Project MACH 1 - 2.5 Litre V.V.T. STi
the smart money on a skyline goes for 2 parallel turbos.
sequential is fraught with problems, which can be overcome with development, but not what you want to be doing with the rest of your project IMHO.
I will start the CAD today...
Paul
sequential is fraught with problems, which can be overcome with development, but not what you want to be doing with the rest of your project IMHO.
I will start the CAD today...
Paul
Rocket Rons runs very well on one turbo but then again the Sumo power one runs even better HP with two. Probably more real world driveabillity with two smaller ones. 
Paul, not sure what you mean
Conrad

Paul, not sure what you mean

Conrad
Rocket Rons runs very well on one turbo but then again the Sumo power one runs even better HP with two.

However, Keith Cowie is wedging in an HKS T51R SPL into his, going from 2 quite smallish turbo's (2830's?) to a frigging monster single....
Sorry, misinterpreted the
not the CAD part. 
Conrad
They should be here next week if you want to wait until I can send a pair of them to you. They will be mated together via throttle linkage and fuel rail, hopefully ala the tumbler housing spacing.
Cheers
not what you want to be doing with your project IMHO

Conrad
They should be here next week if you want to wait until I can send a pair of them to you. They will be mated together via throttle linkage and fuel rail, hopefully ala the tumbler housing spacing.
Cheers
Scooby Regular
Joined: Nov 2001
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From: Leeds - It was 562.4bhp@28psi on Optimax, How much closer to 600 with race fuel and a bigger turbo?
Eh... are you calling the vvt crap or the pectel??
If its the pectel, I would read up on the spec of an ecu like the T10, the one pat is using on the 33b, also the fact that you can have the software customised..
Have a look at how many knock sensor inputs, Digital Inputs, Hall effect etc.. and see if you can match it.
Also ask bob to ask Dave Wild what he thinks to pectel.
http://www.pectel.co.uk/assets/t10s.pdf
David
If its the pectel, I would read up on the spec of an ecu like the T10, the one pat is using on the 33b, also the fact that you can have the software customised..
Have a look at how many knock sensor inputs, Digital Inputs, Hall effect etc.. and see if you can match it.
Also ask bob to ask Dave Wild what he thinks to pectel.

http://www.pectel.co.uk/assets/t10s.pdf
David
David: Not sure if the post above is directed at me but if it is I have no idea where you are coming from.
Read back in the thread and you will see Conrad thought that ProDrive were using Pectel and had problems with the software to control the VVT which is not the case.
I think Pectel make very good kit although it is more expensive than some other ECUs but then it has far more features than most Subaru owners would ever use.
VVT. I already said I understood it was worth 30bhp and for Conrad to junk it was a retrograde step.
Turnips and potatoes. Well what is good for a rally car doing short stages on poor surfaces with a 32mm restrictor and what is required for a road car is like comparing oranges with lemons.
No idea why Bob needs to talk to David Wilde about Pectel. He has his own knowledge of their products so I do not know what all that is about unless I have wrongly assumed you were addressing me.
Read back in the thread and you will see Conrad thought that ProDrive were using Pectel and had problems with the software to control the VVT which is not the case.
I think Pectel make very good kit although it is more expensive than some other ECUs but then it has far more features than most Subaru owners would ever use.
VVT. I already said I understood it was worth 30bhp and for Conrad to junk it was a retrograde step.
Turnips and potatoes. Well what is good for a rally car doing short stages on poor surfaces with a 32mm restrictor and what is required for a road car is like comparing oranges with lemons.
No idea why Bob needs to talk to David Wilde about Pectel. He has his own knowledge of their products so I do not know what all that is about unless I have wrongly assumed you were addressing me.
Harvey,
vvt is not worth 30 peak bhp, it might be worth something lower down, but then that is comparing cam for cam. In conrads situation he wants to go for very wild cams and that means having custom vvt allowable cams made up. (I don't see why he can't reprofile his existing cams and have the best of both worlds).
If he needs new cams, then the uptop gains he will get from those will far outweigh the low down 30bhp gain from being able to alter the timing.
I am not fussed about low down performance except with regard to making the car too good.
My car made over 200lbft off boost prior to the turbo coming in, and though the engine dyno brings boost in earlier than it would have been on the road, at every point on the graph (even accounting for early spool up) the 2.5 with a big turbo was way way ahead of the standard 2.2 sti with a vf23 mapped by bob(in my case).
it jumped from 230lbft at 3500 to 500lbft at 3700 when asked to, so I am not entreily sure that with conrads even wilder spec (I assume) the loss of 30bhp is not going to be a real problem.
vvt is not worth 30 peak bhp, it might be worth something lower down, but then that is comparing cam for cam. In conrads situation he wants to go for very wild cams and that means having custom vvt allowable cams made up. (I don't see why he can't reprofile his existing cams and have the best of both worlds).
If he needs new cams, then the uptop gains he will get from those will far outweigh the low down 30bhp gain from being able to alter the timing.
I am not fussed about low down performance except with regard to making the car too good.
My car made over 200lbft off boost prior to the turbo coming in, and though the engine dyno brings boost in earlier than it would have been on the road, at every point on the graph (even accounting for early spool up) the 2.5 with a big turbo was way way ahead of the standard 2.2 sti with a vf23 mapped by bob(in my case).
it jumped from 230lbft at 3500 to 500lbft at 3700 when asked to, so I am not entreily sure that with conrads even wilder spec (I assume) the loss of 30bhp is not going to be a real problem.
The VVT will help promote earlier spool up of the turbo, I dont believe it gives any more power just moves the power windown around, for my application when I'll be using the turbo hard I'll be setting off alot higher up the rev range. I am hoping that the 2.5 will have sufficient driveabillty off boost to behave like a normal(ish) car day to day.
Went to the Autosport show yesterday and gained several new ideas, spec is now going to change quite dramatically after spending time on the Cosworth stand
As for Pectel, I said this was used by the Prodrive Group N cars with locked VVT. Gems Utilises the VVT on the WRC cars.
I'm going to use DTA ECU, it has all the features I need, Launch Control, 8 injector control, Antilag etc etc (including cam control(for the future)) and its £900 and comes with free software.
Conrad
[Edited by RSVR Racer - 1/9/2004 1:11:38 PM]
Went to the Autosport show yesterday and gained several new ideas, spec is now going to change quite dramatically after spending time on the Cosworth stand

As for Pectel, I said this was used by the Prodrive Group N cars with locked VVT. Gems Utilises the VVT on the WRC cars.
I'm going to use DTA ECU, it has all the features I need, Launch Control, 8 injector control, Antilag etc etc (including cam control(for the future)) and its £900 and comes with free software.
Conrad
[Edited by RSVR Racer - 1/9/2004 1:11:38 PM]
Cam timing can easily add 30hp. It of course depends where they are set in the first place!
Where it really adds power is that you can run higher duration cams that you can normally get away with.
Paul
Where it really adds power is that you can run higher duration cams that you can normally get away with.
Paul
Adam : I am told by three guys, separately that the the VVT is worth 30 bhp and as they make their money out of this sort of thing and are usually correct, I accept what they say. They are working on these engines on a daily basis and their livelihood depends on it.
Conrad : The ECU Pro Drive were using to control the VVT was not Pectel.
David : Hope you have a good blow out.
Conrad : The ECU Pro Drive were using to control the VVT was not Pectel.
David : Hope you have a good blow out.
Cam timing gain is directly related to the cams its applied to, there are good gains to be had but not above 6800, on a rally car thats not the point though as they are pretty pants by the time they get there, so the cam timing is important for rally, which is why the non vvt cars always ran abnormal timing compared to road, I recall Anders engine running "prodrive" cam timing when I mapped it at Dave Wilds, made great torque ... 371 ft lbs at 3000 rpm from a VF23, all over by 5500 though and barely made 320 bhp, we thought it was good at the time though, torque was made at 1,4 bar iirc.
My own experiments have proved interesting, my STi9 responds alot differently to the earlier STi's with VVT but it does have more aggressive cams, VE does seem to be an improvement.
bob
My own experiments have proved interesting, my STi9 responds alot differently to the earlier STi's with VVT but it does have more aggressive cams, VE does seem to be an improvement.
bob
The ECU Pro Drive were using to control the VVT was not Pectel.
Nor was it Gems.
"Harvey thats what I said??
Group N Cars - Pectel - Locked VVT ie ECU NOT controlling it"
Hope that is cleared up now. NOT Pectel and because of the control problems, software work is being done to overcome the issues and it may well be that they return to VVT in the near future.
Anyway as Bob is also pointing out there are big differences between rally preferences and performance and what is needed in a road car.
[Edited by harvey - 1/10/2004 8:34:21 AM]
[Edited by harvey - 1/10/2004 8:44:58 AM]
Nor was it Gems.
"Harvey thats what I said??
Group N Cars - Pectel - Locked VVT ie ECU NOT controlling it"
Hope that is cleared up now. NOT Pectel and because of the control problems, software work is being done to overcome the issues and it may well be that they return to VVT in the near future.
Anyway as Bob is also pointing out there are big differences between rally preferences and performance and what is needed in a road car.
[Edited by harvey - 1/10/2004 8:34:21 AM]
[Edited by harvey - 1/10/2004 8:44:58 AM]
Harvey,
am not arguing with your experts, we both know I am no engineer, but bob has agreed with what i said in that there are no gains to be had over 6900rpm. I assume that yours annd most other peoples peak power is at that rpm or possibly higher, suggesting that the 30bhp gain comes lower down the rpm range and hence does not increase peak power.
am not trying to be antagnistic, just passing on what I believed to be correct. Am open to correction as ever.
am not arguing with your experts, we both know I am no engineer, but bob has agreed with what i said in that there are no gains to be had over 6900rpm. I assume that yours annd most other peoples peak power is at that rpm or possibly higher, suggesting that the 30bhp gain comes lower down the rpm range and hence does not increase peak power.
am not trying to be antagnistic, just passing on what I believed to be correct. Am open to correction as ever.
Adam : I accept the VVT will make no difference at high revs but it will make a big difference getting there. BTW there are a lot of cars making peak power lower down. It obviously depends on the mods and while rally engines are not particularly relevant here most of them change up between 5500 and 6000 rpm.
Very nice but there doesn't seem to be any point in forming a queue as, sadly, it will be "later in the year" before this is available. APS appear to have a policy of teasing everyone and then waiting for a response
thats what i thought andy. they go to all that trouble of doing that and then dont reverse it. Although it does look as though its easily reversible in the centre section, i think



