3400 250HP Naturally Aspirated?

[enderw88]

I am researching engines for an upcoming project car. In this case a Stalker (if I can figure out the engine). I am not familiar with US engines and my most recent experience is with my 2.8L BMW motor (187HP 200 ft-lbs, 66BHP/L). I am curious what it would take to get a 3400 to put out 200-250 ft-lbs of torque and 200-250 HP, naturally aspirated. I realize that is a pretty broad range, but I am sort of surprised that these engines seem to have such low specific output. My research, which could be wrong, seems to indicate that an N/A 3400 would typically be make 170 ft-lbs of torque and 160 HP (47BHP/L). R Ford 5.0 would easily put out 280 (56BHP/L)

Am I missing something, or are these engines just not particularly volumetrically efficient? Please believe that this is NOT a troll, I just haven't been able to find out any definitive answers.

[sharkey]

RE: 3400 250HP Naturally Aspirated?

the numbers you have are for an early 3100 motor. a 3400 is 185hp/ 205ft/lb torque making it 54BHP/L. now hp/l isnt a real good way to compare motors.

[enderw88]

Thanks!

I pulled the numbers I used from the family tree on this site (typoed the torque, it say 180ft-lbs, but the 3400 F-Body quotes 160HP). They seemed a bit low.

The specific output is not a good way to compare engines, but the number is a good measure of the basic maturity of the design. If you look at specific output from engines going back over many years you will generally see it slowly increasing over time. That indicated that the engine technology is improving. You should expect to see carbureted N/A engine with speific outsput in the mid fifties (exactly what we got when yu gave me better numbers). If you look back in the sixties you would see them being closer to the mid forties, except for very large displacement engines. Modern FI N/A engines should see 65+BHP/L. If you see a performance engine that departs wildy from the specific output typical for the era it is indicative of poor design, or being optimized for a different use. Specific output is also a good way to estimate what you SHOULD be able to get out of a motor with appropriate modifications.

[smilinguy99]

You are correct sir. As much as I like the GM 60 degree V6, virtually all of them are underachievers in production trim. That includes the DOHC versions as well.

I'm not familiar with the BMW motor you speak of. I assume it is a four-valve motor? The pushrod 3400 is a two valve machine.

It is likely the motor could make 200+ without much trouble. Just fabricating a decent set of headers would unlock quite a bit of potential. The factory exhaust manifolds are designed with packaging in mind rather than efficiency (something that would no doubt make a BMW powerplant engineer quit in utter disgust.) The manifolds are shockingly small and appear quite restrictive. But they don't take up much space and therefore permit the motor fit in virtually every domestic engine compartment.

GM appears to be in continual development on this motor. They keep making changes that would seem to enhance durability as well as output. Heads (bigger valves and ports), oiling system (centralized galleys), journal sizes (larger), and rod length (longer) are some of the recent 3X00 changes.

There is a company http://www.killerbv6.com/ that sells headers for the 3400 as well as RWD conversions for this motor. The 3400 and all other aluminum head motors come from the factory only in FWD applications.

But overall, aftermarket lovin' has largely passed the 3X00 motors by.
I understand CompCams was considering making cams for this thing with the SYNC signal ring for the ECM. I don't know if they did or not.

There is another way to think of this motor and its contribution to performance. The motor would help shift the CG slightly rearward and down as opposed to a straight six.

No doubt the Stalker folks chose to recommend the 3X00 because of its availability and its compact size. It really isn't much bigger than a 4cylinder. The block is only about 17.125" long and weighs 106lbs, but there is a rather expensive aluminum racing block that weighs 58lbs. Using this block would make Colin Chapman look down and shed a tear of joy.

Where are you located and how available is this motor there?

sg99

[RebelGT]

I know Brunton hasn't tryed it, but I'd be interested to see if the DOHC would fit in his stock chassis width. I'm building a locost from scratch using the DOHC, so I'd just be interested to see. You might also want to PM kreb, he has built one of the stalker kits, he might be able to answer any other questions you have.

[TurboZ24]

I've actually looked at the StalkerV6 setup and considered pulling the engine out of my car and placing it in there. As for what is possible with the 3400, GM did have the Beretta Convertibles with a 225 HP 3.4, it never came into production, but obviously it's possible. Also, Colin is running a 13.99 ET in his 3.1 NA Sunbird with a 3.1/3100 hybrid, so I'm sure it's over 200 crank HP. I have seen NA 2.8's reach 280-290 HP levels, but that's with 12.5:1 compression, cams so aggressive they hardly idle, etc.

[GinoBeats]

I should have dyno numbers of my full build within a few weeks.

[Doubt_Incarnate]

I have seen NA 2.8's reach 280-290 HP levels, but that's with 12.5:1 compression, cams so aggressive they hardly idle, etc.

Darn, my goal is for a near 300hp aluminum rwd NA 2.8 with the 3400 heads. but i'd really like it to idle. Looks like i'll have to look into some fancy "V-tech" like intake crap, or some other trick to get more top end power out of a 2.8 that can still idle.

[Kreb]

Hi. I've got a Stalker. I think that Dennis Brunton specs the 60 degree pushrod because it's cheap, reasonably well performing, and very compact for a V engine. While HP figures are nothing to get excited about, torque isn't bad, and that's a lot of what makes the car such an auto-X demon. Inexpensive parts are also as close as your neighborhood discount auto supply.

DOHC will not fit under the hood. You'd have a serious lump that might look fairly crappy. On the face of it, the 3400 would be preferable to the 3.4/3.1/2.8, but it won't fit with the stock intake either, and you have to accomidate the reverse side starter and what have you. I only know of one guy who put a 3400 in a Stalker, and it's been a struggle.

Enderw88 - If you live in a location that doesn't have easy access to our 60 degree V6, and you have the fabricating skills, I think that a BMW inline 6 would be a killer engine for a Stalker. Perhaps a bit heavier, but smoother, more refined and all sorts of available speed parts.

OTOH, if you just have a 210 ft/lb. 180 HP motor like mine, you'll still find the Stalker to be amazingly fast with only 1400 lbs. to push around.

[geoffinbc]

enderw88 180lbs is not a typo on the Camaro motor. That is the rated torque. I originally though it was 160 aswell but was told I was wrong and changed it to 180lbs.

HP numbers are low for these engines because they are designed in true North American fashion. Low end grunt. If you wana make em spin you can. Put in a big cam open up the exhaust and intake and spin her up to 7000. It will do it with the right combination of parts. Just ask the miget racers.

[enderw88]

enderw88 180lbs is not a typo on the Camaro motor. That is the rated torque. I originally though it was 160 as well but was told I was wrong and changed it to 180lbs.

I meant that I quoted the torque incorrectly when I wrote "170ft-lbs" in my first post.


Kreb, thanks for the response. It would be interesting to put a modern BMW six in there. I don't think my fab skills are up to it and the motor is actually quite long. From perusing engine bay pictures of Stalkers I don't think it would fit without moving the weight bias significantly forward, and it may not fit at all...

Smilingguy99 I checked out the killerb site and they have some very good deals. The engine is probably reasonably available here in Tucson, but I am leaning towards a fresh motor simply so that I have a good baseline.
You comments about the headers are the most enlightening and would go a long way towards explain the low volumetric efficiency. But trust me, BMW engineers do silly things too! Everything I need to get to seems to be behind something I can't move. I have a 97 Z-3 with a 2.8L six, and the engine bay is just about solid engine. It really isn't too bad for standard maintenance but the 24V with variable valve timing essentially mean it is a rolling computer and beyond my capabilities to do much with...even though I do have code reading tools. There just isn't much to tune, it just works.

[Bratok]

mildly modded 3400

[vsop4me3.1]

mildly modded 3400

221@3800 tq
187@5000 hp
what mods do you have? to give us more of a broader view, please.

[xonelith]

I have the 3400 with a Milzy Motorsports setup and dyno'd 203 HP at the wheels. This was a fairly cheap modification (as modifications go). Also full exhaust & headers.

As you can see, it is possible to get 250 (crank), probably not practical

[Bratok]

221@3800 tq
187@5000 hp
what mods do you have? to give us more of a broader view, please.

# JBP mild reground cam
# RSM Racing ported UIM
# RSM Racing ported LIM
# FDP 62mm Throttle Body
# NoyzBoyz CAI
# Some chip tuning