Cams for turbo engine question

[Andyman]

What would the effect be of having a exhaust cam with less duration and lift than its mating inlet cam? - turbo application


Im basically building a 2 litre turbo engine (non Renault) - The donor engine has high lift cams as standard. The 1.8 cams from the same model are exactly the same fit but have less lift and duration inlet and exhaust.

I know the exhaust cam change would help spool the turbo up quicker but not sure if i should stick with the high lift inlet cam or change to the 1.8 lower lift and duration.

 

[Chip-mk1]

You havent given enough info for anyone to providing you with must useful info TBH mate.

What engines?
What are the standard cam profiles you mention like?
What turbo?
What is the application?

Personally I like hot cams with turbos but it tends to end up quite revvy of course, so if its low down grunt you want its not the way to go.

 

[Andyman]

Its a Zetec turbo Chip, running T34, .45 housing.

Just wondering if i should replace the stock 136ps cams or mix and match with 105/115ps ones.

 

[Chip-mk1]

Those engines are so mildly cammed anyway that I wouldnt even consider going down the range mate.

You say .45 housing, do you mean .48 (ie T3 saph cossie?)
They are 0.63 as standard on the escort cosworth.

What car is it going in?

Ive mapped a couple of zetec turbos and they are actually an engine that really likes being turbo even though they werent from the factory, especially as (due to the oil pump in the zetec's case) they arent an engien you can easily make big power out of N/A as you are limited on revs (like an F4r, all be it thats cause of rockers etc not the oil pump)

 

[Andyman]

Sorry yeah its a .48 housing although i thought that was a T34. Looks like a T34 compressor housing anyway as the actuator bracket is part of the housing unlike the T3.

I bought the OFAB chip from the lad with the blue mk2 Fiesta. He was running a Ian Howell exhaust cam and getting some awesome quarter mile times. My spec is just about the same bar the cams hence the topic lol

 

[Chip-mk1]

TBH I wouldnt be binning that and just buying an OFAM or Omex or similar, I really am not a fan of the standard RS turbo management.

 

[Andyman]

Yeah its not the best but its just purely to get me up and running and to keep the project costs down.

 

[Chip-mk1]

Make sure you run it with a wide band and det cans or it could be the most expensive cheap way of doing things youll ever find.