RB20DET fuel mileage

[carbully]

Hi, Newbie here! I really did search this with no results. I plan to get an S14 for a future engine swap but don't have the car yet. I am married with kids so am not looking for big power or an expensive project, just want a fun car with good fuel mileage.

I was just researching the SR20 and the RB20 options for the swap (becuaase I will sit here and obsess about this until I have the $$ to do it) and can't find anything on what kind of fuel mileage I can expect from a stock RB20. I have talked to a couple of SR guys who claim to get 28-30mpg out of their stock setups.

So, what kind of fuel mileage are you guys getting out of your stock RB's? My curent car is a 1st gen Integra that gets 32mpg but I am hoiping I can end up with a much more fun car that gets close to the same mileage!

[JerryRigRB240]

Wow, "not looking for big power or an expensive project, just want a fun car with good fuel mileage."

You should keep the stock KA. There is absolutely no reason to swap an RB in if you don't want an expensive project. RB20 can be done relitively cheaply, but fixing and finding parts is quite a hassle. Also 240's are plenty fun with the KA. BTW you should get around 30 highway with a stock RB20.

[Bronze MFP]

rb20's can be cost effective as far as swaps go. Just make sure you get an engine from a reliable importer (jhot and jarco are highly reccomended) mkae sure you replace all the maintenece bits (water pump, timing belt, timing belt pullies, thermostat, etc) and you will have a reliable swap. my "stock" swap has given me no troubles what so ever in over a year. Gas mileage with the stock swap should run about 26-30mpg average depending on how well your fuel system is, how much highway driving you do, and of course how heavy your right foot is.

p.s. expect to spend 3-5,000 to do a rb20 swap right.

[Carl H]

and when he says reliable he means reliable to the point it was driven nearlt 25k mi in one year...

[Sil240]

For the amount of power your going to get out of a stock RB20 and for the $$ you should just do a KA-T.You'll get more HP & TQ for less $$.Plus replacement parts are easy to find.

Lets say you find a RB20 for- $1200Mounts- $250Downpipe/Turbo outlet- $250IC & Piping (Ebay)- $250E-Fans &Tstat- $175Wiring- $250Assuming your doing the rest of the work yourself. And not doing any of the regular reccomended maintainence. And your motor comes in good condition.I'm probably forgetting other things too.(Not including exhaust etc...)

How much does a KA-T kit cost?The motor will be in the car already too.My friend hit 300whp stock motor with a Early Boost designs kit.

Now for Gas mileage, I have NO idea.I guess if your cruising just stay outta boost.

[Darius]

I'm with Sil240 on this one. For the money you will spend on getting the RB20 swap done with stock hp, you could have built a pretty sweet setup on your current KA and had way more power. Plus the parts you use will be easily sourced at a local NAPA.

[carbully]

Thought about the KA-T, but the fuel mileage is only ~26mpg on the highway in N.A. form, it's going to go down with a turbo I would think. And, from what I have seen, a good turbo kit would still cost me about $3k, so don't think I would save any money.

It's true, though, that the availability of RB parts kind of scares me. That and I am concerned that if I do have to work on it it might be so tight that I might have to pull the motor to do maintenance down the road like timing belt/water pump?

The reason I want to go RB instead of SR is the sound of the motor, and I think SR's are too common. I want about 200-220hp and the option that if I want to go up from there someday I will have a good base to start with.

[Sil240]

Your gonna end up spending WAY more than 3k on a RB20 swap.

You can't jump into a RB swap with Gas Mileage and a small budget in mind.That's what I thought, but then I ended up spending ALOT more than 3K.

If you get a Rom tune or whatever those KA guys are tuning with, but if you can get a Rom emulator or something capable of holding more than 1 map/program. Then you can run a performance tune and a Gas mileage tune.

Oh and you better do a clutch while the motor is out. If not your gonna have to pull the whole motor out again.Trust me.I know.

[Bronze MFP]

whats wrong with stock(ish) HP? i've been rolling around like that for a year and am still having fun with it.

as for cost, quit throwing the freakin mout kits in on an rb20 swap... its expensive and unnessisary. Here is what my swap ran, roughly:

engine set from jhot: $1,650 shippedr32 crossmember from jhot: $80 shippedjun lightweight flywheel: about $300 shipped (cant find prices on nengun anymore, discontinued)RPS sport clutch z32 $284Tomei fuel pump: $287nismo engine mounts: $71.23 shppied each (x2)Nismo trans mount: $75.37 shippedGreddy timing belt: about $100 shippedtiming belt idler and tensioner pulley: $160

apexi air filter: $91.16

water pump about $100 shipped

thermostat about $65(cant quite remember on that one but whatev)

greddy profec-b boost controller $150

gauges (boost, water temp, afr) $300

misc hoses, radiator hoses and heater hose adapters: around $100.00

factor in about another $100 for trans oil, coolant and engine oil

thats a grand total of $3919.99 of stuff I can remember. some of those parts were unnessisary, like the air filter or the light flywheel and boost controller, but you get the point. Swap was done december of 2005, and since then I have put on 36,000 miles. not once has the engine died on me, not started for me, or been a blast to drive. Will i upgrade power in the future? sure, but the stock swap is nothing to scoff at. its fun, reliable and not too horrible on gas. now for going KA-T? better buy a good kit... ask carl h how his install on a friend's car is goin lolz!

[Sil240]

I'm not saying there's anything wrong with the stock RB power. But just going by #'s the 20 usually puts like 185hp to the ground

A good running KA-T would put down like 275 more or less.Yes, I know because its a bigger turbo.But it's HP per $.Plus adding some type of Muli-map/program ecu. So you can have some power when you want and then cruise and be green going to work.

I love my 20, now that she's working. lol

[Spazz]

+1 for a rb20 swap..... inline 6's sound so damn sexy

[Carl H]

good luck finding decent management for the ka-t.if i were to do one i would be running that **** off of a power fc...

[NISMO_RB25]

I know this is the RB forum, but I got say that I would just go SR20 for your needs. Easy swap, no customs mounts, driveshaft etc..Parts everywhereCheap

Some of my friends have SR20's and stock SR's are a lot of fun and still get good mileage.

I love my RB, but if I was in your situation I would just do the SR swap.

[carbully]

Yep, honestly I am still considering the SR, but I did not just say that on the RB forum!!! That's why I want to hear from some people about what fuel mileage you guys are getting and other potential problems, etc.

This is what I have so far:

RB20DET=awesome sound. cheapest swap motor. Reliable. hard to find parts for. harder to work on without removing engine? 26-30mpg.

SR20DET=relaible. Slightly more expensive than RB20 initially, but replacement parts are cheap. Not too hard to work on. Does not sound like an RB. 28-32mpg.

KA24DET=Very cheap motor, but kits seem like they are around $3200 anyhow. Fuel mileage probably in the low 20's hard to say 'cause they are all over the place in AFR, hard to find one really tuned well. Unknown fuel management system, have to experiment and probably have to constantly mess with stuff 'cause I am a perfectionist and don't want to deal with flat spots/lean spots/rich spots/mapping from scratch. I have kids and want to spend time with them, not so much with my car, so want as much of a turnkey setup as I can get, so I am sticking with stock. Hopefully Nissan already handled the tuning on the RB and SR motors so I will be happy with how it runs. I don't even want to go there.

So, I'm leaning heavily toward the RB20DET based on similar mileage and great sound, but need to hear from more of you about your mileage!
Modified by carbully at 4:55 PM 2/9/2007

[BoostFab]

the ka-t w/ bad mileage is because it's not properly tuned.

[Bwana]

Consider the CA. As cheap/cheaper than the rb20, easy swap, excellent fuel mileage (Ryan gets 32 mpg on the hwy with his, 250whp running SDS standalone) and a better engine than the SR (imo). Just something else to consider...

[Carl H]

while the ca is indeed a stout motor most of them need to be rebuilt because they are just so old...

[carbully]

Found a guy here at work that has an S13 with RB20DET done completely stock like I was thinking of, and it's a real nice package. He drives a lot of stop-and-go here in Seattle so averages 20-26 mpg, but on the highway gets ~30mpg. I would do mostly highway driving.

Ran extremely smooth, no hesitation or lean spots, and PLENTY fast with stock boost. I know my S14 will be a little heavier, but I think I am sold on the RB20 now!!

[Spazz]

welcome to the family!

[bardabe]

welcome to the family!

what he said. =] welcome to the FAMILY!

[bigk]

good luck finding decent management for the ka-t.if i were to do one i would be running that **** off of a power fc...

Maybe acouple of years ago but not now.jwt rom tune, ethalpy tune, bikirom, megasquirt, aem ems, haltec etc....

http://www.ka-t.org/forums/vie...de1ac

[Carl H]

thanks for telling me what i already know.im tuning a biki equiped car right now and it blows.ms has low resolution for maps and the ems as well as haltech are out of most peoples budgets.jwt is stupid due to the uber rich and retard modes they run and enthlapy requires the use of a s13 ecu...as i said still not alot of decent management out there.

[Yellow4g63]

I didn't know you had to pull the motor to maintenance work when you have a RB20. I always thought you just pull all the crap out of the front end to fit the air gun in there.

[Sil240]

I didn't know you had to pull the motor to maintenance work when you have a RB20. I always thought you just pull all the crap out of the front end to fit the air gun in there.

Who or what are you reffering too???I'm lost, don't know what you were responding too.

[Monkey87]

Your gonna end up spending WAY more than 3k on a RB20 swap.

Oh and you better do a clutch while the motor is out. If not your gonna have to pull the whole motor out again.Trust me.I know.

That's what he was referring to.