No seriously, V8 Swaps

[Insanity]

You just can't ignore the practicalities of the engines. The BMW blocks can only fit up to a certain bore and stroke, and this all results in a smaller displacement than SBCs.

Yes, but it doesn't matter. If your 7L of displacement is only operating at 50% VE at a comparable RPM level, then the fact that it's 7L doesn't really matter, now does it? Displacement in and of itself means nothing. F1 is really a perfect example of it.

The DOHC LT5s with big output also had big displacement. Most likely these were the 415 ci engines, which translates to around 6.9L. That's a pretty high specific output though--around 116 hp/L. Not gonna be very streetable, eh? ;)

There are LT5s making a lot more horsepower than that. Besides, the point is that DOHC will win, HARD. You can knock off 2L and still win with DOHC over pushrods. Just look at some ferrari race engines.

Also, the BMW V8s (even the S62) have hydraulic lifters, so the valvetrain, unless it's converted to solid lifters, will suffer from valve float as well.

The pushrod engine has a lot working against it besides hydraulic lifters. For one, the one large valve has WAY more momentum than two smaller ones, so you need a much stiffer valve spring to get the same RPM without floating the valves, plus the amount of moving parts in the valve train are VERY prone to failure at higher RPM levels. Your valve floats a bit, the cam brings the pushrod up when the rocker is still a bit engaged from a floating valve and you throw a pushrod. Whee.

Tooling a small block for high revs is WAY harder than tooling a DOHC one for high revs.

[SpecM]

Tooling a small block for high revs is WAY harder than tooling a DOHC one for high revs.

-So? It still works.

-Tell me, with a strait face, that a LS6'ed e30 wouldn't be cool. I don't mean cool as in all the little Eurotrash and BimmerNatzis love it cuz it has a bimmer v8, but because it would be insanly fast, sound sexy, prob get better MPG, and not cost a whole lot more $$$ than a s50 swap. (eh, cheaper engine, but more fab work involved)

-Don't get me wrong. DOHC v8's rock. My mom has a '98 Olds Aroura with a 4.0 (244ci) four-cam Northstar and that beast will FLY. With only 4 liters, and its hauling its 4000 lb slush-box self around! But GM builds a beasty pushrod 8 too. If nothing else, a LSx weighs less than an m20 and WAY less than any contemporay DOHC v8 engines.

-Oh yeah, stop comparing race engines to street engines. Both GM AND BMW build good race AND street engines.

[ping65810]

-So? It still works.


-Oh yeah, stop comparing race engines to street engines. Both GM AND BMW build good race AND street engines.

C'mon! There is a reason we drive BMWs. I come from a GM family, and I can't help but notice that around 100k the engines become boat anchors. It might just be the 3.8, 3.1, 3.4, ALL four cylinders, oh and the 5.7 in my Blazer needed a tune up every 10k miles. I am sure they make powerful ok engines. Do they last a million miles, hell no. Practical power is a BMW trademark.

[Brew]

These are cleaner, in my opinion:

Ugly exterior, but nice swap: http://www.pbase.com/yelferrari/e30_v8

Except for the fact that the hood doesn't close. I saw the car a few years back at the Bav Auto show, and while I'm sure its very fun, IMO the car looks like shit.

[FredK]

Yes, but it doesn't matter. If your 7L of displacement is only operating at 50% VE at a comparable RPM level, then the fact that it's 7L doesn't really matter, now does it? Displacement in and of itself means nothing. F1 is really a perfect example of it.

In a world where most VEs are very similar except for maybe the very edges of the powerband, the power levels ARE NOT night and day.

If you compare the torque curves of both the LS6 and the S62, you'll see that the LS6 is down on torque at lower rpms, but overtakes the S62 at above 3500 rpm. I've attached a dyno plot of both vehicles, the data taken on the same chassis dyno at the same facility.

The S62 IS 1L smaller, but you can see that it has a slight power advantage at higher RPMs. Not the best if you plan on having a race where you keep it below 3500, but who does?

You can see by the torque curves that both engines are flow limited at upper engine speeds by the way the curves die down quickly.

The pushrod engine has a lot working against it besides hydraulic lifters. For one, the one large valve has WAY more momentum than two smaller ones, so you need a much stiffer valve spring to get the same RPM without floating the valves, plus the amount of moving parts in the valve train are VERY prone to failure at higher RPM levels. Your valve floats a bit, the cam brings the pushrod up when the rocker is still a bit engaged from a floating valve and you throw a pushrod. Whee.

Tooling a small block for high revs is WAY harder than tooling a DOHC one for high revs.

It may be harder to get an OHV engine to rev high, but considering the cost of doing anything to a BMW DOHC engine, the point is rather moot unless you have a race team with an engine development budget. ANYTHING for a BMW engine is priced in the stratosphere.

Getting an S62 to equal a LS7 in absolute output (area under either HP or torque curves) will prove to be an expensive task indeed. You're probably better off going with the V10 S85 because most of the work has already been done for you. The cost, for the time being, is obscene due to the lack of wrecked M5s and M6s.

If we are talking engine transplants, the original point of this thread, your best bet is to be reasonable and not spend $25,000 on a $3,000 car with 4x100 wheels and a rudimentary front and rear suspension. Sure, you can drop in a 4.3L Ferrari V8 into your car, but it'd be hardly worth it.

Once again, DOHC is technically superior in almost every respect in comparison to OHV. However, IN PRACTICE, if you consider BMW and GM engines as your only two options to transplant into a car, the GM engine will have more output than the BMW engine for a given cost.

A NEW LS2 costs around $6500 for a longblock. The LS6 (Cadillac) costs around $7500. A USED S62 can be had for around $10 to 11,000. New you might be able to get your dealer to order one for $17-20,000 for the longblock. The transmission is a separate thing altogether. We know which one costs more...:D

[Insanity]

First, no it will not take much effort to get a better powerband out of the S62. Hardly any at all. The s62 (and all BMW v8 ) camshafts are designed for smooth daily driving operation in a luxury car. The LS/LTx camshafts are NOT. Same thing with the manifold. Mess with the intake manifold and retard the cams on the s62 and you're going to see a drastic high-end improvement, end of story.

Also, your graph really only serves to prove me right about the s62 being set up entirely for a luxury car, and ALSO proves why it gets much worse gas milage than the LS, because while 1000-3500rpm doesn't mean shit in a race, it means EVERYTHING to someone driving around town.

[FredK]

First, no it will not take much effort to get a better powerband out of the S62. Hardly any at all. The s62 (and all BMW v8 ) camshafts are designed for smooth daily driving operation in a luxury car. The LS/LTx camshafts are NOT. Same thing with the manifold. Mess with the intake manifold and retard the cams on the s62 and you're going to see a drastic high-end improvement, end of story.

I didn't say that it would take EFFORT. I said it would take MONEY. Schrick cams are $2100 alone. Installing different intake trumpets and making intake modifications for better flow would all cost an arm and a leg. The installation itself would be fairly simple and wouldn't take much effort!

Nowack has a power increasing program just like this, where they make mods to the entire intake tract, the heads (for increased flow), and sport camshafts. They have obtained 500+ hp from the S62, and increased the redline to around 7700 rpm. They even have a stroker version that displaces 5.5L.

Also, your graph really only serves to prove me right about the s62 being set up entirely for a luxury car, and ALSO proves why it gets much worse gas milage than the LS, because while 1000-3500rpm doesn't mean shit in a race, it means EVERYTHING to someone driving around town.

I don't recall telling you that you were wrong in assuming the S62 was set up for a luxury car? The table-like flatness of the torque curve would indicate that it is made for effortless driving around town. Of course, the LS6 is set up fine for beating around town as well. It might have a slug of torque starting around 3500 rpm, but it has PLENTY down low as well.

[bimmers4life]

Personally i would choose the lsx. Why? because it it easy to work on, is cheap to buy, cheap to fix and very cheap(compared to a bmw engine) to mod.

They both are great engines though.

[Morrison]

Woo they made 500 horsepower. How? By adding another LITER OF DISPLACEMENT of course. That's all that's left for the small block: more displacement.

How about boost?