4.6 options

[lanceslambos]

it has occurred to me that i could have just got a used 4.6 for the money i've thrown at the 4.0 in the last 60 days. so if i were to get me a 4.6, which models and years would i want to look at? specific models and years? there are so many variations of the 4.6 with different hp and torque ratings, etc. i don't know where to begin but i would want one that mounts right up to the existing tranny, motor mounts, radiator, etc.

[aurorabrain]

96-99 are all good for a swap. There is a VIN "Y" and "9" or 275hp and 300hp versions. The only difference is the intake camshaft.

[Marc]

My choice.....the 300 HP.

[lanceslambos]

yes. i mean which Cadillac models would i look into to. STS, DTS, escalade, etc. if i knew the models that had a 4.6 that could bolt right up, i would then determine out of those which one has the best power curve

[XJSman89]

If its all the same engine then it wouldn't matter which one you pulled it from. The power curves are different because of other factors. Say the power curve shows that the STS is faster. I assume the engine is the same. Thus it doesn't matter that the power curve is higher... an engine from a DTS into an Aurora will give the exact same performance as an engine from an STS into an Aurora.

[lanceslambos]

hhmmm, you seem pretty confident about that.

[robaurora01]

its the tranny that decised most of it

[aurora4]

doesnt one of them have better top end and the other low end?

[oldwino]

275 hp has better bottom end torque.

[KliffsAurora]

Torque is your friend, go for the 275hp VIN Y engine. Either or you will be happy I'm sure.

[aurora9740]

my first choice is the the 275hp. with the higher torque you get the low end power and the hp can be bumped with minor modifications such as intake and exhaust etc etc. IMO

[XJSman89]

Oct 31, 2009 15:26:13 GMT -6 lanceslambos said:

hhmmm, you seem pretty confident about that.

That's because I'm pretty sure I'm correct. ;D

Like Rob said, most of it is decided by the tranny. If the engine is the same then it won't magically put out more power in one car or the other, its power is utilized differently by factors such as what tranny it has, etc.

[RCA1186]

Exactly, tranny, weight, tires, exhaust system etc.

[RCSRGREAT]

ive driven a 4.6 northstar and id honestly say id rather have my 4.0.... now i dont know how a 4.6 would be like in my aurora but the 4.6 in a STS i drove i didnt like... it felt slow to me, low end wise...

[95mushroom]

LOL, the blind leading the blind on this one...


As aurorabrain pointed out, you have two engine to pick from. I'm not sure where the concept there were multiple types of Northstars running around come from (maybe the first Northstars, which made a few hp less? , however they aren't applicable for a swap into an Aurora). And the only difference between the two, is the intake camshaft. The Escalade never used a Northstar, neither the CTS, and the SRX wasn't around. You can either pick from Seville STS/SLS or 96-99 Deville/Deville Concours (Concours has the Vin 9 300hp motor). I personally would look at just in-between a 98-99 Seville SLS/STS. The term "DTS" didn't arrive until the 2000 model year, when the Deville moved to the G-body platform, and then you saw the trim levels change to DHS/DTS.

The difference in the two motors, is the the Vin Y 275hp makes a lot of power/torque down low. The Vin 9 300hp motor makes almost all of it's power up top, actually nearly at redline. Though, it's not like Vin9's don't have power down low either, just not as much. Compared to the Aurora, there's still a sufficient amount more, and there are very few cars which love to scream to redline more then my STS (consult my accel vid in Non-Auroras ).

I also have no idea where you guys got that the tranny controls power. All the tranny does is receive input power from the engine, shift gears, and spin the wheels. The ECU/computer is what controls engine output.

Perhaps any personal experience with the two different Northstar power levels, is that all 275hp Northstar Cadlliacs had a 3.11 final gear, and all 300hp versions had the 3.71 final gear (same as in Autobahn's, 2nd Gen 4.0s). Whether it was due to transmission longevity concerns with the torquey motor and the 3.71, horrid traction problems down low without having to reign-in the fun, or Cadillac not wanting the base model to outperform STS. Perhaps all three, more so the latter. The only GM ever offered with the 275hp version and the 3.71 final, was the Bonneville GXP. So you'd think the GXP would be a tire-shredder of a good time, but GM put probably the strictest torque-management software ever, onto the GXP. The computer goes a long way in killing the fun.

[XJSman89]

Nov 1, 2009 21:51:37 GMT -6 95mushroom said:

LOL, the blind leading the blind on this one...

I was basing my statements of Lance's info, you can't knock me for anything because of that. ;D

I'm simply saying that power curves don't matter if the engines are the same and all you're pulling out is the engine. I'm 100% Positive that I am correct there. Now if the engines are different that is an entirely different story.

[aurora9740]

I also have no idea where you guys got that the tranny controls power. All the tranny does is receive input power from the engine, shift gears, and spin the wheels. The ECU/computer is what controls engine output.

That is such a true statement but yet retarded also in the way you make it sound. The way i read that is the you are saying you can put any tranny (given it's adaptable) behind any motor and still get performance. It doesn't really work like that. You can have one heck of a motor but if you have a crap tranny with the wrong gears in it your motor don't mean crap. The power from the engine needs to get to the axles then to the tires to make you go, and there is only one way to get it there. But all other statements made are golden. The GXP Bonneville would be a heck of a good time if the computer wasn't such junk. I have driven a couple and i laughed at each one compared to my aurora every time. You do know your stuff mushroom. Cudos on that info you threw up on specific models and such.

[KliffsAurora]

If any 4.6L bolts in then pick what you want more. Higher RPM power or lower RPM torque. I want torque so VIN Y engine is my preferred choice. ;D

[aurora9740]

yeah...you really only have two choices. top end or low end. just all depends on personal preference. personally i like the vin y for the torque down low. Top end can always be adjusted easier.

[95mushroom]

Nov 7, 2009 1:12:26 GMT -6 aurora9740 said:

That is such a true statement but yet retarded also in the way you make it sound. The way i read that is the you are saying you can put any tranny (given it's adaptable) behind any motor and still get performance. It doesn't really work like that. You can have one heck of a motor but if you have a crap tranny with the wrong gears in it your motor don't mean crap. The power from the engine needs to get to the axles then to the tires to make you go, and there is only one way to get it there.

I do see where you're going. Yea definitely, a good tranny can make the difference. This was a bit of assumption on my part, dealing with Auroras/Sevilles where there's only ever one tranny, and yea, it two gears. I bet a L37 or L47 would not be very fun with the 3.11 in there....

That said, the concept "the transmission controls power" is what I was after. I just can't thing of one situation that holds true. Even when you loose traction, the computer applies the brakes, then if necessary cuts power, at the engine, It's not like the torque converter slips an extra amount or something, or even upshifts to reduce power. I should have said something more like "all the tranny ever does is route the power from the engine to the axles, through the properly ratio'ed gears, that are selected by the computer."

[aurora9740]

Posted by 95mushroom on Nov 8, 2009, 4:31am

Nov 7, 2009, 2:12am, aurora9740 wrote:

That is such a true statement but yet retarded also in the way you make it sound. The way i read that is the you are saying you can put any tranny (given it's adaptable) behind any motor and still get performance. It doesn't really work like that. You can have one heck of a motor but if you have a crap tranny with the wrong gears in it your motor don't mean crap. The power from the engine needs to get to the axles then to the tires to make you go, and there is only one way to get it there.


I do see where you're going. Yea definitely, a good tranny can make the difference. This was a bit of assumption on my part, dealing with Auroras/Sevilles where there's only ever one tranny, and yea, it two gears. I bet a L37 or L47 would not be very fun with the 3.11 in there....

That said, the concept "the transmission controls power" is what I was after. I just can't thing of one situation that holds true. Even when you loose traction, the computer applies the brakes, then if necessary cuts power, at the engine, It's not like the torque converter slips an extra amount or something, or even upshifts to reduce power. I should have said something more like "all the tranny ever does is route the power from the engine to the axles, through the properly ratio'ed gears, that are selected by the computer."

very technically correct statement. Yeah i see your point though in the aurora with only one option for a tranny. i'm just gonna leave all my assumptions out of my mind on this one though. I do have my thoughts of how the L37 and L47 would be but would like to find out first hand.

I am currently looking for a motor for my 97 but am having no luck. Mainly because i am too cheap. All motors i have found have at the least 80,000 and people want $1600-$2500 for it. I'm not payin that when i could get a crate motor for $3300. i think i will just save up for a new crate motor. better than takin a chance on a used one with no guarantee.

[XJSman89]

I believe this is one of the best explanations of where to get a 4.6 that I've seen. Thanks, Shroom.

Another question... what are the benefits of getting a VIN Y over a VIN 9 with respect to the gear ratios? Since my autobahn has the 3.71 final would it be better to go with the 300hp VIN 9 since they're the same?

I'm just not positive on the specifics, that's all. If the final gear ratio won't matter by what engine I put on it then I guess its purely up to choice. I just wasn't sure if you could stick a 275hp VIN Y in an autobahn because of the final gear ratio. Could someone please advise?

On the slim chance that I ever got around to this I would probably go with the VIN 9 anyway just because it'll keep the autobahn name even if there is less torque.

[Marc]

You could use either Northstar with the 3.71. The 300 HP had the 3.71 from the factory. And the Pontiac Bonneville GXP had the 3.71 with the 275 HP 4.6.

[tka420]

Thank you for posting this thread.

I have been thinking about what to do to my engine lately, I need to replace my rear motor mount. Thinking about the go big or go home route.

Would be an excellent winter project for this year.

[starfire]

the other thing to remember is a Classic Aurora will need a Northstar from the 96-99 year range as changes were made to the crankshaft sensor on the 2000+ Northstars.

here is some good information on what is different year to year in the N*

www.cadillacforums.com/forums/northstar-performance-technical-discussion/199946-northstar-swaps-what-years-interchangeable-differences.html

[plato442]

Jul 13, 2010 10:18:04 GMT -6 Marc said:

You could use either Northstar with the 3.71. The 300 HP had the 3.71 from the factory. And the Pontiac Bonneville GXP had the 3.71 with the 275 HP 4.6.

Well, you wouldn't use a pontiac GXP 4.6 because they came in 2004-2005 which engines starting in 2004 should have VVT So if you're looking to transplant, keep within the same years of your Aurora. My 2001 would need a 2001-2003 engine either VIN Y or 9. The 2000 4.6 is roughly a leftover 1999 4.6. With some gasket match porting on the exhaust ports on the heads and a free'er flowing exhaust such as the Corsa or a decent shop or home made one, and some air intake work one should gain a few free HP & torque.

[NinEFivEFourOH]

Only the rwd cars had vvt, and according to most those engines wouldnt fit in a fwd car because of the size, not to mention the lack of computer support you would have... Although I would love to see someone pull it off because the vvt engines just sound AMAZING!

Lance what year is your aurora? I'd go with the same model year for simplicity. Vin y or vin 9 is up to you, I'd prefer as many ponies as I can get so my choice would be the 9... (it has the same amount of torque as the y people...). Even though I'm using a y, I swapped my cams out for chrfab 272s.

As forthe trans your computer would have to be tuned or worked on to know which trans is in the car.... It's the same deal as trying to throw an autobahn computer into a non autobahn car... It's not going to work because the jobs have 3.41 fdr where the autobahns have 3.73 or whatever it is.

Dont forget lance there are plenty of things you can do to that 4.6 before you put it in. I've been saying this for a while but when I do get around to it there will have been a set of headers and a revised crossover pipe made for an aurora that greatly increases power...