OPINIONS WANTED: SR20DET vs RB25DET

[HELLRAZOR]

I'm looking at buying two different cars, both similiar body styles and similar mods.

Price isn't the issue, really. I just don't know enough about these two motors to make a well informed decision.

Lets say they both have the same bolt ons, similiar builds, same size turbos, injectors, etc.

Which one is better? Which one will do more down the road? Which one is more reliable?

Assuming they are both putting out about the same HP, they both claim to be in the mid 500's, what are the pros and cons on each and why?

Thanks in advance.

[HELLRAZOR]

no opinions??? very strange

[roscoe]

RBs get you laid..... but seriously, may want to consider the price/availability of parts for each also.

[Arm&hammer]

rb's harder to find and more expensive. they are both good boosted motors excpet the rb awd & is in a skyline and the sr20 is from a silvia. if money wasn't an issue id get the rb. what is it going in?

[4eyedbox]

I'm looking at buying two different cars, both similiar body styles and similar mods.

Price isn't the issue, really. I just don't know enough about these two motors to make a well informed decision.

Lets say they both have the same bolt ons, similiar builds, same size turbos, injectors, etc.

Which one is better? Which one will do more down the road? Which one is more reliable?

Assuming they are both putting out about the same HP, they both claim to be in the mid 500's, what are the pros and cons on each and why?

Thanks in advance.

To begin with, both engines will require new turbo, turbo manifold, injectors, and fuel pump. Given that:

It's my opinion that a SR with 500hp is merely a ticking time bomb. I know that some SR fanboy will jump on here and tell me I'm full of chit, but whatever... it's a time bomb. SR's are known to be notorious for spinning bearings and having a weak valve train. In order to make a SR a viable option at this power level, one must spend some serious attention on beefing the weak valve train up. I actually have a friend that is in the process of building a 500hp SR at this very moment, and in the name of reliability he is having to drop some coin to get it there. He's needed to purchase upgraded valves and springs, new performance valve guides, solid rocker pivots, rocker arm stoppers, and upgraded rocker arms all in the name or reliability. In the quest for 500hp, he also needed to add a set of cams as the stockers just want do the job. The factory rods and pistons aren't very valid for making this kind of power either, so new rods and pistons are needed as well. After all of this is completed, you MAY have a reliable 500 hp car. I know that my friend that is building his plans on 500 being his high boost/race fuel setting, and driving the car daily detuned to around 350-400 in order to promote longevity of his engine.

And then there is the RB25, which would be my choice for 500hp between these two engines. The RB25 is a much more robust engine. Completely stock internal RB25's are known to be putting down 500+ with nothing more than a new manifold, turbo, fueling, and a good tune. They are also running these power levels on a daily basis. It's not until after the 500 and change mark that anything internally needs to be addressed.

Now as for your question about which will do more down the road... The RB25 will. The SR is reaching is limits at 500 for an everyday street car, where as the RB25 is still on stock internals. Change the cams, valve train, port and polish, and add a new set of rods and pistons and the RB is good for quite a bit more power.

Ultimately the choice is yours to make, but I would much rather have the RB25 with it's 2 extra cylinders and ample room for growth over a SR.

[TougeGTR-33]

^ Nice Write up!

[Sinfix_15]

To begin with, both engines will require new turbo, turbo manifold, injectors, and fuel pump. Given that:

It's my opinion that a SR with 500hp is merely a ticking time bomb. I know that some SR fanboy will jump on here and tell me I'm full of chit, but whatever... it's a time bomb. SR's are known to be notorious for spinning bearings and having a weak valve train. In order to make a SR a viable option at this power level, one must spend some serious attention on beefing the weak valve train up. I actually have a friend that is in the process of building a 500hp SR at this very moment, and in the name of reliability he is having to drop some coin to get it there. He's needed to purchase upgraded valves and springs, new performance valve guides, solid rocker pivots, rocker arm stoppers, and upgraded rocker arms all in the name or reliability. In the quest for 500hp, he also needed to add a set of cams as the stockers just want do the job. The factory rods and pistons aren't very valid for making this kind of power either, so new rods and pistons are needed as well. After all of this is completed, you MAY have a reliable 500 hp car. I know that my friend that is building his plans on 500 being his high boost/race fuel setting, and driving the car daily detuned to around 350-400 in order to promote longevity of his engine.

And then there is the RB25, which would be my choice for 500hp between these two engines. The RB25 is a much more robust engine. Completely stock internal RB25's are known to be putting down 500+ with nothing more than a new manifold, turbo, fueling, and a good tune. They are also running these power levels on a daily basis. It's not until after the 500 and change mark that anything internally needs to be addressed.

Now as for your question about which will do more down the road... The RB25 will. The SR is reaching is limits at 500 for an everyday street car, where as the RB25 is still on stock internals. Change the cams, valve train, port and polish, and add a new set of rods and pistons and the RB is good for quite a bit more power.

Ultimately the choice is yours to make, but I would much rather have the RB25 with it's 2 extra cylinders and ample room for growth over a SR.

Basically what this long winded cat just said was "if you want to just bolt a turbo up to something, RB is better"

SR20 is more than capable of reaching reliable 500hp. The reliability opinions of the poster above are pulled out of his ass.

[hondalover00]

yeah sr have known issues to having spun bearings...but if money isn't the issue...building the sr will be great in my opinion....they are all over....while rb's seem to be harder to find

[Sinfix_15]

yeah sr have known issues to having spun bearings...but if money isn't the issue...building the sr will be great in my opinion....they are all over....while rb's seem to be harder to find

couldnt have anything to do with people dropping fresh ebay sr20s with "40k miles" right into their cars could it???????

[4eyedbox]

Basically what this long winded cat just said was "if you want to just bolt a turbo up to something, RB is better"

SR20 is more than capable of reaching reliable 500hp. The reliability opinions of the poster above are pulled out of his ass.

Hate to say I told you so, but...

I know that some SR fanboy will jump on here and tell me I'm full of chit, but whatever...

couldnt have anything to do with people dropping fresh ebay sr20s with "40k miles" right into their cars could it???????

It could; however, even built engines are known to have this problem. IIRC it has to do with a sub par oil delivery system. I don't recall if it is the oil pump, oil pickup, or both that cause the oil starvation on SR's; regardless the issue is there along with the others that I mentioned above.

[Sinfix_15]

Hate to say I told you so, but...




It could; however, even built engines are known to have this problem. IIRC it has to do with a sub par oil delivery system. I don't recall if it is the oil pump, oil pickup, or both that cause the oil starvation on SR's; regardless the issue is there along with the others that I mentioned above.

oh wait, let me post my disclaimer before i type out some random nonsense.

"I know some RB fanboy elitest is gonna pretend to know it all in this thread, but here goes..."

there... now that ive said that.

Your minor concerns with an engine show how amateur you are. youre writing off an engine because you think it has a bad oil pick up????

that would be like me saying.... " hey, those LS1s are shit, that plastic cover they put over the valve cover is known to crack"

like i said in the post above. Your opinions of both engines are what you're regurgitating from the 2 fast 2 furious handbook and the general logic of an amateur car builder. None of the problems you mention mean shit to anyone who is building an engine. If you just want to drop something in your car and bolt a turbo to it... yeah... RB is better. If youre building an engine and understand what building an engine entitles, then a sr20 is MORE than capable of meeting the 500hp goal and doing it with reliability. above you're like OMFG my friend had to change cams.... as if thats some major surgical procedure in the car world..... i was changing cams when i was 16 years old. If you're a ebay parts monkey that cant do anything that isnt a bolt on, then yeah, buy an RB because you'll probably never make enough HP to tear a stock one up. If you want to build a small economical engine that is readily available and capable of meeting your street car HP goals, SR20 more than fits the bill.

Where did i form this opinion???? under my own hood... My engine is 3 years old. It's been on many a race track. I can hop in it, drive your granny to her Dr's appointment, pick up some groceries for your mom, take your sister to the airport then drive cross county to watch the lakers game, stopping at every drag strip along the way.

[hondalover00]

i have to say well said sinfix

[seanrg1116]

rb25>SR

2jz>rb25

2jz=RB26

[redrumracer]

for reliability id go with the rb. its proven to make that power easily, no replacement for displacement, and power spread over 6 cylinders less than the same power spread over 4 cylinders.

[boosted347]

i would go rb if it was me both are good motors, not knocking either...but when you say further down the road in "most" cases the rb will be able to put out more power

[RUFFIAN]

if $$$ is no object, get an RB26DETT.

[crazystang25]

if $$$ is no object, get an RB26DETT.

+1

[Cameron.]

rb25, but im biased. i daily mine over 400hp.

[906bolt]

I think that he said both were built in some way, so there is a chance that above issues/ real or imagined would have been addressed. That said a well built motor is going to hold up to the point the weakest link fails at, regardless.
1.) The SR is going to be lighter, but probably not make the torque
2.) The RB is heavier, but will not have to work as "hard" to make the power.
3.) I would prefer the RB, just for the fact that bolt ons are going to have more impact on the power overall, again generally
4.) I dont see a sr and rb having similar power with the same turbo's and such, but i have been known to be wrong

[msanch24]

rb25, but im biased. i daily mine over 400hp.

not biased. good, first hand experience that will definitely help him make his decision!