GRiSO 1400

Bigger Block 8V

The idea of putting a 1400 top end on an 1151 bottom end had been in the back of my mind for a couple of months. A thread on another forum prompted me to put the question to Pete.

Yes, was the answer.


So, using my bike as a platform, Pete and I are going to build a GRiSO 1400 VSE (Very Special Edition).
1400 barrels and pistons, 1151 heads (roller) and our way if tuning.

I'm not expecting a Tuono beater, but I do expect a massive increase in torque.

Over to you, Pete.

Cali 14? Single 52mm TB plus plenum plus cleverer 7SM controller and RBW.

GRiSO two 50mm TB but more primitive and less sophisticated W5AM controller.

X sectional area of intake tells part of the story. Pi x R2 if you've forgotten since leaving school.

Think about that for starters. I'll throw in a downside next after this has been discussed.

Pete

I cunt wait to see this!

Would love some pics, video if possible w/ audio .

Good luck. [You must be registered and logged in to see this link.]

I'm pitching a tent here

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I want to be on the list for when these "RoBeetle" 1400 kits can be ordered!

I totally agree with the "Robeetle" concept, tocino! I'm curious to see what the overall

weight of this new pedigree might be? Regardless, kudos for pushing the limits, guys.

We will find ourselves in GRiSO nirvana soon enough with you two at the helm!

You really don't like rear tyres do you

Ain't no substitute for cubic inches.
(At least that's what she keeps telling me)
Watching with interest.

The smaller inlet of the 1200 means higher inlet velocity. As we are using the 1200 heads, there shouldn't be any reversion issues.

How do the valves and inlet ports on the 1400 heads compare to the 1200? Larger? The same? Can we get enough VE? Off idle torque will be less I suspect (or at least no better). Top end will be marginally better.

I'm thinking the benefits will be in the 3500-6000 range.

I'm going to have to do some cross referencing of stuff. I think the porting etc. is the same but the valves are probably longer due to the extra depth of the 1400 heads to accommodate the larger cooling galleries. Apart from the low RPM surging issues the other big benefit of the extra plugs, (And most likely the reason they are dropped out above 4.5K.) is to maximise cylinder pressure at low RPM. One thing that the Cali does spectacularly well is pull like a Burrel Road Locomotive straight off idle, it's also probably a reason why they re-inserted the face cam shock absorber in the gearbox, so the 'Potato-Potato' brigade couldn't destroy them! the other advantages that the Cali 14 has is the intake plenum and the 7SM controller but we can't have everything unfortunately.

Pete

tocino wrote:

I want to be on the list for when these "RoBeetle" 1400 kits can be ordered!

No 'Kits' required. This will all be done using 'Off the Shelf' parts and should be applicable to any 8V 1200 not just the GRiSO.

Pete

With the 5AM, we won't be able to control the spark like the 7SM can, but the 5AM ain't no Abacus either.

I have some ideas.

I've got most of the order made up but there are a couple of bits, (THe tensioner plug for the RH cylinder and its sealing washer.) that aren't up in the system in Sydney so I'll wait until Monday. The kicker is that barrel and piston kits are nil stock in Oz and it's now August so nothing will be leaving Italy until early September. Grrrrr.

Pete

That gives me plenty time to finish Len's map. Shall we rollerize as well?

Given the fact that you have to pull the swingarm and semi-crab the frame to get the barrels off without removing the studs, (And maybe even then, I haven't tried it yet.) it would be insane not to do the whole box and dice at the same time.

Pete

Noted.

nice project, can't wait to see/hear/ the result !

And the thing is if it turns out to be a complete disaster? We'll own it. We won't lie and bullshit about it.

We are certainly not expecting a huge amount more power, that isn't the object of the excercise. To get that would require not only different cams, (I know absolutely nothing, nada, zip, about roller tappet camshaft profiles or any aftermarket company that grinds them.) but expensive, time consuming and possibly destructive work on the heads. Also there are a dozen bikes in showrooms you can buy that make a shitload more power if that is what you crave.

The principle objective in to increase torque and while we probably won't be able to get the stump pulling bottom end of the Cali 14 without the extra plugs we'll give it a damned good shot and I'm expecting substantial gains in the midrange.

Torque is force times distance. Since we can't increase the distance from the axis of the crank without changing crank and connecting rods, (And on a Hi-Cam or overhead cam engine this presents a whole raft of other issues!) we are limited to increasing force and this is what big boring does. Apart from the increase in charge the increase in surface area of the piston means that greater force is exerted on it by the expanding gasses. The trick will be to achieve the best cylinder fill and most complete combustion of the correct mixture.

We know the stock airbox works OK, anyway, there's no space to enlarge it! The stock filter will flow more than enough air and we've established what pipe configuration works best with the GRiSO's exhaust set up. We may need to fiddle with some things but most of the groundwork has already been done. Unless we are completely wrong about something the results should be most satisfactory and if they aren't, we'll tell you.

Pete

Pete, if you ever need to chew the fat on a few things regards roller rocker, cam timing, porting etc etc. my next door neighbor is Colin Lloyd of Headsense [You must be registered and logged in to see this link.] Spent a lot of time in his shed watching engine building and 1000hp dyno runs. Shakes the truck out of the whole complex.

While some of his work may be about full power at the drags, a lot of Cols work is still for road use and is based around things like lbs of fuel/hour/rpm/hp which is all about drivable torque and "efficiency".

Plenum chambers are accepted as a normal performance part of high rise manifolds on V8's, the other neighbor (RX Automotive) builds hot IL6 BMW M3 race engines and refuses to diverge from 6 separate inlet/throttle bodies. Col built his own IL6, the addition of a plenum (which was undersized due to room constraints) created a much smoother and lower idle speed, increase in torque, more hp continuing to higher rpm, and better fuel economy.

Anyhoo, if ya wanna chew the fat ...............................

Thanks Wayne. At the moment though I want to achieve the best we can without *Serious* modifications to cams and the like.

The other immediate thing is that I think there is some confusion regarding the difference between roller rockers and roller tappets. They are two entirely different things.

Petr

So the plan is to use Cali 1400 (1380cc) barrels and pistons on the 1200 (1151cc) 8V crank (same stroke) ?

The compression ratio is gonna jump bigtime using the 1200 heads with 1400 barrels. Additional thickness between barrels and crankcase or barrels and head might be required to maintain the existing compression ratio. The ripple effect continues into the length of the cam chains also.

Lotta ripple effects here gentlemen ..... but you're both old enough and ugly enough to know that

Already done the research on camchain length, bore and a host of other factors. One thing that does piss me off is the fact that people think I haven't thouht about stuff like this. I'm not an over-eager twenty year old ! I'm a well qualified and VERY experienced 58 year old with forty plus years trade experience. Doe's this mean I won't overlook stuff or make mistakes? No of corse not! But please give me credit for half a brain.

Pete

It's all under control Len.