Cyclone valve opening RPM....

[kaptainballistik]

Hi all

Now these pesky cyclone valves...... Being a Production Rallycar and having a restrictor, I should have full boost by 3500rpm

Which I dont!

I have been informed the valves should open at 4250 rpm (Which seems high ..But MEH...) I was talking to Meek and they suggested they should open at 2800.....

I reset the autronic to 4000rpm opening and the car went better.... I need to more testing but when should they open? ( Ive got a boost cut setting issue so changing stuff is getting problematic)

So who is right or should I just punt them and fit my EVO 0 intake....

 

[to4garret]

4200rpm is stock

 

[blackvr]

I did a heap of tuning on our VR4 gravel rally car last year. I actually ended up using an ASpec inlet manifold. It made less torque between 1500-2500rpm compared to the cyclone manifold, but considerably more between 3200-5000 rpm. The power drops off after 5000rpm due o the restrictor.

Regardless, with a big 16G style turbo, we were making 23psi at around 3200rpm on both manifolds. In actual fact, even at 2500rpm, it was making 16psi . This engine on a diet of E85 fuel is an absolute torque monster beyond belief !! It has roughly 35% more torque at 3000rpm than a PULP tune ( using 900cc injectors and the stock ecu that I have rechipped). My driver was a bit intimidated initially ie shat himself by the extra power. At last years ARC round in Adelaide, we were running the equivalent of 7th outright times if we were in the ARC category. Now if we can get the old girl to handle as well as the late model machinery at high speed .... It does seem to hold its own in the rougher forest stages though ...

Mike

 

[VR-4Squid]

Evo 0 manifolds also have the same duel runner/butterfly setup - the only difference is the writing on the plenum.

 

[to4garret]

yea, isnt it "Turbo Intercooler" vs "Cyclone" or something

edit: Mine says "ECI Multi, Turbo Intercooler"

 

[MDK87]

What's the "O-Restrictor" Mike?

 

[doommachine]

Hasn't testing been done on these though, and the long runners on the cyclone are the same as the A-spec?

Sorry, didn't answer the question asked. On the old US GVR4 forums a lot of testing was done, and with later opening times better low end was had, and although boost started lower, it wasn't as strong as quickly. So.. I think with what blackvr is saying you'll be better off going with an A-spec manifold.

If you like.. I'll trade you

 

[rob323]

KB, irrespective of when the butterflies open, this has nothing to do with your late boosting problem. Just a thought, is the cam timing correct?

 

[blackvr]

What's the "O-Restrictor" Mike?

Typo... "due to the restrictor". The PRC gravel rally regs require us to put a 34mm diameter restrictor in front of the turbo. So at around 5000rpm , the airflow is severely restricted and power drops off "BIG" time. You will generally find restrictor motors built with higher compression,smallish turbines for early spool and largish compressors to pump that air. Consequently, with the right fuel and boost, they respond with awesome tractor like torque down low and low revving early shifting. With a close ratio dogbox, they are pretty quick!

 

[rob323]

Next time you go to a rally Mo (woops first time you go to a rally), have a listen to the cars, you will easily tell who is running a restrictor and who isn't. Subaru's sound like they change gears at about 4000 rpm.

 

[MDK87]

That is.....when you take me!! haha
Ahh ok, gotchya Mike.
Thanks for clearing that up.

 

[VR-4Squid]

yea, isnt it "Turbo Intercooler" vs "Cyclone" or something

edit: Mine says "ECI Multi, Turbo Intercooler"

and mine says: CYCLONE, Turbo Intercooler.

 

[turbovr4]

i just found out that my vacuum actuator has a leak so my runners are open all the time ,so all eight runners are used. didn't really notice when it first broke can still sit in 5th up the maleny range at 80km.how much torque difference are people talking about?

 

[rob323]

More than enough to make it worthwhile to fix it.