
 

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yeah im pretty aware of the shitty RS. but im pretty sure longer rods do improve upon the already shitty base we are handed.

and im sorry but for 15whp. I dont see revving that extra 1500 rpm necessary. im pretty sure jeff evans would agree as this is what he does for a living and how he tunes cars. once the curve flattens out, he takes it back a notch.

im sorry but with $10,000+ into my car, 15whp is not worth my $4-$5k engine exploding, let alone my time, blood and sweat.
 

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yeah im pretty aware of the shitty RS. but im pretty sure longer rods do improve upon the already shitty base we are handed.

and im sorry but for 15whp. I dont see revving that extra 1500 rpm necessary. im pretty sure jeff evans would agree as this is what he does for a living and how he tunes cars. once the curve flattens out, he takes it back a notch.

im sorry but with $10,000+ into my car, 15whp is not worth my $4-$5k engine exploding, let alone my time, blood and sweat.
It's not about the 15 whp. It's about your RPM being 1500 RPM higher into your powerband after you shift.

It doesn't matter if you have a tiny turbo and a huge wide powerband. It does matter if you have a large turbo that spools late.

Falling out of boost between gears blows, and extra RPM makes the problem better.

If you aren't racing, probably not worth it. If you are, it makes a HUGE difference.

Side not, Jeff Evans stops adding timing when the tq stops going up and backs it up a few notches. Hugely important factor for tuning. :)
 

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It's not about the 15 whp. It's about your RPM being 1500 RPM higher into your powerband after you shift.

It doesn't matter if you have a tiny turbo and a huge wide powerband. It does matter if you have a large turbo that spools late.

Falling out of boost between gears blows, and extra RPM makes the problem better.

If you aren't racing, probably not worth it. If you are, it makes a HUGE difference.

Side not, Jeff Evans stops adding timing when the tq stops going up and backs it up a few notches. Hugely important factor for tuning. :)

that 1500 rpm is still 1500 rpm whether its for the power or the power band. it still greatly increases your risk of a fail thread getting posted in your vehicles honor. I agree if you're die hard racing and you have the money to blow on another motor when that one toastes then by all means go ahead. but this kid is prolly dailying this car. so stop where the power stops, theres no reason to push it.
 

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what turbo 1st of all?

hes using a bigger cam + springs/retainers, so Id say above stock is good, but I dunno about 9.5k. Its not a b16. Id find where you can shift and not lose a ton of boost, but some, but also keep the motor intact.

If hes using a Super 60, this is a moot point. If hes using a GT35R, Shifty might have something. And I personally am not a big Jeff Evans fan.
 

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the thing i would be concerned with OP, is what way did you install your pistons? if the arrow points towards the crank pulley.. i wouldnt rev em high. the piston pin offset is backwards and it will load up the piston pretty bad.

fjt's response to my asking if there might be any issues installing the pistons toward the crank w/ extended i beams....(i did not mention pin offset so i cant say for sure he was thinking about it, i recently came into that info)
fjt said:
member molecule reported to me that there is a guy in Ohio that is currently our Vitaras and I beams. Hes got 330 something whp right now and no problems woth P2V contact... I dont know what cam he is running but arrows are pointing towards the timing belt.

The only problem i see is in the case of missing a gear and over revving or Valve float.
 

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Discussion Starter #16
we put arrows towards the flywheel and i will be using a gt3076 with an .82 ar exhaust housing. I highly doubt that the turbo will be falling off before 8500rpms but i could be wrong.

This car is simply a race car that i will rarely drive on the street. I also have a 10sec wrx to play with as well. I just wanted to build a cheaper toy so that if something blows apart it wont be as big of a deal. I actually traded a turbo for the civic anyway. When parts break on the subaru it is expensive. When parts on this hatch break no big deal. I broke an axel in my wrx 2 weeks ago that cost me more than this whole engine build. But none of that is the point. I was wanting to hear from someone who is really revving these thing hard. The reason for the rpms isnt to make more power. It as someone earlier said...the rpms that the car will drop to when shifted. I understand that it isnt a good thing to do, rev a car after it isnt making more power but on the track if you are shifting you car out at say 7500 and it falls to 4000 in the next gear you are more than likley out of your powerband. If you revved it to 8500 then you may drop to 5500 rpm and be around peak torque.

I probably could have asked the after market piston guys this question as well as their pistons are at the top of their block.

I need to make a thread about my tranny ideas and see if they are possible or if anyone has tried. Use a stock dx/lx tranny with a 24.5 tire and maybe never leave 3rd. On mfactorys gear calc you would achieve 140+/-mph in 3rd with that tire and 9100rpm. Then you have no lsd options....I am a fan of a welded diff so there you go on that. What do you all think about that. Transzex feel free to comment.
 

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I have the 59300 cam and will be using it in my similar build...I plan on reving to 8500 to keep myself in the best powerband possible.
 

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Easy answer, to take better advantage of the poor D-series gearing options. 1500 extra RPM means your powerband can be 1500 RPM narrower and still get down the track in a hurry.
i do have to agree with you on this. Also yall know that 700whp d16. he revs WAYYY past his peak rpm.10k area, its not the same with everyones setup... so cant say you shouldnt rev past the peak HP without knowing the setup.Also if my HP is still going up 15more whp for an extra 1500rpms im gonna go that extra 1500rpms its what I built the motor for. to race, not be scarred to use it. that sounds like a show car to me not taking it to its full potential on the track.
 

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Discussion Starter #19
The rpm drop is exactly why i was asking the question. I know the motor wont flow that well in those kinds of rpms but it is a nessesary evil in drag racing. Staying in the power....also means not dropping out of power.
 
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