DOHC vs. SOHC

[cleancut240sx]

OK, I am pissed. lately weve been having meets in the south jersey area. we just started 2 weeks ago. we have 5 to 6 240s. most of us have 91 and up. but there is this one guy that has a 89 240sx. and everytime he races us, that car always wins by 2 cars. isnt dohc 155hp faster than a sohc 140hp.

I confess all of our dohcs are pretty much stock but in great condition. All he has is headers and an intake. and like most us know. those mods dont do much to the car.

I found out that sohcs have a lighter flywheel compared to the dohcs and the engine is more lighter. but still, dohcs have 155hp. most of us are a little pissed behind his back. cause we have the dohc engine, can anyone justify this. and yes we all have 5 speeds and know how to drive. most of us  owned 240s over 3 years.

[sykikchimp]

maybe you just think your a good driver.. &nbsp; <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/lookaround.gif" border="0" valign="absmiddle" alt=':look:'>

[cleancut240sx]

i am 28. been driving a stick shift since i was 17. and the 3 others guys who have dohcs raced this guy and lose by a car or more etc. being a good driver isnt even a question.

[Potatoskins02]

well the HEADER (just one) can make a difference. If i'm not mistaken it is supposed to add a good amount of power... the guy may also be getting a whole lot better traction than your cars...... i really don't know how to answer this. All i can give are guess's

[sykikchimp]

remember, old cars can be in many varying states of tune.. &nbsp;I believed my car to be running Great! &nbsp;got her dyno'd and had 122hp at the wheels.. &nbsp;I was like WTF?> &nbsp;If his is runing better than yours, blus he has headers and intake.. &nbsp;he would definately have a power advantage.

If you REALLY want to know if it's the driver, ask him to drive your car, and you drive his in a race.. &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

[whateverjames]

sounds strange, but i believe it. i've beaten four DOHC 240SX's with my 90. i talked to each of the drivers afterwards and each of them had similar mods at the time, except one. i personally believe the horsepower figures are wrong on one or the other because for 15 horsepower there is hardly any difference from what i seen. but oh how i wish i had the DOHC &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'> &nbsp;turbo kits would be easier to find.

[nismoryde22]

well i have heard that many 91 and up owners swap a 89-90 stock flywheel into their cars because it is in fact lighter. but i dont know if that contributes to the car being that much faster.

[azian21485]

a lighter flywheel won't make ur car lighter...it'll make ur car rev faster putting u ur power range faster..increasing acceleration (which is probably wat's killing u..or he has adjusted cams or something he isn't telling u guys about)...but dat also means ur revs drop faster so if u suck at driving(not saying anyone does..juss an example) ur revs will drop out of ur optimal power range and u can get slower times

[logo20]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">..or he has adjusted cams or something he isn't telling u guys about)...</td></tr></table><span id='postcolor'>

cams and headers together can increase quiet a few horses. &nbsp;how much lighter is the flywheel in sohc? &nbsp;like two pounds, then the difference would be minimum. &nbsp;

I don't know any 240sx owners. &nbsp;anyone from houston wanna race me? &nbsp;I have a 89 240sx.

[Nismo241]

The only way to adjust your cam is to have adjustable cam gears...but again a small gain if any. &nbsp;In my SOHC I've raced three S13 dual cams at the track two of them have I/H/E and the other just intake. &nbsp;The two with I/H/E ran [email protected], I ran a [email protected] &nbsp;The other one with just intake ran a [email protected] to my [email protected], yes I know driving plays an important role but look at the MPH, that tells hp more or less. &nbsp;I've street raced with an S14 with intake and exhaust and beat him by about 2.5 cars, and raced another 92 coupe with intake and exhaust and beat him by about 2.5 cars as well. &nbsp;I think that hp numbers are coreect but I think the more important factor is looked over...the power curve itself, I think that the SOHC has a wider power curve than the DOHC which is why they are a little quicker.

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ Nov. 12 2002,11:45)</td></tr><tr><td id="QUOTE">remember, old cars can be in many varying states of tune.. I believed my car to be running Great! got her dyno'd and had 122hp at the wheels.. I was like WTF?> If his is runing better than yours, blus he has headers and intake.. he would definately have a power advantage.</td></tr></table><span id='postcolor'>
Heheh.... and my S14 did 142.6 rwhp (152.4 ft-lbs) (http://members.aol.com/a7r/dynochart240.jpg)way back on 8/5/2001, but seems to be pulling a bit harder now that it's at 135k miles :-D

if his car was built on a wednesday then you guys are just plain screwed :-P

[cleancut240sx]

wait wait, so most of you are saying our dohcs are slower than sohcs. our 155 hp doesnt meant anything, no improvement from a 140hp?<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>?? not many owners know about this. and yes we are sure all he has done is headers and intake.

[SIEKER]

were you racing from a stop or rolling?

[cleancut240sx]

from a stop of course.

[drifterx]

i have an intake and exhuast and i beat Loco's DOHC stock.....
we both have the same amount of miles on the car
i have a 90 and he has a 93
i dont get it either but i dont beat him that much.... it is barely noticable
but i do notice once we go over 100 mph he seems to go a little faster till we hit that 118 mph limiter

suspension, tires, driver, clutch does matter in a course

[AKADriver]

go to a real dragstrip, get timeslips and post 'em. &nbsp;that'll tell all.

On average, the DOHC is faster. &nbsp;On average. &nbsp;That does not mean every DOHC will beat every SOHC. &nbsp;Once you modify that all goes out the window anyway.

15hp is not much to stress about.

[s14 RL]

Also it's not necessarily a 15hp difference to the wheels. &nbsp;There's a lot of variables that come into play...tires, clutch, engine condition, level of modification of engine, etc. &nbsp;Next time take a closer look at what the SOHC guy has...also ask to drive it around the block...that in itself can tell you a lot as to how he's beating you.

[toddnappi]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (cleancut240sx @ Nov. 13 2002,11:18)</td></tr><tr><td id="QUOTE">OK, I am pissed. lately weve been having meets in the south jersey area. we just started 2 weeks ago. we have 5 to 6 240s. most of us have 91 and up. but there is this one guy that has a 89 240sx. and everytime he races us, that car always wins by 2 cars. isnt dohc 155hp faster than a sohc 140hp.

I confess all of our dohcs are pretty much stock but in great condition. All he has is headers and an intake. and like most us know. those mods dont do much to the car.

I found out that sohcs have a lighter flywheel compared to the dohcs and the engine is more lighter. but still, dohcs have 155hp. most of us are a little pissed behind his back. cause we have the dohc engine, can anyone justify this. and yes we all have 5 speeds and know how to drive. most of us owned 240s over 3 years.</td></tr></table><span id='postcolor'>
hey where you been meeting in SJ? I'm in W. Berlin right outside of Vorhees. I'm not into racing just chillen but it would be cool to stop by. &nbsp;hit me back sometime [email protected] or pm me see ya

[KiDyNomiTe]

Easiest way, is first dyno the cars, then get some random person to drive a 89-90 and a 91-94. Subtract out the R/Ts and then you have a 50-75% correct answer.

All this talk about SOHCs is making me nto outlaw the 89-90 in my choice for cars.

[OFF TOPIC]
Anyone on Zilvia have a turbo SOHC, I know some on FA does, and I know realnissan.com sells an SOHC kit, but does anyone else sell one, or anyone else know about the realnissan one.
[/OFF TOPIC]

[Sr2O-det]

Strange i beat this 97 240sx with my 89 141000 miles. And i just got intake and exshaust.

[West]

Anyone want to fix my clutch in my SOHC so I can race it against my DOHC and get a stock for stock race.

<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

[shawn_16]

so, the sohc flywheels are swappable with the dohcs correct?
hmm.. might have to go junkyard shopping...

[stil bil]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (WeST @ Nov. 15 2002,02:20)</td></tr><tr><td id="QUOTE">Anyone want to fix my clutch in my SOHC so I can race it against my DOHC and get a stock for stock race.

<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'></td></tr></table><span id='postcolor'>
ill fix your clutch if you let me have your car!! <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/devil.gif" border="0" valign="absmiddle" alt=':devil:'>

[MyFirst240SX]

I hardly ever see many places to get SOHC turbo kits i have proubly about 5. &nbsp;The big name company's don't want to touch it but are little guys that do.

sean

[Ni5mo180SX]

While driving my 90' 240SX I cant quite recall ever losing to a DOHC 240. I had raced a couple other S13s and 14s with comparable mods.

[misnomer]

Heh, before this whole discussion on which of your cars is actually faster, as somebody already suggested, swap cars and run. The driver has more of an impact on a race than pretty much any other factor. That aside, my '89 SOHC was no match for my '92 DOHC. But. . . as everybody's sayin'. . . his might have been built on a Wednesday ;-)

[240Stilo]

Nobody has mentioned anything about an LSD being present. Wouldn't that make a difference in the take off? &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/dozingoff.gif" border="0" valign="absmiddle" alt=':zzz:'>

[misnomer]

iirc, an LSD wasn't an option on the '89 and '90 models. . . Can anybody prove or disprove?

[wraith]

You never know, the guy who beat you might be more willing to push his car to its limits without any regard to hurting his engine. I've raced a couple of friends of mine, and if I was willing to push my car as hard as they're willing to, I would have done better. - But since my 240SX is my daily driver, I can't afford to f$ck it up just to win one race....

Wraith
1996 240SX-SE

[Loren]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (cleancut240sx @ Nov. 13 2002,10:25)</td></tr><tr><td id="QUOTE">i am 28. been driving a stick shift since i was 17. and the 3 others guys who have dohcs raced this guy and lose by a car or more etc. being a good driver isnt even a question.</td></tr></table><span id='postcolor'>
some people never learn how to drive.. actually in my experience, around half of the people who drive 5spd cars never learn how to shift right.. im talking just for putting around town, much less racing. Also he might have better traction than you (good tyres coupled with good driving vs. bad tires and bad driving could easily make up for 15hp at the fly) your talking about 10+yr old cars, as engines wear they lose power, if his is in better tune than yours it could definetly narrow down the 15hp difference.. With his mods in a sohc vs a stock dohc, I'd say your about even give or take a couple horsepower (presuming your cars are both in the same state of tune).... Or he could just have NAWZ and have it hidden in his passenger seat with the activation button on his stereo like Vin Diesel.

[DSC]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (wraith @ Nov. 18 2002,7:42)</td></tr><tr><td id="QUOTE">You never know, the guy who beat you might be more willing to push his car to its limits without any regard to hurting his engine. I've raced a couple of friends of mine, and if I was willing to push my car as hard as they're willing to, I would have done better. - But since my 240SX is my daily driver, I can't afford to f$ck it up just to win one race....

Wraith
1996 240SX-SE</td></tr></table><span id='postcolor'>
I don't push my engine to its limits because it doens't make any power there. Sure my foot is all the way down, so the engine is at its limit of gaining speed, but I don't take it past redline. &nbsp;Knowing your shift points is pretty valuable. Only thing people push to its limits I guess would be the tranny...just how much do you want to hurt your tranny for .01 sec?