Search found 538 matches

by Duk
Fri Apr 21, 2017 7:22 pm
Forum: Performance
Topic: Inlet Manifold Design
Replies: 125
Views: 66209

Re: Inlet Manifold Design

It seems like the Porsche Varioram is probably the most devoted variable harmonics inlet manifold. It uses 3 different stages of dual length and divided plenum chambers. Long runners/divided plenums, short runners/divided plenums and short runners joined plenums.
by Duk
Wed Apr 19, 2017 5:26 pm
Forum: Performance
Topic: Inlet Manifold Design
Replies: 125
Views: 66209

Re: Inlet Manifold Design

Dual length manifolds so seem more common on engines with fixed camshaft timing. But Toyota did use interlinked dual plenum chambers on some of its 6 cylinder engines, both straight 6 and V6 without any form of variable cam timing. And there was that Nissan engine I posted a pic at the very beginnin...
by Duk
Tue Apr 18, 2017 9:23 pm
Forum: Performance
Topic: Inlet Manifold Design
Replies: 125
Views: 66209

Re: Inlet Manifold Design

So giving this old thread a bit of a rattle............... What are peoples thoughts on the types of variable resonance manifolds and their effectiveness? For a pair rather different exampes, Ferrari went from its previous dual length manifolds in the F360 and F430 to its divided plenum chambers wit...
by Duk
Fri Apr 14, 2017 5:11 pm
Forum: Suspension, Steering, Wheels, Tires
Topic: Ackerman Angle
Replies: 5
Views: 3660

Re: Ackerman Angle

The idea is to have zero toe, as close to zero bump steer and simply run true Ackerman. The reason why I ask this question is because I want to increase the track width substantially. But I will be using +50 offset RX7 wheels and RX7 wheel hubs. These have a more central mounting face than the Alfa'...
by Duk
Tue Apr 11, 2017 12:31 am
Forum: Suspension, Steering, Wheels, Tires
Topic: Ackerman Angle
Replies: 5
Views: 3660

Re: Ackerman Angle

Hey KevinR, I don't have a standard balljoint to compare the long balljoint with, but I think it was close 25mm. The bump steer corection was done by using spherical rod ends. Their pivot point is higher than a tie rod end, so with a 5mm spacer I was able to get rid of almost all of the bump steer. ...
by Duk
Sat Apr 01, 2017 6:43 pm
Forum: Suspension, Steering, Wheels, Tires
Topic: Ackerman Angle
Replies: 5
Views: 3660

Ackerman Angle

When trying to figure out Ackerman angle, the diagram below is often the sort of thing that is used to figure it out. But the diagram only looks at the top balljoint or stut top and doesn't allow for the King Pin Inclination angle. Using http://www.Vsusp.com I modeled the front suspension of my 75 w...
by Duk
Fri Feb 24, 2017 7:05 pm
Forum: Other
Topic: Another Mad South African project - V12 Alfa Sei
Replies: 1
Views: 1773

Re: Another Mad South African project - V12 Alfa Sei

The V12 would have been a better fit in a JZA80 Supra.............. :D
by Duk
Tue Nov 29, 2016 2:12 am
Forum: Gearbox, Clutch and Driveshaft
Topic: transaxle upgrade's
Replies: 53
Views: 17455

Re: transaxle upgrade's

From Kevin's thread on the 75 IMSA car viewtopic.php?f=21&t=4115, a rather non-aluminium bearing plate in the middle of the gearbox.
by Duk
Wed Nov 23, 2016 9:19 pm
Forum: Gearbox, Clutch and Driveshaft
Topic: transaxle upgrade's
Replies: 53
Views: 17455

Re: transaxle upgrade's

An alloy steel bearing plate??? Or find out if vacuum infusing a laminated a carbon fiber component that is 30+mm thick is doable and then machine the CF to suit? Maybe would want bronze inserts for the shift rods? You could also look at making the the areas around the 2 bearings thicker on the inpu...
by Duk
Fri Nov 18, 2016 11:49 pm
Forum: Gearbox, Clutch and Driveshaft
Topic: transaxle upgrade's
Replies: 53
Views: 17455

Re: transaxle upgrade's

So either make an alloy steel 1 of go completely mad and actually create a carbon fiber bearing plate????
If it was made solid like your custon plate, it wouldn't be very light. But it would resist deflection like (basically) nothing else!
How thick is the central plate?
by Duk
Thu Nov 17, 2016 4:18 pm
Forum: Gearbox, Clutch and Driveshaft
Topic: transaxle upgrade's
Replies: 53
Views: 17455

Re: transaxle upgrade's

Measure results of the billet aluminium plate are a 37.5% increase in bent stifness.About 0.045 movement That's not bad. I aspected a little more because of the better material and the not weight saved part. An excellent improvement! Would it be worth while to make a new bearing retaining plate fro...
by Duk
Fri Nov 11, 2016 9:10 pm
Forum: Suspension, Steering, Wheels, Tires
Topic: Front - Rear track width and transition while cornering..?
Replies: 20
Views: 9118

Re: Front - Rear track width and transition while cornering.

One question; bump steer can be corrected with additional positive caster? Idea is to reduce camber from -3,0 to -2,0 and add more caster. My long shank upper ball joints are 20mm longer than those from factory... Heres photo of some additional custom work :) Unfortunately not. I thought that becua...
by Duk
Tue Nov 08, 2016 11:33 pm
Forum: MegaSquirt Fuel Injection
Topic: Tach circuit
Replies: 1
Views: 3051

Re: Tach circuit

I've not tested the idea, but there are cheap little PCB mounted relays that have the required drive circuitry to be triggered by a 5 volt signal. For only a few dollars and a compact surface mount design, I'd give this a go.
Look for 'Arduino Relay' on ePay.
by Duk
Sun Nov 06, 2016 5:06 pm
Forum: Gearbox, Clutch and Driveshaft
Topic: transaxle upgrade's
Replies: 53
Views: 17455

Re: transaxle upgrade's

Looking at a workshop diagram of the gearbox, the thrust loads from the pinion gear are fed into the case via the centre plate. It doesn't matter where the thrust bearing is on the output shaft, so long as the shaft, bearing mounting point and the case in general are suitably rigid. Your idea about ...
by Duk
Thu Nov 03, 2016 9:36 pm
Forum: Gearbox, Clutch and Driveshaft
Topic: transaxle upgrade's
Replies: 53
Views: 17455

Re: transaxle upgrade's

Awesome information! This is the sort of stuff, like MD's clutch housing brace, that helps the Alfa community progress and stay in 1 piece. It's probably a bit hard to get across to people in other parts of the world, but here in Aus, there weren't that many Alfa's sold. So If I smash my 1990 75 Pot...