To "de" Or Not To Be

[ale89se]

I HAVE AN 1989 COUPE SINGLE CAM AND I WAS WONDERING IF THE DUAL CAM ENGINE, FROM AN 91-98, COULD BE SWAPPED IN JUST LIKE THE SR20. THANK YOU FOR YOUR HELP

[WDRacing]

You'll find better answers here......

[cow]

You have to have a DE ECU, PS lines (if you have PS) and AC lines. I think that's all. Pretty simple swap from what I understand.

[RedShred]

anything is possible. But good power can be made from the SOHC. The SOHC gives up some HP and TQ in stock form, but that can be regained with appropriate mods. You dont have to spend gobs of cash either...If your rebuilding yoru engine, have some higher compression pistons put in... 10:1 works for me... have the Head ported and a decent Cam installed. Once its all together, Use a logical exhaust and a means to get cool air into the engine.Look around for a used engine from somebody's conversion and rebuild that...

Swapping to a DE is more logical to me than an SR conversion. Atleast you can legally smog a DE. There are several directions you can go.

Ultimately, the choice is yours. I like being different and having a fast SOHC.

[TomsMR2]

^ if you did all those mods on a DE, you'd have a faster car. if you're gonna mod something, you might as well start out with the most hp on the best engine possible.. which is the DE (sr20's not included, because of SMOG etc etc).

[SPIRO]

Its all a matter of preference. I personal prefer the single cam, theres more room in the head for removing of material port and polishing ect, it is easier to tune correctly, fewer moving parts, and is capable of making just as much power as a DOHC. There is also a fairly cheap turbo kit available for the SOHC check out http://www.realnissan.com for all your single cam needs. They specialize in KA24E performance. I think its pointless to swap a perfectly good E for a DE, its just a waste of money in my opinion. Well good luck with whatever you end up doing . The DE fits right in.

[RedShred]

^ if you did all those mods on a DE, you'd have a faster car. if you're gonna mod something, you might as well start out with the most hp on the best engine possible..

I disagree bud. Seems like alot of trouble for 15 more hp base along with another cam to buy, more valves blah blah. But I drive a nicely modified SOHC and know I make plenty of power for my money without the added benefit of the 4 extra valves.

Just an opinion.

[Jays90240SX]

Yeah, it's interesting, I had just no Power streering, no AC an d I got 119.7whp and 138.9 ft. lbs of torque from a SOHC.

I KNOW that with little things like removal of the butterflyes, port/polish head and intake manifold, cam, higher compression pistons, nice header and exhaust I can achieve some great power, and I am almost 100% sure it would be at par with the DE with the same mods.

Actually, more since you need some cash to buy the DE, the wiring harness, gauge cluster and all that.

I think the SOHC is awesome, no need for a DOHC!

[TomsMR2]

16v > 12v. DOHC > SOHC.

16v's can offer more top end power by virtue of design.. they just simply flow better.

[nlzmo400r]

unless ur SOHC is shot to shiz, or has 9,ooo,ooo,oook on it, then just keep hte SOHC, if its that screwed up , go for DOHC if u HAVE to replace it, cause they're gonna cost you damn near the same

[TomsMR2]

ill rephrase. if you have a sohc, keep it. if you have a dohc, keep it. while the dohc IS a better platform to start with, the sohc isnt *that* far behind... regardless, if you had a choice of the sohc or dohc, and each cost the same.. the dohc is the better choice.

[SPIRO]

Quote »16v > 12v. DOHC > SOHC. [/quote]

That is why it has 15 more hp STOCK, but there is more room in a SOHC head because of the single cam placed in the middle for porting and polishing and the exhaust valves can be enlarged. Put an unlimited amount of money in both heads and in the end the SOHC should have more air flow.

Agian it doesnt really matter but i would rather start with a SOHC. Its really an endless battle so i'll get out of this post on this note .

[spec-v5150]

Dont waste your time UNLESS 1)your SOHC blew2)you got the DOHC for DIRT cheap. I WAS in the process of this swap just this weekend. But the headache of removing an engine isnt worth an extra cam and 15 HP in my eyes. Not when there are turbo kits and DIY options for both

[TomsMR2]

there is more room in a SOHC head because of the single cam placed in the middle for porting and polishing and the exhaust valves can be enlarged. Put an unlimited amount of money in both heads and in the end the SOHC should have more air flow.

im sure you can port both engines to unstreetable levels. just because a head flows more doesnt mean its better. if you over-port, you drastically lose velocity and the head is crapped. 2 smaller valves can flow just as much air as 1 big valve, but can do it more efficiently, at a higher constant velocity.

you can stick a intake manifold with 2 inch long runners and port the hell out of a DE head and get so much flow its obsurd.. the thing is, you'll never ever need that much flow. the DE head is better technically.

... but like people have said, its not worth swapping unless its basically free.

[sil80drifter]

spiro, I am a SOHC fan myself, in fact i am building a KA-ET this summer, but how do you explain one big exhaust valve flowing more than two medium sized ones? Did you do measurments on the head? Did you find the maximum size of the DOHC exhaust valves possible? SOHC valves possible? Car makers started making DOHC engines for a reason. And the most powerul Nissan cars are DOHC for that same reason. I love my SOHC KA, and I will defend it against claims like "it's a crude truck engine uncapable of power, etc" but the DOHC KA's only "flaw" is that it's a little harder to work on. Given a fresh SOHC/DOHC choice from the start, I would go with DOHC, because it's always better to have the cam lift two smaller valves than one huge one. Same logic works for not making 2 huge piston engines, but making smaller 4 piston ones. This is just an example, don't try to catch me on the wording, but a 2 liter 4 cyl is better than a 2 liter 2 cyl. And a 2 liter 6 cyl is even better. Which is why the RB20DET is far superior to the SR20DET. The mass of the piston decides how fast the engine can be revved. Likewise, the mass of the valve decides how fast it can be lifted/lowered with a certain force from the cam. Hence a DOHC will not be outflowed by an SOHC with the same head size. In fact, at best they will flow at the same rate. Because the area of a circle you can fit into a rectangle will be smaller than the are of two circles being fit into that same rectangle, which is smaller yet than the area of (huge number to show my point) 1000 circles being fit into that same area. You see what I mean?

sil80

[SPIRO]

I never said that one exhaust port was better than the two I just figured that the more room for porting made up for the single exhaust valve but you are right TomsMR2 thank you for your reply.

[RedShred]

Good thing this guy didnt ask about a VG / RB / SR swap... LOL This thread would be enormous.

Hmmmm although a VG30DETT would be nice. Or a whole z32 with one it would be cool too. Anybody want to trade a nice RHS13 for a Z32 TT ? lol.

ale89se,Do what you can afford. You can see very good arguements from both camps.

[spec-v5150]

Good thing this guy didnt ask about a VG / RB / SR swap... LOL This thread would be enormous.

Hmmmm although a VG30DETT would be nice. Or a whole z32 with one it would be cool too. Anybody want to trade a nice RHS13 for a Z32 TT ? lol.

ale89se,Do what you can afford. You can see very good arguements from both camps.

I LOVE z32's. There is an NA by me for cheap. I was searching to see what kind of power can be made out of that beast. I was thinking get the car, do a rebuild, then throw a 100 shot on there. I just want a z32 damnit but I love not making a car payment

[RedShred]

I'm still paying for my engine, lol. Bought the car for 215 and am at about 5k in engine and stuff. 1600 to go. Almost there.

say it with me.... You should of gotten an SR... You should of gotten an SR

I think Stillen makes loads of stuff for the VG. I think a Pearl Z32 without any wings on standard issue aluminum wheels is one of Nissan's finest looking cars, next to an R34 of course. But Skylines are pipe dreams for a man with my income, lol.

[TomsMR2]

i think z32's look alot better than skylines.. im not into the whole fast-famil-car look..

theres one at a dealer locally (na) for like 6K.. the NA's are actually pretty affordable