I wanna de-stroke a 3.8

[Dr Goggles]

Hi Guys, I'm new here....I come in peace, not necessarily bearing gifts but maybe just a few good stories.....Ive always been a Holden guy.
We run a Bellytank lakester in the Dry Lake Racers of Australia and may be able to lay claim to Australia's fastest Commodore V6 motor , this March just gone I did 310klm/hr or 193mph at Lake Gairdner in Sth Aus.

It took us five years to build, we built just about every single piece in my little garage with bugger all , but it ain't no show car.....it's just a really big go-kart with great aerodynamics and a super-rigid frame.For instance I made this twin TB manifold...

The first year out we ran 160mph with a VP motor, a shortened Aussie 4 speed and a 2.77LSD out of an XE 6, the donk had done 330,000k's out of a one owner Berlina.This years motor was Scott Taylor's old "Turbo VN" bottom end with the heads we'd used the year before and a fairly long duration cam. The lifters started pumping/collapsing at about 6275, that translated to 195 mph top speed the best average mile was 193. I've just bought some stage three heads done by Trick and Mansweto which we'll get some solids to run. We've also got a US 10 bolt rear end with a Torsen centre coming which will allow us to go down through2.73,2.56,2.41,2.28 and 2.14:1 ring and pinion sets but my suspicion is we'll never get past 2.41:1.

The year after next we'll go to an Eaton blower that we have, by that stage we hope to be up in the 225-230mph range.

We run in E class which is 3.0 to 4.3 litre. When we get up beyond 220mph we'll be hitting the affordable limit for us.....so....here's my question.

I'm thinking about de-stroking a 3.8 to under 3 litres. What I need to start my research is a good blueprint of the early cranks the VN and the VP with accurate measurements. If anyone knows where I can find one it would be much appreciated.

Thanks guys, I look forward to my time here and any help I can get to knock this over.

 

[ephect]

wow thats quite impressive.

any engine specs and setup that you can divugle?

in regards to de-stroking, the only option i can think of is cylinder sleaves and smaller pistons, which would all have to be custom. that would be the best option, allowing you to use the same crank you may have to get heads to suit made.

 

[Dr Goggles]

piston speed

Na , dropping the bore ain't it...a shorter stroke gives us lower piston speed, less rod angle ,less rotating mass and a lower swept distance which all mean more efficient higher revs...expensive, some would say pointless but for what we're doing making power at maximum revs is what it's all about .

......As a friend in the US who has run 300mph says..."in landspeed , he who fires his sparkplugs the most times wins"

This years motor had a Wade 1365a, the twin throttle body high rise manifold, 9.6:1 comp, ACL pistons , deleted balance shaft, balanced crank, billet flywheel, heavy crow springs, a port job and our own headers. We got a couple versions of the chip..a "burnout" version and one that Jason Clark mapped for us based on the motor specs...we didn't have time to dyno the car this year.

 

[Not_An_Abba_Fan]

Balance the whole rotating mass as one unit, remove as much material from the crank and pistons as you can to make them lighter, but having a perfectly balanced setup is the key. Lightened flywheel, balanced tail shaft, even the gearbox.

Solid lifters and roller rockers may help to give you higher revs too.

 

[Immortality]

they produced a 3.0 liter version of the V6 for the US market in the 80's check here for info Buick V6 engine - Wikipedia, the free encyclopedia

there are guys turning the V6 engine to 7000rpm so with a decent solid setup you should still have more revs from it

 

[Dr Goggles]

solid Bro

Balance the whole rotating mass as one unit, remove as much material from the crank and pistons as you can to make them lighter, but having a perfectly balanced setup is the key. Lightened flywheel, balanced tail shaft, even the gearbox

The flywheel ain't that important because we don't need fast response and the revs are building slowly, but you're right , a lot of energy is lost by minor balance imperfections at high revs. We only have a two inch tail-shaft.

they produced a 3.0 liter version of the V6 for the US market in the 80's

We want to use the same block architecture, the 3.0 was a pretty different motor from what I can see, might be wrong. It's so we can use the same heads.

People are always trying to get bigger flowing heads , to make more power.If you put your heads on a smaller motor in effect you're doing the same thing, not more power ...but more than what you had. We are interested in going DOWN a class, that means below 3 litres but hoping to use everything we have developed for the 3.8 and then de-stroking to give us the associated benefits. It is very uncommon because it has little to do with what people are usually chasing.

A guy who has been a lot of help to us in the past who ran Buicks in the states has done a similar thing.....his first example was whehj he built motors for don Vesco's Kawasaki powered streamliner in the seventies, he used everything from the 1000cc motor except the crank and rods which he got from the 750, then built the motor to sit under the 750 class limit, "made alot more power than their( Kawasaki's) 750" he said, and true, it set records.... The other thing he had a thing for was not getting carried away with comp in REALLY hi-revving motors.

there are guys turning the V6 engine to 7000rpm so with a decent solid setup you should still have more revs from it

In it's previous incarnation Scott Taylor turned this motor over 7 many times on the quarter, this year we had a pissy valve train ........it's a case of step by step..

Solid lifters and roller rockers may help to give you higher revs too.

Got 'em, just need to get a proper solid profile cam to go with 'em....


So, anyone wanna buy a Wade 1365a camshaft that's only done about 30miles?

 

[delcowizzid]

there are a few different balance specs for the v6 depending on its use somewhere around 36% on the street, 50% with solid mounts ,and for high rev applications theres an overbalance of around 67% to open up topend.i thought the us guys had a 3.0 like immortality was saying based on the same form of block i see maybe swapping the crank out into the 3.8 if its a destroked version or if you want to destroke a factory crank use the usa oddfire crank which has shared journals for 2 rods at a time so meat can be removed to destroke them

 

[Deltak]

Hi The Yanks made 3.0 liter version of the Buick V6 as detailed below.

"A small 3.0 L (181 in³) version of the Buick V6 was produced for GM's 1980s front-wheel drive cars. Introduced in 1982, it was a lower deck version of the 3.8 designed for transverse application in the new GM A platform cars such as the Buick Century and Oldsmobile Cutlass Ciera. It shared the same bore size as its larger sibling, but featured a smaller stroke of 2.66 in (67.56 mm). Introduced with a Rochester E2ME 2-bbl carburetor, it later received multipoint fuel injection.

Year Horsepower Torque Fuel System Compression Ratio VIN Code Applications
1982-83 110 hp (82 kW) @ 4800 rpm 145 lb·ft (197 N·m) @ 2000 rpm 2-BBL 8.45:1 E 1
1984-85 110 hp (82 kW) @ 4800 rpm 145 lb·ft (197 N·m) @ 2600 rpm 2-BBL 8.4:1 E 1
1985-88 125 hp (93 kW) @ 4900 rpm 150 lb·ft (203 N·m) @ 2400 rpm MPFI 9.0:1 L 2
Legend

1 - 1982-85 Buick Century, 1982-85 Oldsmobile Cutlass Ciera
2 - 1985-87 Buick Somerset, 1986-88 Buick Skylark, 1985-88 Oldsmobile Cutlass Calais, 1986 Oldsmobile Delta 88, 1985-87 Pontiac Grand Am
(Wikipedia)"

You could use the 3.0 l crank from one of these and just use longer conrods to bring the piston speed down.

Just a thought.

 

[Dr Goggles]

yup

That's more like it, I found this out a week or so back, we'll go for one of those 181ci cranks the class capacity break is at 183ci.......I'm starting a search on US eBay and the HAMB.

On another front I spoke to Mick at YT today and have decided to go with some LS1 style rockers , we need adjustables to cope with the solid lifters , we're going with a Wade 1644 cam too.

There's another little feature on our car in the upcoming edition of Fuel mag...

http://www.fuelzine.com/issue-04

 

[Immortality]

just saw a artilce about the salt racers and this car in the latest Street Machine mag :thumbsup:

how much you want for the wade cam? profile doesn't suit me but it might for a re-grind