How much power can the RT4WD take?

I'm interested in picking up a RT4WD wagon to do a DOHC ZC swap in, but being a forced induction junkie I'd want to boost it. Anyone here done something similar? Anyone know what the limits for the RT4WD system is? I figure I'd try not to go over the 200hp mark, which wouldn't be too hard using a small 14b or 16b T25 turbo off of a Mitsubishi Eclipse/Eagle Talon/Plymouth Laser and 7lbs of boost or less. I get the feeling that the 4WD wouldn't be able to handle the stress of that much power... but it's an idea that I've gotten a lot more interested in. It would be a much cheaper and less labor intensive and more practical swap, at least in the near future, than going with my original plan of a B18 LS-VTEC turbo swap into a 2WD wagon.


  • JDMshuttleJDMshuttle Senior Wagonist
    the most i have seen is 300 + but that was pushing a dohc zc and the stock trans
  • HaydzHaydz Moderator
    Theres not enough people doing serious HP/torque increases to pick any trends but at the same time there havn't been any major horror stories.

    At a guess (and thats all it is) you will be able to sit around/under the 200hp mark safely but i would strongly reccomend supporting modifications..

    The thing about the RT4WD system is that it uses a viscous coupler, so the power transfer isn't instantaneous - therefore puts less stress on the system as the power is transferred. If it were mechanical i.e. LOCK, BANG... then i'd be worried.

    Keep in mind that the ammount of power that is sent to the rear is directly proportional to the ammount of slippage in the front - so if you revv the snot out of the engine and drop the clutch your bound to get alot of power transfer to the rear, even more so in slippery conditions.

    I have an RTi running a DOHC ZC and i love it, good luck! :D
  • i also have an rt dohc zc n my 88. i love it too. i also want to boost my setup. what fuel management are you going to use? that and timing is the only things keeping me from starting this project. i drive the shit out of my car and the rt system holds up well. i also off-road in her. i think the trans will do fine with about 200hp, but thats just my opinion.
  • 4wdwagon4wdwagon Band Wagon
    I had my wagon boosted with a basic HMT 14b setup on the stock A6. It was fun, but I noticed that gradually the rear wheels took longer to engage, that the viscous coupling got accelerated wear.

    I ended up puttting the wagon back to stockish. The 20-22mpg on premium was a killer, and while the car was fun to drive, it was not a true performance car. The 4wd wagon, especially the 90-91's with automatic seatbelts, are just about the heaviest civics made. The rt4wd offers no performance driving advantage, imo. It just takes too long for the rear wheels to engage to be of any use except climbing hills in the snow, ice, or mud. The cable operated shifter feels like crap, and the gap between 2nd and 3rd is too big. Just my opinion.

    Here's a vid of my wagon, when it was boosted
  • 4wdwagon4wdwagon Band Wagon
    I just noticed you are in Everson. I'm in Bellingham.

    If it were me, I'd look for a 88-89 2wd wagon. They are the lightest wagons. I'd just do a MPFI swap, and boost the stock d15. When that blows swap a D16z6, a6, y8 in there. If you keep your eyes open, you can sometimes find a crashed integra in the echo or craigslist for $500.
  • HaydzHaydz Moderator
    I've heard a few people say now that it takes too long to engage rear drive, even on Orthia's and CRV's... Thats definately a viscous coupler wear issue because mine is almost instantaneous.

    As for the cable shifter, it does feel sloppy if the adjustment is loose but IMHO it feels better than the solid linkage once its adjusted.

    If you want the lightest wagon, go for an '88 Wagovan/Civic Pro.
  • 4wdwagon4wdwagon Band Wagon
    Here's a vid of another boosted wagon in B'ham
    Leed from HMT.

    You can see the delay in the rear wheels kicking in when he does a little burnout.

    Pacifer you may be right about it being a wear issue. We are going to have to agree to disagree about the cable tranny. Mine is adjusted to Helm manual spec, and feels like garbage in comparison to a normal civic tranny.
  • HaydzHaydz Moderator
    One thing that needs to be said is no matter how well the shifter is adjusted, if the transmission is running crap MTF/ATF then its gonna make the changes feel sloppy. Same goes if the synchros are glazed or shot.
  • RyanRyan Band Wagon
    Yeah, I'm already familiar with Dave Lee's HMT wagon, I used to want to try to buy it off him. I do think it's funny that basically all of their "burnout" videos are done behind CostCo. :lol:

    Yeah, I'm loosing encouragement to doing the DOHC ZC turbo into a RT4WD. I'm getting too afraid that it wouldn't take much to break, especially the viscous coupler. I guess I'll have to go with my original idea of the LS turbo wagon, but I only found out a few days ago how rediculously heavy 90-91 wagons are. My current wagon is an '85 2wd carbuerated, so I'm going to look for an 88-89 2wd. Jesse Hayes told me to just go DOHC ZC turbo whether I'm doing 2wd or 4wd, and that's the route I'll probably go since I need to put money into my primary goal of getting the 240SX project going. Finances have a good chance of putting the whole wagon project on hold though, until I get a 240 done.
  • HaydzHaydz Moderator
    My fully optioned 1990 Shuttle only weighs in at 1120KG with a full tank of gas, its not that heavy.. Little bit of a diet here and there never hurt anyone... ;)
  • TadasTadas Wagonist
    Good day, sorry to bring the old posts back, but I have been looking at boostedbois videos on utube and they make some wicked power (450whp) running 4wd.

    I want to build a big-dick-turbo d16 one day so this is a serious question.

    Maybe if we use boost by gear it would save our transmission?

    The only reason I am planing to stick with d16z6 engines forever is because I want to keep the rt4wd.
  • bkmc24bkmc24 Senior Wagonist
    VIPWryann had a 350+ hp one. It's on here and YouTube.
  • Im curious as to how much petrol you guys go through. I get about 18MPG which is about 131 miles out of 40, give or take a few miles depending on the fuel prices. Im just wondering what you guys get.I do about a 40/60 spilt between rural/urban.
  • I get on average with the A/C in warm conditions, 28-30mpg. Thats probably 40/60 like yourself. I have seen a consistent 40-42mpg on long highway trips w/o AC on. Of course, I am completely stock.
  • I know that my wagon usually does 10L/100km or in U.S. terms 22-24 mpg.
  • according to people on the facebook group, the wagon viscous coupler and diff can handle 1300+ hp and apparently several 7 second hondas are running wagon drive train stuff. I've always been really surprised that people are always worried that the wagon can't take much power. It seems well known that is much stronger than more modern awd honda components.

    Also, my wagon gets 29mpg highway when switched over to 2WD but only 17mpg in 4WD and city driving. I have a DOHC ZC with JRS (hence the low city mileage)
  • Actually I am confused with this new craze of AWD hondas running wagon VCs. It wasn't too many years ago that ppl were burning up their VCs with too much power. Call me confused....but they are certainly raising the prices of parts! Have you all see what they want for a RT drive train now a days on eBay?
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