Highest Performance G50...? Anyone build one to compete with a V8 E39 M5?

[supermoose]

Had a run in on the freeway with a modded E39 - exhaust, wheels, lowered, probaly dinan exhaust, pulled several good passes between 85-140mph, the Q quite suprised me. I wasnt in his league, but i'd stay within range and catch up in traffic, kinda like how you can catch up to faster cars in open track days due to traffic and then you break out and dogfight it again....

Main advantages of a E39 M5 - Shorter gearing - 6mt is so fast to response with acceleration, id floor it and my 4eat trans would shift to 6,000 in 3rd - TC lag is so evident, M5 was already well into acceleration when the trans of the Q reacted. Need a 350Z 6mt, or a z32 5mt with boost. 4.08 FD as well would give it a chance. At 6700 rpm or so the Q45 actually gained a little on the M5.

Footwork is not that stable above 130mph - M5 is HELLA stable. my q is running stock dampers and springs but pillow ball front links, tie rods, frame spacer in rear. It's great for what it is, but at 130 its simply not stable. Are there availible dampers that can handle high speed stability- i.e. PSS9 would be great if it existed for G50.

Need some wheels to handle it. 18x8.5-9.5 or so should do the trick. i dont know tire sizing bc im a noob to the Q, but im guessing something big. Tires perhaps something that the euros like to spec, like Pilot's or something.

What is the highest NA output VH45 in a street car with no ITB's ?

[Rex]

Search for archived posts by rsiwicki, he built ons of the fastest, and has the numbers (1/4 mile, dyno and dollars) to back it up.

First things first

Make sure your knock and o2 sensors are in great shape.That your plugs and injectors are in top shape (CA gas is horrible to injectors).That the transmission has an external cooler, fresh fluid (w/ Red or Balck LubeGard) has been mechanically flushed and is shifting "like new". You'd be surprised how well it downshifts (to 2nd) and the car takes off ~75.Do you have the TCU to allow for 1st gear starts?How fresh are your shocks and struts? FUCA's? Tension Rods? Sway bar bushings?Do you have both front and rear? From an active?What about a FSTB (Jeff Williams style )

If you or the previous owner haven't spent $5-7k in the last 2-3 years, you're most likely not drving a Q that's up to stock potential.

Q's, cheap to buy, expensive to maintain, bank breakers to make faster

Wes and superuber has NOS, so that's option, but you'd still want to address the above items.

[Rex]

Need some wheels to handle it. 18x8.5-9.5 or so should do the trick. i dont know tire sizing bc im a noob to the Q, but im guessing something big. Tires perhaps something that the euros like to spec, like Pilot's or something.

What is the highest NA output VH45 in a street car with no ITB's ?

I have forged 18x9's +35 all around on my Q (formerly Rob's - rsiwicki), they cost me more than 1/2 what I paid for the car, and he sold me the car at a HUGE loss. With 245/45/18's they barely clear, and actually rub the front (plastic) inner liner over big dips at speed

BTW, he provided me with the dyno sheet showing 275hp / 285TQ at the rear wheels.

[DrewQ45]

No mention of FSTB or rear sway bar? Without these you've got nothing.

...Drew....

[supermoose]

have those both. dont do very much. my 50K mile JDM trans has an oilcooler and its slow as hell in comparison to any high end GM automatic. the geaering is spread out too wide too. VH doesnt make That much torque. MY q also has the upper SPL link and lower tie rod and the nico/JWT ecu and Apexi' bigass airfilter. not enough to match 5 liters with vanos and 8 ITB's. not happening.

Without Serious modification, the Q45 will NOT be close to an M5. 275 wheel isnt that impressive, as a M5 is bone stock 400 crank.... we're not shooting to play with civics, we're pondering the idea of attacking the best built german luxury highway monster. I've gone 6 laps wheel to wheel with a V10 M5 at laguna with my Sti and know what it takes to pass one of those- the v8 isnt much slower, but the M severely modified has a chance at it.

I'm driving the holy hell outa the Q. I went on a mountain pass and chased my Sti-RA with my buddy driving it, the subaru does ~ 1:48 at laguna with street tires and stupid me drifting it ;P - 330hp crank, 8500 rpm redline, 13' brembos all around, rally gearbox, 2600 lbs. IF driving the Q all out can be summed up, it does keep up.... barely :P

for referance some random LS lap times

Porsche 997 Carrera S 1:50.0EVO 9 - 1:48

E39 M5 does 1/4 mile in 13.2

my subaru is a 12 second car. im assuming a e39 M is a 13 second car, but do any Q45's do mid 13's NA?

as a performance car, the G50 platform is pretty suprising, but the limits do come.

Modified by supermoose at 10:06 AM 6/27/2007

Modified by supermoose at 10:10 AM 6/27/2007
Modified by supermoose at 10:30 AM 6/27/2007

[ScottJackson]

I hate to say it, but without boost or nitrous, it's not gonna happen... short of boring the motor and installing larger sleeves, stroking it with custom internals, porting the heads, regrinding the cams, yadda yadda. On my E34 540i, I have 265/35-18 tires on the back and there's room for bigger ones. The wheel wells of the Q aren't nearly as wide. My 540i is bone stock and it is a little faster than my '93 Q. The Q has tokico blues and my 540i has KYB GR-2 struts. The KYBs are a bit more harsh than the blues. My Q is very stable up to the 140mph I take it every now and then. My 540i is even more solid feeling. The E39 M5 isn't much faster than the E39 540i with 6 speed. The 540i is much cheaper to buy and when you add a supercharger kit, you can outrun vipers and vettes. I think the Q is great for freeway cruising and maybe some high speed cruising, but it's not a thrill to drive by any means. It sounds like you want something more sporty. If you're on a bit of a budget (who isn't?) then my vote would be for you to either sell the Q (too bad they don't sell for anything) and buy a 6 speed 540i, or keep the Q as a cruiser/grocery getter and get a 6 speed 540i to pimp/modify. The Getrag 6 speed in the 540i will hold over 1000hp (basically same trans as what's in the MKIV supras) and the rear end is equally strong. The engine internals are good to 800hp. I personally am keeping an eye out for one of these which needs work (because I'm poor and that's the cheapest way to get one). However, my mustang project is finally starting to come together with its 514" big block and R154 toyota 5 speed. That should put about any M5 to shame.

[supermoose]

the idea is:

will a camm'ed (im guessing indycar) VH45de make enough power to keep me in sights of tailights?

how much power can i make NA to try to chase a E39 M5 if i stuff in a 6mt and some killer footwork (probably custom spec some PSS9)

I've been pondering the 540 6mt but would really like it in a wagon...... :P

[ScottJackson]

Maybe. If you get the cams reground and better valve springs, you won't be too terribly far down on power compared to the M5. Get some gears for the Q also and you can probably at least keep the tail lights in sight... on a clear night If you do the manual trans swap, take lots of pics and post it up here. I think the E39 M5 was a bit over rated on power and the E39 540i a bit under rated. Are you sure the car you were running with that was modified was a real M5 or might it have just had the M5 badges (540i with wheels, exhaust, badges)?

[Rex]

Am I missing something here?

According to BMW, the E39 540i (not M5) has a claimed 282hp (crank #), though it does weigh ~400 lbs less and has a MT, it shouldn't be that much faster on the open road. From a stand still by all means, but if you can find the "sweet spot" in 2nd gear for you (2nd gear will go all the way to ~95 mph), so look dropping the hammer when doing about 75 and see if it downshifts all the way to 2nd. Also, find out when the E39 is "between sweet spots". The idea is you should be at a speed that's good for you, but not for them.

All that said, I think to hang with a 400(crank)HP M5, most of which the owner hasn't left stock, is going to take either FI or NOS.

[ScottJackson]

Yeah, the 540i E39 regularly dynos at 260hp at the wheels. It was definately under rated by BMW.

and 400lbs difference is a lot. I had 3 passengers in my Q the other day (prob about 500lbs worth of extra weight) and it absolutely KILLED the acceleration of the Q.

[supermoose]

car was geared with a 6mt, so i suppose could be modded 540 or M. it pulled like a high revving NA motor though, and all the bodywork was M. sounded like M too.

sweet spot in 2nd gear isnt useful if im racing from 95-130 all the time. Q feels really painful to shift that hard, i feel bad abusing the car as thus.

6mt would be ideal, would have to have some serious boost for a 5mt to be really effective- extra weight too much for the tires and torque curve would be unstable in comparison.

the only question i have for 6mt right now is how to mount the silly thing, they're cheap enough to come by ~$350 on fleabay, and the bellhousing modification for the 5mt can probably be done on the 6mt for niot much more. i figure if i drop $2k into it, i can probaly score a 6mt in my car.

I'm all about cheeting on logistics to win, but like we say about subarus - fast cars dont need to downshift to wangan battle....

It's going to take more than just power, the 4000 lb weight needs some serious footwork evolution

Modified by supermoose at 11:00 AM 6/27/2007
Modified by supermoose at 11:01 AM 6/27/2007

[Rex]

Scott I understand 400 is alot, at take off, but it shouldn't be nearly as prohibitive when rolling at ~70, as you can get into the tq band so much easier, unlike s standing start. I mean it's still 400 lbs, but I think the bigger issue is speed/gearing at start of "encounter".

... I'm racing from 95-130 all the time. Q feels really painful to shift that hard, I feel bad abusing the car as thus.

6mt would be ideal, would have to have some serious boost for a 5mt to be really effective- extra weight too much for the tires and torque curve would be unstable in comparison.

the only question i have for 6mt right now is how to mount the silly thing, they're cheap enough to come by ~$350 on fleabay, and the bellhousing modification for the 5mt can probably be done on the 6mt for niot much more. i figure if i drop $2k into it, i can probaly score a 6mt in my car....

If that's your target racing speed, that sounds like your best bet for leveling the playing field. And if you come up with a $2k solution to putting a 6MT in a Q, there may be a few takers, not many, but a few.

[supermoose]

man. why is the Q so fun. had a encounter at lunch with new 645i convertable, seemed like an automatic. that thing is nicely setup and fast too. went balls out from 80-110 or so. that was fun. Seemed like he had a gearing disadvantage and shiftpoint sluggardness though from how he was sluggard off reaction in comparison to the E39M

Very funny, i just did a search. see how these stats seem very very familiar

Weight: 4001 lbsFR Configuration 4.4 Liter V8Valvetrain DOHC 4 Valves / CylinderDisplacement 4398 cc / 268.4 cuPower 248.3 kW / 333.0 bhp at 6100 rpmTorque 450 Nm / 331.9 ft lbs at 3600 rpmBore 92 mm / 3.6 inStroke 82.7 mm / 3.3 inCompression Ratio 10:1Bhp / Liter 75.72 bhp

***************************************************

i think a 6mt under 2K can be done.

i was pondering...

GTR 4.08 - figure out if GTR drivesahft is same length. GTR driveshaft would save hassle of swappign flange on gtr diff to g50 and gtr driveshaft slides right into 350z 6mt, so the only thing would be the length and position of the centre bearing, BUT if needed can always 1-piece driveshaft it.

6mt needs a crossmember of some sort, nobody who has done 5mt VH45 has done it with a G50 yet, at least not with the shave bellhousing style direct bolt up with z32tt clutch set, all have been done in 240sx's, so the X member still needs to be developed. Also the 6mt mounting may not be compatible with 5mt trans mounting, will have to check on that.

i suppose a light flywheel would be in order, hmm - i wonder if Z32 and 350ZX clutch are interchangable- bc then we'll have other problems with bolting onto VH45- Does anyone know how a 350Z 6m5 would be fitted into a z32tt?

Modified by supermoose at 2:04 PM 6/27/2007

I'd argue that engine vs engine, VH45 is not arguably worse than the 540's 4.4. M5 no way without boost, 540 - perhaps on par.
Modified by supermoose at 2:48 PM 6/27/2007

[ScottJackson]

I think engine vs. engine, the first gen Q has the better engine. Give it more cam than the M5 V8 and I think you could probably hit the 400hp number. A little compression bump would be a nice compliment for better torque. Other than the cams, I think the only thing holding back the VH45 is the tight torque converter and weight of the Q. The 4.08 rear diff won't help for higher speed stuff. It only helps right off the line. I swapped my 2.81 diff in my 540i for a 3.91. I lost some fuel mileage and it only helped a little from a complete stop. It shifts out of first gear so quick now that I actually regret the gear swap. I just wish my 540i had the 6 speed. The price of the 6 used is around $2500 so it's kinda prohibitive. I was going to just sell the V8 out of my 540i and swap in my 351C (may still do it) but the prices for those motors have dropped more like a rock than Bob Seger album sales OR chevy trucks. Still, I hate how the auto in my 540i shifts and the motor seriously lacks power for the fuel mileage I get.

The VH45 block is stronger built than the BMW block. If I were to pick one for modifying, it'd definately be the VH.

[supermoose]

hmm. so you would go close ratio gears with long final drive. hmm. not a bad idea, i guess it depends on the speed range and engine rpm where power exists.

anyone know anything about those indy cams.....

[maxnix]

anyone know anything about those indy cams.....

The Indy engine was severely destroked. Bet it didn't idle below 2500 rpm and the power band was 9K-11K rpm. Totally useless on the street.