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Micke · Post by **Micke** » Thu Jun 09, 2005 12:09 pm

I agree 45 would probably be better. However, I'm (as usual) playing a low budget here and if I go single TB's I have to use either 48 or 40 mm carbs I have left over.
I'll probably go for the single TB anyway (KISS)

O' the fool stuff - that was just to amuse you guys!

Maurizio · Post by **Maurizio** » Thu Jun 09, 2005 12:41 pm

the TS with std valves? 18,000rpm

Hmmm, I already regret I lightening the crank and fllywheel probally to much

Ok, here is what I got offered from alfaromeo-nockenwellen.de
regrinded standard TS cams to:
- inlet: Rally 306° 11,55 mm
- exhaust: Straße 284° 10,33 mm
This all should still work with the VVT which is good for emission.
(OK, Mats I know, license plates )
CR goal is 1:11.5, need a (larger diameter) good intake, and take two original TS TB's, custom exhaust, bigger injectors and a motormanagment. Head is ported adn origional valves.

Is this a nice concept, don't need a killer a sniper is OK.

PS. Do I interpret the cam specs right?
Cam profile of the intake cam:

So if I interpret the cam diagram good:
the 306° cam at 1.25 mm of the seat is ~ 120° cam speed is crank speed * 0.5 result >1.25mm for 2x120°=240° and for the 284° cam also ~ 240°

But bottom end first and then its time for some driving with the rest still stock! This project keeps on growing

Micke · Post by **Micke** » Fri Jun 10, 2005 12:52 am

Same place I bought my cams from. Decent price for new cams. My specs are a bit different though.

"and take two original TS TB's"
And this you don't call a killer???

Jim K · Post by **Jim K** » Fri Jun 10, 2005 1:08 am

Hahah! These is what I call Godzilla cams!
Jim K.

Micke · Post by **Micke** » Fri Jun 10, 2005 1:12 am

Yup.
Let's see how or if they work. If not, there's enough meat to grind ANY other serious profile on.

Maurizio · Post by **Maurizio** » Fri Jun 10, 2005 1:25 am

"and take two original TS TB's" And this you don't call a killer???

Your cams are for a killer, mine for a snipers.

Also low budget here, this is what I've got laying around, but probably a V6 tb (3.0 vs 2.0) would provide enough air).
Hmmm thinking of it I've got also a spare motronic V6 AFM.
From larger custom plenum, larger\longer intakes to original injector plate and a good 4 - 1 header.
Remapping the motronic to my engine specs would do the trick, simply said

Jim what do you think?

Micke · Post by **Micke** » Fri Jun 10, 2005 2:20 am

I'm sure your cams will be perfect for your engine. Makes no sense overdoing it.

I don't have the calculations here now, but maybe someone else can tell what's the power limit for one TS (70 mm) TB? Waaaaayyyy abowe the range we're aiming at.

I'd say, use one TB and make a decent plenum for it.

What you need to keep in mind is that you might run out of injector capacity.

Mats · Post by **Mats** » Fri Jun 10, 2005 2:22 am

Eh, those cams are finish ground?

TWO 70mm TBs?? talk about on-off gas pedal... the standard setup on the TS is INCREDIBLY oversized imo. The TB from a Delta Integrale looks like a toy if you place them side by side, and you want two of those? why..?

Micke · Post by **Micke** » Fri Jun 10, 2005 2:26 am

"and you want two of those? why..?"

Easy:

BIGGER IS BETTER!!

Maurizio · Post by **Maurizio** » Fri Jun 10, 2005 3:11 am

This is engine modifying stuff is all new to me, would love some input on how to calculate this kind of stuff! (a theoretical book, I know I'm asking for trouble

)

Injectors are good for ~175 hp (have I heard) so need bigger, to go on the safe side.

Mats · Post by **Mats** » Fri Jun 10, 2005 3:22 am

Mean airspeed over the TB is one parameter I guess but the problem with a very big TB (or two) is that you open up a very large flow area even with a small pedal movement.
If the engine can only suck in a certain amount of air and that air can flow through the TB even if you only open it 10 degrees everything over 10 degrees is just useless pedal travel and the first millimeters of pedal travel is idle to full throttle... Difficult to drive maybe? Playstation gas, digital buttons.

The 75 Turbo has two TB's in the same housing, one small that opens almost fully during the first half (or so) of pedal travel and one seconday TB that is larger and quickly swings open during the second half of pedal travel.
Probably there were a large amount of rubber-band effect driving it with only one large TB. You press down 5mm on the pedal and after the turbo spools you need to lift off meking the car go to slow, you press down 5mm againn to spped upp - turbo spools.... and so on. I tried a friends tuned turbo Saab a while back and that car went crazy if you activated the cruise control because of this rubber-band effect, guess the regulating circuits wasn't really tuned to handle the new brute force...

Do that German site have TS cams btw? Looks like nord cams only? No V6? Good guys to deal with? Cams are on spec?

Maurizio · Post by **Maurizio** » Fri Jun 10, 2005 3:42 am

I mailed the guy a year ago and he suggeted the posted cam combo (a regrind from TS cams) . So he can make TS cams.

Dennis · Post by **Dennis** » Fri Jun 10, 2005 3:51 am

Dammit, we need Jims TS supplement here. Much easier to choose cams when it's listed in a book

Maurizio, have you found the right combo of piston and rods?

Maurizio · Post by **Maurizio** » Fri Jun 10, 2005 4:18 am

@Dennis see < Engine ~ TS bottom end rebuild

Jim K · Post by **Jim K** » Fri Jun 10, 2005 8:47 am

Maurizio, the cam drawing you have posted, shows a duration (as close as I can measure from it) of ~246* @ 1,25mm, compared to the actual 230* of the 105.48 cam (yellow color). This a very mild cam, I wouldn't even call it a rally profile, more like a fast road one. Its also a dated design. Modern cams, have high accelaration ramps and very low running clearance. This results in less actual duration, leadind to higher compression pressures accross the board = more torque! If you want to see a very good (bordering on extreme) cam profile, have a look into an F3 design. There you'll see how things should be. Of course, there are mechanical considerations which do not allow widespread use of such profiles, but the path is beaten. A modified F3 profile is an excellent choice, exactly what a number of cam makers have done for many of their profiles.
Jim K.