# why qr25 and not det?



## jeffinbham (Nov 1, 2003)

this may have been asked before, actually i'm sure it has. a friend and i were having a discussion on why nissan didn't just put a sr20det in the new se-rs, and opted for the qr. is it because of CARB/emission controls, or did they just want to develop a new engine?


----------



## Zac (Mar 10, 2004)

Costs. Nissan uses 3 different engines for all of their cars. They are mass produced which cuts costs. It was an ingenious move that saved Nissan from going under.

And their all good engines on top of that. The QG is very reliable, economical and even now is being shown that is a good candidate for forced induction. The QR is a torquey motor that responds great to bolt ons and can be bought in the Spec V for a very, very decent price. The VQ is just an all around winner.


----------



## jeffinbham (Nov 1, 2003)

well, i have no first hand experience, but from what i hear the qr has tons of problems, especially 2002. we can wait for chimmike to give input, apparently he has a personal vendetta against spec v's. but to address the original issue, money, it would be way cheaper to just use an already proven engine that is more reliable and makes more power than to develop the qr. they still put the na sr20 in some b15's iirc. i know i've seen some with 2.0 badges.


----------



## Zac (Mar 10, 2004)

jeffinbham said:


> well, i have no first hand experience, but from what i hear the qr has tons of problems, especially 2002. we can wait for chimmike to give input, apparently he has a personal vendetta against spec v's. but to address the original issue, money, it would be way cheaper to just use an already proven engine that is more reliable and makes more power than to develop the qr. they still put the na sr20 in some b15's iirc. i know i've seen some with 2.0 badges.


The SE w/ the SR20DE was discontinued in 2001. And it is all about business. If it costs 10 million dollars to develep an engine that will save 100 dollars on each engine in production costs, well then the company is saving money. Yes, the QRs do have problems but at the same time, a majority of those problems are caused by carelessness, abuse or neglect. I have the engine in my car. It's a grand engine for when you need a little torque, responds well to bolt ones and came (with the entire car at that) for under 14 grand.


----------



## jeffinbham (Nov 1, 2003)

well, in the spirit of saving money, it would have been better to use a det and just not develop the qr in the first place. i'm sure it had something to do with egr and the whole emmissions bullshit, deep down.


----------



## chimmike (Oct 17, 2002)

yep, I have a major vendetta against spec V's 

my boy's auto SE-R is probably the fastest non-v8 auto car I've ever been in....easily mid 15s....prolly low 15s by now...and he's gettin cams and SAFC II soon.

The SR20 is an incredibly dirty engine, emissions wise. They were phasing it out internationally anyways for something more efficient and cheaper to produce with more accuracy.


----------



## Zac (Mar 10, 2004)

jeffinbham said:


> well, in the spirit of saving money, it would have been better to use a det and just not develop the qr in the first place. i'm sure it had something to do with egr and the whole emmissions bullshit, deep down.


Turbo cars arent cheap dude. And if you are producing a few million engine units, a few million in R and D is pocket change. Especially is that R and D yields more profits. It is all in effeciency.


----------



## jeffinbham (Nov 1, 2003)

chimmike said:


> yep, I have a major vendetta against spec V's


i have seen your posts about spec v's, maybe vendetta was the wrong word, conjures images of hatfields and mccoys. 


chimmike said:


> my boy's auto SE-R is probably the fastest non-v8 auto car I've ever been in....easily mid 15s....prolly low 15s by now...and he's gettin cams and SAFC II soon.


when you say auto se-r are you talking about a b15?


----------



## jeffinbham (Nov 1, 2003)

chimmike said:


> The SR20 is an incredibly dirty engine, emissions wise. They were phasing it out internationally anyways for something more efficient and cheaper to produce with more accuracy.


so it was a combination of emission problems, and a budget issue? was nissan really on the verge of going under?


----------



## chimmike (Oct 17, 2002)

jeffinbham said:


> when you say auto se-r are you talking about a b15?


correct.

Yes, Nissan was in a very bad way financially. Since Renault has infused the needed cash, Nissan has taken proper steps, following the Nissan 180 plan for a 3 year turnaround with big sales goals.....and they're back in a strong way.

Basically they wanted to move to cleaner, more efficient engine designs. The QR25 is an open deck block, which gives exceptional cylinder cooling, but also is weaker than a solid deck design like the QG18DE or SR20. This is why the high hp QR25s have to be sleeved as well as all new internals and massaged crank.

Another thing about the QR25 is the stock valvetrain will tear itself apart at about 6700rpm. Then between 7100-7300rpm the crank itself will fracture and go bye bye.

it's not made to be a high revving motor, much like the SR20 is known to do. If I had my way, I'd be sporting and sr20det as well as my project.

It's nice to be different, but the latest QR25 full build has had a problem each time they fixed something, and when you're talking a build that EVERYTHING is custom on...it adds up to double or more the price of the SR20DET, and you're still only able to make the same amount of power as the SR20DET without really building the sr at all....


----------



## jeffinbham (Nov 1, 2003)

chimmike said:


> It's nice to be different, but the latest QR25 full build has had a problem each time they fixed something, and when you're talking a build that EVERYTHING is custom on...it adds up to double or more the price of the SR20DET, and you're still only able to make the same amount of power as the SR20DET without really building the sr at all....


when you say full build, do you mean something someone is doing custom, or just a revamp that nissan is doing themselves?


----------



## chimmike (Oct 17, 2002)

custom job. Nissan isn't revamping the QR like that.


----------



## jeffinbham (Nov 1, 2003)

chimmike said:


> custom job. Nissan isn't revamping the QR like that.


but maybe they should, huh? but that would cost even more cash. so there isn't an sr20 being produced at all anymore, anywhere?


----------



## sethwas (Apr 30, 2002)

I think the 2 reasons are torque and emissions. (plus probably cheaper design to build)

Seth


----------



## niky (Jul 20, 2002)

The SR20M is still used in some asian models, basically, it's a SR20DE with electronic (vs. distributor based) ignition. It's muffled by a lot of cats, but it's still there, at least until the Nissan Serena van is phased out locally in favor of the Quest or a similar model.

the SR-series actually has a good amount of torque for its size.

The emissions thing was only part of the problem with the SR. I think a major factor is age. Both the SR and RB are pretty old as far as motors go, and R&D money spent rectifying emission problems and increasing efficiency on old engines is often more easily spent developing new ones that don't have the problem in the first place. In line with what NickZac said... that money they spent developing new engines would have gone down a long dark hole if they'd used it to modify the SR20 to meet emissions AND fuel efficiency targets while STILL maintaining some semblance of power. With new requirements, our old engine designs get weaker and more constricted every year.


----------



## Zac (Mar 10, 2004)

niky said:


> The SR20M is still used in some asian models, basically, it's a SR20DE with electronic (vs. distributor based) ignition. It's muffled by a lot of cats, but it's still there, at least until the Nissan Serena van is phased out locally in favor of the Quest or a similar model.
> 
> the SR-series actually has a good amount of torque for its size.
> 
> The emissions thing was only part of the problem with the SR. I think a major factor is age. Both the SR and RB are pretty old as far as motors go, and R&D money spent rectifying emission problems and increasing efficiency on old engines is often more easily spent developing new ones that don't have the problem in the first place. In line with what NickZac said... that money they spent developing new engines would have gone down a long dark hole if they'd used it to modify the SR20 to meet emissions AND fuel efficiency targets while STILL maintaining some semblance of power. With new requirements, our old engine designs get weaker and more constricted every year.


The SR is comparable to the LS1...an excellent engine but a dinosaur in technology. The VQ35DE which is replacing the RB may not have the potency but offers many advantages over the RB, especially costs. Less money spent building = cheaper MSRP.


----------



## Binger (Aug 29, 2002)

NickZac said:


> The SR is comparable to the LS1...an excellent engine but a dinosaur in technology. The VQ35DE which is replacing the RB may not have the potency but offers many advantages over the RB, especially costs. Less money spent building = cheaper MSRP.


They have been doing testing with some of the JGTC racing teams to develop a twin turbo version of the vq35 for the new gtr skyline


----------



## Zac (Mar 10, 2004)

Binger said:


> They have been doing testing with some of the JGTC racing teams to develop a twin turbo version of the vq35 for the new gtr skyline


Should be exciting. The NA VQ is a very good engine, and a TT version should yield impressive results.


----------



## jeffinbham (Nov 1, 2003)

NickZac said:


> Should be exciting. The NA VQ is a very good engine, and a TT version should yield impressive results.


if you look at some of the turbo kits available for the vq, they don't seem to add that much power, or atleast, not as much as they should, imo. (for the price and everything). i think the vq has been tuned almost to it's max from the factory, and that's why it's so damned good already. case in point, look at the hyped up s tune and r tune packages for the 350. seems like a waste of cash to me.


----------



## chimmike (Oct 17, 2002)

Jeff, keep in mind the turbo kits aren't made for absolute power, and the internals of the VQ can't stand up to the rigors of high power boost. Also keep in mind that the VQ is an open deck design...which is why AEBS made a sleeves for it recently (as seen in NPM) 

it's still a great engine, and wiht stock boost (7psi) on the stock engine is a formidable machine. The Greddy kit is also CARB and 50 state legal 

however, I'm really liking the looks of this HKS Rotrex supercharger...a centrifugal unit featuring planetary gears (i can't explain that, I am not an engineer....i'm still learning all this stuff) and it's supposed to be an amazing unit.


----------



## Zac (Mar 10, 2004)

chimmike said:


> Jeff, keep in mind the turbo kits aren't made for absolute power, and the internals of the VQ can't stand up to the rigors of high power boost. Also keep in mind that the VQ is an open deck design...which is why AEBS made a sleeves for it recently (as seen in NPM)
> 
> it's still a great engine, and wiht stock boost (7psi) on the stock engine is a formidable machine. The Greddy kit is also CARB and 50 state legal
> 
> however, I'm really liking the looks of this HKS Rotrex supercharger...a centrifugal unit featuring planetary gears (i can't explain that, I am not an engineer....i'm still learning all this stuff) and it's supposed to be an amazing unit.


I've heard only a little of the Rotrex but not too much about it. If it is HKS, I can only imagine it will push the boundary further than it was previously believed.


----------



## jeffinbham (Nov 1, 2003)

chimmike said:


> Jeff, keep in mind the turbo kits aren't made for absolute power, and the internals of the VQ can't stand up to the rigors of high power boost. Also keep in mind that the VQ is an open deck design...which is why AEBS made a sleeves for it recently (as seen in NPM)
> 
> it's still a great engine, and wiht stock boost (7psi) on the stock engine is a formidable machine. The Greddy kit is also CARB and 50 state legal
> 
> however, I'm really liking the looks of this HKS Rotrex supercharger...a centrifugal unit featuring planetary gears (i can't explain that, I am not an engineer....i'm still learning all this stuff) and it's supposed to be an amazing unit.


but right now, the internals are probably already stressed, considering the amount of power being made combined with the relatively high rpm that it's known for. correct? my roomate drove one (he has an n/a z31) and said that the way the engine ran and the gears reminded him alot of his car, only better. he claims he barked shifting into 4th. i don't know if it's true, but if so, god damn!! anyway, how would a centrifugal supercharger (like a vortec right?) be better than a turbo? cause i was looking at the vortec on my old roomates boyfriends gt mustang, and it appears to be a belt driven turbo, not one of those old top mount screw induction superchargers, i think they are called roots type.


----------



## Marvin (Oct 16, 2002)

jeffinbham said:


> well, i have no first hand experience, but from what i hear the qr has tons of problems, especially 2002. we can wait for chimmike to give input, apparently he has a personal vendetta against spec v's. but to address the original issue, money, it would be way cheaper to just use an already proven engine that is more reliable and makes more power than to develop the qr. they still put the na sr20 in some b15's iirc. i know i've seen some with 2.0 badges.



This may have already been said, but Nissan puts the QR25 in a car with the intent of it not being manipulated. I really don't think any engineer was sitting in his office and said "Boy, i bet aftermarket tuners would sure love an SR in here more than a QR."

All cars leave the line as if they are to be left bone stock.


----------

