Nissan VQ35/37 versus Buick 3800, and neat VQ engine vid

[Daeron]

I have noticed a few rather potent V6 engines showing up around the block lately, and noticed many of them seem to hover around 3.7-3.8 liters. The VQ is finally landing there and seems to be just hitting its stride, after 10-12 years as one of the best rated engines almost universally. The turbo regal motor has a VERY firmly established reputation of being capable of upwards of 1000 horsepower; I wonder what the big VQs will see in time.

 

However, I am not trying to compare the two motors, or any similar displacement motor, in qualitative terms whatsoever. I care not which is better for what in any sense; I just want to analyze the differences. The purpose of this post is to see what discussion it might stimulate, and to correct and expand the information I have gotten thus far if needs be.

 

I started doing some research on the Buick motor (my term for it, I have learned there is far more subtlety to "the GM 3800" than one might think. However, the key bits I have focused my thoughts on have been bore, stroke, and rod length. Before I copare those side by side, a bit of general description of the two engines.

 

The Buick engine is an iron-block, aluminum head, OHV. I was surprised to see how many GM V6s ARE still OHV, but I have prejudices regarding OHC engines that I am only now fully appreciating the scope of. The deck is relatively short, and the angle is 90 degrees. Most other GM V6s are based on the 60 degree vee, but not the Regal motor.

 

Nissan VG37D, unsure specific engine code but judging from the intelligible characters on the japanese website from which this picture came it has VVT:

The Nissan V6 is an all-aluminum, DOHC engine with a 60 degree bank angle. Single timing chain turning balance shafts which operate the twin camshafts. This engine has a MUCH longer deck, and that is the primary difference between the two. Here is a link to a high res image of a VQ35D: http://stadium.weblogsinc.com/autoblog/hirezpics/infiniti_vq35_1280.jpg

 

Here is the Bore..... Stroke.... and Rod Length for

3800 S1....86.4mm..96.5mm.........105mm

3800 S2....same......same............120.65mm

VQ35........95.5mm..81.4mm.........140mm

VQ37........same......86mm............Unknown, likely(?) 140mm

 

 

The two are almost identical when it comes to bore and stroke.. but the rods are totally different. The Series II 3800 has a taller deck and longer rods, but that was introduced in 1995; which means all of those bad-a$$ GNXs out there are running the short rod motor. At least, they were 12+ years ago. The VQ is a much taller engine, with a much longer connecting rod. I could not find specific deck height numbers for either engine, but I had anticipated (guessed) that the rod ratio, as well as bore/stroke ratio would be similar between these two engines, despite the fact that one is a two-valve CC and the other a four-valve. How much do you think the valving of the chamber is a situation of complementing the intake stroke of such a short rod and its accompanying high angles? Wouldn't the longer rod on the Nissan lend itself to higher RPMs and smoother torque delivery to the crankshaft?

 

 

My entire analysis was kicked off because, as I said, it seemed like I had heard of several recent 3.5+ liter V6s making waves out there. If anyone has these specs for engines produced by other makers, please post them up; I am curious how the motors from different manufacturers compare, both by the numbers and in real life. Any discussion or postulation that anyone has is welcome; there is no overall POINT being sought, just a general expansion of my understanding of internal geometry.

 

Now, as a treat for you having read all that, here is a link to a video of a transparent VQ35 being spun at an auto show in NY:http://www.youtube.com/watch?v=t1V8mZ96824

[BlueZ31]

nice write up on two of my favorite v6's, the Buick motor is an excellent engine, ive owned a supercharged version (97 riviera) and i think GM made a huge mistake by not offering the l67 as an option on the f-body series, or at least with a 5-speed. just like to add two things,

 

1. its an iron head motor, not aluminum. 2. the gnx/regal was the second car (im going by a timeline i know of) to use buicks turbo 3.8, the 79-82 monte carlos had a carbureted version option, but these are rare and not as reliable as the fuel injected versions of the mid 80's.

 

If i was builing a drag/strip car, the 3800 would be my first choice due to low end pull, but if a street/track car was in the works the high-rpm hp/smoothe torque delivery you mentioned in the vq series would probably outrun the 3800...

 

and dont forget the dohc 3.6 GM has installed on the sts/cts thats offered with a 6-speed and can be optioned up to 300hp....another mill to consider in a v6 shootout, as is yamaha's SHO line of sixers....

[Daeron]

You are right, I need to investigate the SHO 6 cylinder....

 

My overall original motivation was seeing if there was a common base of comparison between the VQ (as much boost as it is seeing these days) and the buick motor.

 

How similar to the old 90* V6 is this CTS motor??

[speeder]

The Buick Stage II and the GN motor have different lineage than the 3800.

 

The GN motor came with iron heads only.

 

Additionally, the SII's specs probably can't be categorized as there were so many variations of that motor made for racing. The Stage II was built in displacements from 3.4 to 4.6 liters. Unlike the GN motors,The SIIs had all roller valvetrains and aluminum heads. They also had a much stronger block, fully counterweighted billet cranks, and super long rods. Stage IIs made about 650 hp in carbureted (NASCAR BGN) form and have achieved 1800 + turbo'ed.

 

For instance, the specs on my StageII build are:

 

101.7 mm bore, 87.63mm stroke for ~ 4.2L displacement.

165.1 mm rods. Note the rod/stroke ratio - revs, anyone?

 

My decision to go with the Stage II (I wanted a V6 for engine placement and was considering a Turbo Nissan V6) was made when I saw an unassembled VQ35 that had seen some dragstrip duty with a healthy shot of Nitrous. The internals of the VQ are about half the size of the Stage. Absolutely wimpy by comparison. BTW, the VQ's rods were all bent. The VQ's internals are also noticeably smaller than the VG series. I don't believe that VQs are capable of reliable truly big (600+whp) power. An advantage would be the VQ's light weight, as the 1st gen Buick motors are quite heavy in comparison.

 

Just some personal observations -

[Daeron]

Okay, thanks for the corrections and education.. You state that "The Buick Stage II and the GN motor have different lineage than the 3800." When I said 3800 I intended to MEAN "the grand national motor," and while I understand the differences between the actual GNX motor and the later variants.. what motor do YOU think of when I say Buick 3800? The later, Rivera motor that was mentioned above?

 

As I said, I was astounded to see how much complexity and development was involved in a simple study on "the grand national motor." The only comprehensive source I could find that was relatively simple to read (ie, not having to read the entire content of a GM forum to really grok what I am looking for.) You wouldn't happen to have a handy link to a page outlining the different incarnations, and delineating what would essentially be different motors, would you?

 

Also, VERY intersting to hear about your comparison on the VG to VQ... I *knew* there was a reason I still loved that motor an awful lot for one that I have never owned.

[BlueZ31]

the 3.8 has always been a Buick mill, it was just consolodated into GM and probably to keep customers from questioning them (like camaro/firebird owners going "whats a buick motor doing in here?) they refered to it as a GM 3800 series I/II/III...

 

NOW there is a few things i failed to mention, like the 4.3l turbocharged v6 offered in GMC's typhoon and syclone truck/suv's,...these were often hooked up to an AWD system and extremely (for the time-early 90's-) fast and quick in the turns...

 

The 3.6 has no relation to the 3.8 at all, although i belive its a decendent of the cadillac catera motor, cadillacs first rwd "sport" oriented 4-door....and if you were going to drop a turbo 3.8 into your Z, i would look at the handling and performance of the firebird formula turbo (86-87' i think) because the g-bodies, even in GNX form with macpherson struts/springs arent comparable to a 2-seater true sports car like the z series..

 

i have no experience personally with the VQ, but i know that they use different bearings in the bottom end which have been proven somewhat weaker than the vg, but thats because the vg's use a stronger tri-metal bearing that isnt manufacured anymore due to lead content or something enviromentally related..*sigh* what a crock...

 

and also, the L67 supercharged and l36 NA 3800 have been proven extremely reliable under boost or otherwise motivated, in fact a recent chevy power magazine proved that they are comparetively stronger than even the lsx series v8 motors.

[speeder]

Well, I couldn't find any good links to Buick V6 info - but my understanding is that the 3800 designation is for the FWD variants of the Buick V6, which uses a different block than the pre-88 RWD Regal/GN versions.

 

As a side note, the Chevy 4.3 Turbo as in the Sy/Ty is a different engine - I know for a fact that this motor will not bolt in a Buick V6's place. A cool thing about the Chevy 4.3 is that you can use the JTR V8 mounts to install it in a Z!

[Daeron]

Just got my connection back, so this is a quick response off the top of my head..

 

I did alot of reading on the subject on wikipedia, as well as checking a couple of links found thru google. From what I understand, there were numerous revisions to the 90* V6 that was the original GNX engine, and the more modern buick 3800 (at least, the engine in my landlord's 92 FWD regal that says 3800 on the cover) is a direct descendant of that, and while crankshafts/heads might not be swappable, and blocks from a FWD car might not go into a RWD car.. the engine is substantially the same in terms of bore spacing, crank design, etc. There ARE radical differences (later engines got higher deck height I know, and longer rods than the original-- thanks for mentioning your long rods BTW, that WAS one of my key questions about the motor) but my understanding of what I read was that a real linear "sameness" existed between the older and newer "regal engines" despite significant changes, and that this sameness set them apart from the multitude of 60* V6s out there.

 

Now, (again, according to wiki, )the 4.3, and the 3.1L engine in my buddy's 95 Lumina (also from late 3rd gen F-bodies), and numerous other V6s including a 3.8 liter, are incarnations of the gen II (or revision II, i remember the roman numeral for sure) 60* V6, which was a WHOLLY wholly different engine.

 

At least, this is how I had come away from my study.. I am not a child of the bowtie. I'm not too keen on American engines TBH; not a statement of opinion, more a statement of experience and knowledge level. I was frankly surprised to learn how many of these machines are still OHV!!

 

Would you say that I have formed a fairly accurate mental picture about these engines and how they relate, for a jap car guy who didn't know squat about em until a month ago???

[Careless]

Would you say that I have formed a fairly accurate mental picture about these engines and how they relate, for a jap car guy who didn't know squat about em until a month ago???

 

If I were thinking in terms of personal opinion in your shoes, I'd ask myself which engine I would go with as a final choice.

 

If you pick the VQ, is it because you don't know enough about the Buick V6 or is it because you know enough to sway you away from an engine directly from that lineage.

 

Sounds like you did your research, but what is throwing you in one direction as opposed to the other, and are you dead sure about what you're using as key points to contribute to either choice?

 

Maybe someone can help toss in a bit more key points.

[Daeron]

If I were thinking in terms of personal opinion in your shoes, I'd ask myself which engine I would go with as a final choice.

 

If you pick the VQ, is it because you don't know enough about the Buick V6 or is it because you know enough to sway you away from an engine directly from that lineage.

 

Sounds like you did your research, but what is throwing you in one direction as opposed to the other, and are you dead sure about what you're using as key points to contribute to either choice?

 

Maybe someone can help toss in a bit more key points.

 

I'm not researching either for a potential swap; MY motivation in all this is to further my understanding of reciprocating assemblies, and why they function the way they do to put out the power they do. I feel like I have a decent enough grasp on the theories behind building a hi-power L6 at this point, and I am beginning to explore how many of those "whys" in that process will effect other IC engines, and also seeing what cylinder geometry combinations make good power in what kind of setup.

 

I have long since embarked upon a shadetree engineering degree, with curriculum designed and administered by yours truly, to yours truly. This topic is one I have been batting about and the thread is a net of sorts, that I threw out to harvest some more input from those that know the GM engine better than I, and those that know the VQ engine better than I.

 

Something is telling me that all of those super badass GNXs have long connecting rods in them.. it seems to me that if 2:1 rod/stroke ratio can be achieved on this engine, and if people are making 1100 horses with this engine, then chances are they make those ponies on long rods and the stockers probably limit things, but even that single statement is a gross oversimplification.

 

I am honing my mind, thats all. At this point the only engines I could EVER bring myself to swap into a Z would be nissan V8 or RB, and even those would take serious convincing of myself. I loves me some L-gata

[roger280zx]

 

Now, (again, according to wiki, )the 4.3, and the 3.1L engine in my buddy's 95 Lumina (also from late 3rd gen F-bodies), and numerous other V6s including a 3.8 liter, are incarnations of the gen II (or revision II, i remember the roman numeral for sure) 60* V6, which was a WHOLLY wholly different engine.

 

No, the 4.3 is of a different family than the 60* v6, and it is a 90*. The 2.8 and 3.1 however, ARE related.

[HB280ZT]

As for the history of the GM 3800 series or the Buick 3.8 engine this is the best that I have found so far.

 

http://en.wikipedia.org/wiki/GM_3800_engine

 

If you read to the end you will see that the 3.8 ohv engine has pretty much come to and end.

 

HB280ZT

[Z-Dreamer]

Here are the current GM offerings. http://media.gm.com/us/powertrain/en/product_services/2009/09car.htm