best swap for fuel economy?

[highly responsive]

lets imagine that money isnt an issue.

i currently have the SOHC, and i am looking at swap options. one thing that bothers me about the SR swap, is that i will be getting worse fuel economy than what i get now (from what i have googled), and i will need to run premium gas. which swap should i do if i am most concerned with gas mileage? rb, vq, vg, even CA if its a viable option..... even if its one that i didnt mention, please share it!

[1slowS13]

i'd say what you have right now would get good gas mileage if you drive it good, and would cost less, for obvious reasons.

to tell you the truth, the 240sx isnt really the econobox type.

[MADE]

I just dropped 75.00 for 14 gallons and everyone at the gas station was shocked and pissed. "It took you 10 mins to put $75 in the little ass car!" Oh it was great and will last me about a week.:2f2f:


IMO If you worried about fuel economy don't do they swap yet.


350Z's use VQ3.5 300ZX use VG30's I think.

I have a VQ35 powered maxima as a daily and the gas mileage is good.

[downshift_sideways]

hmmmmmmmmmmmmm

[highly responsive]

vq30 38.3 mpg U.S.

thanks, useful info. im sure thats highway mpg, right?
also, do i swap one of those out of a 350z?

[downshift_sideways]

chyeeaaaa boii

[blackrms13]

thanks, useful info. im sure thats highway mpg, right?
also, do i swap one of those out of a 350z?

Z33 had VQ35...
VQ30 is out of a I30 IIRC

[The ROMAN]

What about an N/A SR? I looked around for mpg figures but couldn't find anything, short of comparing to an SR Sentra. I would assume it'd beat out a KA by quite a bit and they're not too expensive.

BTW fueleconomy.gov lists SOHC KA as 18/24 and DOHC KA as 19/26. SR Sentra is 21/29.

[Z33dori]

just keep the ka...

or buy a honda

[tangch]

One guy that have a vq35 has average of 32mpg. I think their website is nissandoctor.com

[Flybert]

SR's get awesome gas mileage. Stay out of boost and you'll be fine. I remember getting 26-27mpg with a lot of highway. My gas mileage when I had a KA24DE was pretty much the exact same.

[Dutchmalmiss]

I get 26-28mpg(city/highway combined) with my SR and light mods. Owns any other KA mpg from my experience.

[BlckBeautyVTEC]

i get 28 mpg on my KA, but seriously if you want good gas mileage get a civic or corolla

[Camo]

stock ls1 18 city/28 hwy with 345 ponys!!!

[GSXRJJordan]

Yeah I was gonna say LSx also.

The z06, even with a blower/etc (560rwhp) still gets 25mpg+ on the freeway, and around 20mph putzin around town. Keep your foot outta the throttle and away from the high revs.

[Z33dori]

yea most ppl don't realize the less like and idiot you drive the longer you gas will stay in the tank...


really easy concept...

[highly responsive]

thanks for the info on the SR. stay out of boost, makes sense. going into boost would just force more air in, and at the same time increase the fuel being consumed, right?

i already drive like an old man to begin with, and my DD habits wont change with the SR (well maybe not at first :P).

[twistedsymphony]

stock ls1 18 city/28 hwy with 345 ponys!!!

LS1s actually get BETTER milage than that in an S chassis because it weighs about 800lbs less.

the people I've talked to that have one average 32-34MPG on a factory spec motor :eek3d:

and yes 340+hp

oh yeah and it weights pretty much the same as a KA...
... and doesn't cost much more than an SR swap

... it really baffles me why more people don't go LS1

[jrocslider]

http://i52.photobucket.com/albums/g17/mostwantedcamaro/ls1.jpg

a friend of mine had a 600hp C5 Z06. after a tune he was averaging about 31mpg @ 70mph hwy

[The ROMAN]

I would still be interested on opinions on an N/A SR and average mpg of people who have them. I'd pick one up for cheap and have a nice DD/small cone-lot drifter. LS6 is what I'm interested in for the next race car build, though.

[twistedsymphony]

don't bother with LS6

LS6 is just an LS1 with bigger cooling lines in the head, different cams and different tuning. Buying a late model LS1 (2000 or newer) will actually have the same heads at the LS6... the LS1 is about half the price of an LS6 and you have to retune the computer to use in the S chassis anyway.

not to mention the LS6 uses a drive by wire on the throttle which is an enormous headache to adapt to a cable system.

As for the NA SR... IIRC it has LESS power than the KA... honestly if you're all about mileage look into changing your rear end gears you'll get more mileage for your $$ there then with an engine swap. the reason the LSx motors get such great mileage has little to do with their design and everything to do with the fact that they make good torque and they're geared well 6th gear on the T-56 transmission is pretty much just for fuel economy and you can bog around at 1200RPMs all the time. I wouldn't be surprised if an NA SR got worse economy than the KA.

[The ROMAN]

Cool, sounds like good advice on the LS6 (haven't done that much research yet). I'm surprised on the N/A SR though. I figured a newer, more advanced and smaller displacement motor would get up in towards the 30s, especially without the emissions bs. Even my turbo SR does pretty well.

[McCoy]

I would still be interested on opinions on an N/A SR and average mpg of people who have them. I'd pick one up for cheap and have a nice DD/small cone-lot drifter. LS6 is what I'm interested in for the next race car build, though.
I had the SR20DE, then added a T28 to it after about 6 months.

NA I got about 25/31 mpg (town/hwy). With the T28 added I get about 22/33 mpg (town/hwy).

When I was NA I was using the stock KA exhaust and had no other mods. With the T28 I have added cams, exhaust, and a host of other parts that could play into the gas milage differences. I still get better gas milage with the turbo, except on track, than I did NA.

[gripster]

Thanks to those with NA SRs who shared their experiences.

I'm getting around 27 mpg in my stock SOHC, being easy on the throttle, but I'm still looking into the N/A SR swap as well.

I've also looked at changing the rear end.

With stock open diff (4.xx), I get 3400 rpms at between 70-75 mph.

What kind of rpms should i be at with the J30 LSD diff (3.xx right)? Should be lower, right?

[projectRDM]

Thanks to those with NA SRs who shared their experiences.

I'm getting around 27 mpg in my stock SOHC, being easy on the throttle, but I'm still looking into the N/A SR swap as well.

I've also looked at changing the rear end.

With stock open diff (4.xx), I get 3400 rpms at between 70-75 mph.

What kind of rpms should i be at with the J30 LSD diff (3.xx right)? Should be lower, right?

Only the J30t has a different ratio, and IIRC it's 3.92:1, so it's not much of a change from 4.08:1. You could do a 3.55:1 from a Q45 but your car would be a turd in traffic.

[Syncade]

Wouldnt a DE KAT be pretty efficient? Maybe not, but id imagine so.

[KansaiDrifter]

i was gonna mention the LS1 series, but it's been gone over nicely, but the other thing that would boost the crap out of millage would be changing the rear end gears more towards a 3.0 series, the stock 4's are kinda low, plus with the torque/power curve of the ls1 you could easily daily it with something like 3.23:1 or so....

oh and the top speed is yet to be had with one of these setups! 5th gear at rev. limit was 155 mph, with a 6th gear to go, and the 4.0:1 gears, imagine what the 3.0:1 would do haha

[g6civcx]

... and doesn't cost much more than an SR swap

... it really baffles me why more people don't go LS1


I respectfully disagree.

With a complete SR front clip, and assuming the shell is manual, I can do the swap in 1 day. Figure a shop would charge you about 8-10 hours of labour.

With an LSx/T56 front clip, it would take me about 1 month to put together off-the-shelf parts and fabricate everything else. I'm not saying it's not possible. I'm saying the swap kits aren't available yet to where it's plug-and-play. A shop would probably charge you 80-100 hours.


If you add up the cost, the LSx cost much much more. I would estimate 2-3 times more than a regular SR swap, both using stock components when possible.

I've done pretty much the same swap but using an older GenI and T5 to save cost. Everything else is virtually identical to an LSx/T56 swap.


If you disagree, please say why.

[highly responsive]

LS1s actually get BETTER milage than that in an S chassis because it weighs about 800lbs less.

the people I've talked to that have one average 32-34MPG on a factory spec motor :eek3d:

and yes 340+hp

oh yeah and it weights pretty much the same as a KA...
... and doesn't cost much more than an SR swap

... it really baffles me why more people don't go LS1

It might not cost much more than SR swap, but wouldnt you still have to do a bunch of other things to do it properly? Like frame reinforcement, driveshaft, etc?

[Mr.James]

id go SR. the gas mileage is awesome, like previously stated...wonder how the CA is tho? not that i ever cared about gas mileage! and CA would be the least expensive swap as far as i know. or you could get a pack a pitbulls as your reindeer and have a s chassis as your sleigh..

[g6civcx]

Like frame reinforcement, driveshaft, etc?

You don't need any more frame reinforcement than you normally would. People with SR and KA put out insane torque figures as well.

Definitely yes on the driveshaft, but the good thing is the Driveshaft Shop will make you one for around the same price as an SR/KA driveshaft, depending on how nice you are to them. Of course there is an markup for idiotic customers.

The etc. part will be hefty. It all depends on how good you are at fabrication. Everything will need to be fabricated or at least you have to mix and match stock parts.

[Firestorm]

CA takes about as much gas as SR. believe me, i had/have both ;)

[doug810]

There is a bolt-on kit.
http://sikky.com/products/mount_kits/ls1__s14_240sx

It's on the high side but all you need is the wiring, ECU and exhaust

Other options are:
http://www.daftinnovations.com/
http://www.hinsonsupercars.com/s-3-nissan-240sx-89-94.aspx

It might cost more up front but remember you are getting 340 hp and getting 30 mpg.

[240sxaddict]

If you're worried about gas mileage you should be modifying the car to support that. Aluminum undertrays/diffuser, lighten everything, and much more.

Hell my beater hatch gets 32mpg highway if I keep it out of open loop and I'm not hauling anything.

[Dutchmalmiss]

If you're worried about gas mileage you should be modifying the car to support that. Aluminum undertrays/diffuser, lighten everything, and much more.

Hell my beater hatch gets 32mpg highway if I keep it out of open loop and I'm not hauling anything.

Honestly, lower weight and drag coefficient is where it's at. If you have balls and have AAA, then run an empty rear interior (half gutted) and no spare tire. I tried it for shits n giggles and I gained about 2-3 mpg. I just put everything back because I have passengers to take with me haha.

No matter what motor you have, the less weight to pull around = less needed power = less gas consumed = less vagina wanting you

[GSXRJJordan]

^^^ No lie.

My S14 is completely gutted. I recently added a passenger seat, and was lamenting how much weight it added (almost 30lbs with bracket/slider!).

It's literally as light as you can get an S-chassis - I guess I could run a Ti exhaust to save 10 more lbs, but shit... it's supposedly under 2500lbs (that's what another identical car weighed in at - I haven't weighed mine yet).

The motor is stock except for GT28 running on the wastegate. Probably makes 200hp.

I have C-West aero that sits less than 2" above the ground (too low, but I'm too lazy to change it right now), no wings, it's safe to say the car's aerodynamic.

I recently drove 224mi (work twice, out with friends, and then down to the beach), mostly freeway but I don't drive conservatively on the freeway - if there's an opening to spool it up for a sec, I took it...

Went to fill up and it took 8.2 gallons. >27mpg. This means I could hit 30mpg with ease. This means it makes more sense to daily drive my S14 than my Tacoma.

This is a problem for me.

[thefro526]

I DD my stock KA24DE everyday going through the same exact route to work. I've noticed that when work stresses me out in the afternoon I get substantially lower gas milage because I tend to drive a bit harder. Usually in the morning when I go to work at about 7:45 with similar traffic as when I'm going home at 3:30 I get much better mileage because I'm more relaxed. Any motor can get good mileage you just have to remeber that the street isn't a racetrack.

If you don't believe me try to do your normal drive for a week shifting at about 2700 to 3000 RPMs and you'll notice a significant change in fuel economy with only a slight decrease in acceleration. In all seriousness you almost never need to do above 3K in most drives anyways unless you need to accelerate really hard. IIRC, 3k in an SR/KA S13 is about 70 mph give or take a smidge.

I also have a friend who just bought an S13 with a turboed single cam KA and he said it get horrible gas mileage because of the tune, so a good tune changes gas mileage a lot. The same friend said when he used to have his SR he used to get great gas mileage because he never drove in boost if it wasn't necessary. IMO if I were going for fuel economy I would go SR because of the ease of the swap and when you're driving out of boost you're just driving a 2 liter four banger around.

[lazysk8er2]

if your trying to save money you would be spending more on swaps and upgrades. the effort and money put into dropping a different motor or w.e will be pointless. with that said it all depends if you just dont floor it all the time and cruise on highways with no traffic.

[Sir]

Best swap for fuel economy.

lets imagine that money isnt an issue.



wait for it...

[Vision Garage]

Get a 3 cylinder motor in there. But i swear you better not come bitching about how it has no power. You either get really good gas mileage and no power or bad mileage with good power. If you are complaining right now about gas, you are in the wrong hobby my man!

[louisdaboois]

for ultimate fuel economy swap. definately go for a D16 (or whatever) honda series motor. because they're obviously econoboxes. or drop in a 800cc bike motor.

all in all, youre 240 might not get out of its own way, but damnit, it'll get 40+mpg

[drift freaq]

I will just say this. Your car is a Sports car, Gas mileage is not a primary concern. LOL If you really are getting that concerned about Gas mileage with it then you should just buy a gas sipper. a 92 Civic will get you 35-40 mpg and cost you $1500-2k. Ya you could drop a SR,VQ,LS1, in the end you should not be putting any of these engines in for the sake of gas mileage. You will spend a lot more extra cash doing these swaps than it would cost to buy a gas saving car.
If your going to do one of these swaps it should be about the HP gains. I am doing a VQ swap, while Gas mileage gains are a plus, I have to honestly say I do not plan on daily driving the car anymore. I am putting it in for other reasons, like lots of NA HP with it being smog legal!

[redclaw05]

i just stay out of boost and my needle does not drop very much. i try to stay at less then 10% throttle as well.

[HolyShiznit]

Worried about gas mileage in the same sentence as doing a swap/power mods = fail.

Just don't mod the car. Or save up your money, buy a cheap little Honda civic to DD and THEN mod your car with whatever gas eating engine you want.

Seriously, if mileage, and premium fuel prices are something you are concerned about in your performance car then you shouldn't be toying with it.

[SoguRacing]

the best swap is no swap at all.

[hustlervibes]

What about an N/A SR? I looked around for mpg figures but couldn't find anything, short of comparing to an SR Sentra. I would assume it'd beat out a KA by quite a bit and they're not too expensive.

BTW fueleconomy.gov lists SOHC KA as 18/24 and DOHC KA as 19/26. SR Sentra is 21/29.

NA SR? What? You'd be better off with the KA. The KA has better numbers than the NA SR, why would you down grade?

[The ROMAN]

I'm saying for fuel economy. I can't find any real numbers for mpg in SR 240s aside from what people say they get, but I figure a lighter, smaller, newer motor would get better mileage than a heavier, bigger, older motor.

And yes I know the KA what still used until the latest Frontier or something, but that's a truck not a smaller car, so the aim is gonna be sacrificing mpg for extra power. Small trucks don't get the mileage small cars do.

Honestly the easiest thing is to get a civic or something, better mpg, and less worries about stuff like dings and dents.

[SoguRacing]

this thread is a waste of time. stick with what you have. it will take several years worth of gas to make up for the cost of doing the swap. You probably will never break even saving 15 cents per gallon mileage wise.

[g6civcx]

this thread is a waste of time. stick with what you have. it will take several years worth of gas to make up for the cost of doing the swap. You probably will never break even saving 15 cents per gallon mileage wise.

Sad but true. Either maintain what you have or sell completely and buy something more fuel efficient.

It's not worth the money for a swap. It will take a very long time to recoup your swap amount in gas savings.

Same analogy applies to hybrids and electric cars. The only benefit to those are less emissions.

[upstate240sx]

cadillac 500
http://www.mtscadparts.com/Engine%20pictures/Web%20eng%20pic%203.jpg

super fuel sipper

[markyboi]

best swap? swap cars with a more fuel efficient car


done.

[juls213]

This thread is retarded. The best tip I can give you is get rid of the 240 and get a scooter. They are great in gas.

[Akiros]

This thread is retarded. The best tip I can give you is get rid of the 240 and get a scooter. They are great in gas.

quoted fo mothafuckin tr00ph.

[mademedoit]

A turbocharged engine is always more efficient than na, there's a reason seim trucks are turbo. However there's a bigger range in gas mileage do to having bigger injectors. To get better mileage you should also do things like a 1 piece ds and stiffer motor mounts to reduce your drive train loss. Higher gear ratios might help you get better mileage on the freeway but you might have to give it more gas in city driving to get the same acceleration. I noticed a big jump in gas mileage with a manual sr compared to the stock auto ka24de. To answer your question though an ls1 would probably be the best swap for gas mileage.

[flip3d]

SR20DET. I drove from Orlando to Ft Lauderdale going 65 all the way. No boosting, shifting at ~2500RPM. Made it there on a little over a quarter tank. Was definitely over 30MPG.

The time before that I went all out. Boosting whenever I had a chance. Took half a tank. 20ish MPG.

[BigVinnie]

Make the right choice!!!!
VQ swap and get more torque and HP than a stock KA or SR!!!!!!
Hell you can swap a Q45 diff into the s-chassis and get even better gas mileage with a VQ than a KA and SR.... Lots of torque and displacement are your friend.....:)
VQ is newer technology, higher compression, and overall more efficient do to it's technology. It will also fit into the S-Chassis with the right mounting......

[lazysk8er2]

this thread is pointless.......best idea is to gut the car except for a cluster, shifter and a metal fold out chair welded to the bottom. slam it to the ground so its aerodynamic. get real skinny tires. weigh only 100lbs yourself. take out all the windows and put in plexiglass. get all fiberglass body parts. and drive reallly really slow. also make sure its an s13 cuz it weighs like 100lbs less. but yea def make awesome mileage there. so now you can sell all that stuff you took out and put gas in the car (mid grade). or use the money to convert to veggie oil and go to mcd's and get that shit for free.

[S14DB]

wait for it...

Yeah, isn't any swap going to cost more than the gas you save for 5-10yrs?

[upstate240sx]

doesnt the 500 in Cadillac 500 mean it gets 500 miles per gallon





or was that 500 feet per gallon?

[highly responsive]

heh, funny it was said that the best swap is no swap.
the more i have been reading, i can put down more power with my KAE than SR with the right mods. i would also like to not get fucked with when CHP pops my hood (when i go to cali)

[SHIFT_*grind*]

Yeah, isn't any swap going to cost more than the gas you save for 5-10yrs?

For real. People are so stupid about this gas mileage shit. Like the lady who spent $7,000 on a '96 Geo Metro to get an extra 10mpg over her Honda Element. Congratulations, you'll break even in about 300 years.

[eek]

If money isn't an issue why are you worried about gas and mpg? Best swap, keep it stock. Go buy a scooter and and get like 80-100 per gal. Join the next trend and sport a Honda Ruckus. :p

[zil40]

i have a ca and its not the greatest on the milleage even just cruising down the freeway thestock t25 is always in boost so its not that great for milleage but thats not why i did the swap

[CKAMC]

gearing makes a difference as mentioned earlier with the q45 diff.

followed by people learning how to drive.

SLOW DOWN

slow acceleration + low revs + overall low speed + coasting a lot + correct gearing = MPG

I averaged in my DD (06 sentra spec v) 33mpg on the highway because I took my time at 70mph instead of going 75~80

I can imagine a lightly moded VQ with the 6 speed trans and 3.7 or lower rear gear and the correct driving can pull off some amazing numbers.

[jmauld]

I think you would have the best luck if you go to a 3.5 rear end, and a small 200hp turbo setup to compensate for the gearing change. Tune it correctly and you should come out with more power and better gas mileage.

Is there a six speed transmission that will fit the KA or an alternative 5th gear for the KA trans?

[S14DB]

i have a ca and its not the greatest on the milleage even just cruising down the freeway thestock t25 is always in boost so its not that great for milleage but thats not why i did the swap

CA tranny with the KA/SR rear end? 5th gear in the CA tranny is shorter then the KA/SR. Keeps it at a higher rpm for drivability. Swap your CA bell housing on a KS/SR tranny and you'll cruse at a lower RPM.

[bboyswoosh87]

I'm newbie here whats a Ls1

[blu808]

its a 5.7 liter Pushrod v8 that can be found in 98 and up camaros, c5 corvettes, firebirds, and stuff.

350hp 350tq stock.

I have built a few. My last one a fc with a turbo ls1 made around 500 whp and got like 30 mpg.

[S14roundi]

Go with the SR DET. Factory tunes run rich to avoid detonation so just get a better tune to lean it out and you will have instant increase in MPG and more horsepower than your KA all in one reliable package.

[Colorado S14]

I get 26-28 on my turbo KA, the key is a big turbo.