Hi guys, what boost do you run for a health 400bhp on a cossie yb? I'm trying to figure out weither I have selected a suitable turbo for my project but cannot figure out the pressure ratio needed for the compressor map.

I know I need 40-42Lbs of flow but @ what pressure is the thing I cannot figure out....I think this might be unique to each engine...as a few psi on one engine is more of a gain that on another etc....

I have a ported head (inlet side mainly) I think theyre 2-3mm over std when I measured them a while back if that makes a difference to boost required (I read so many times that boost is a measure of restriction not flow )

Cheers
Dan

 

anyone?

 

aint got a clue mate only way would be to get it live map

 

I dissagree.....If the only way to know was to live map then turbo selection would be trial and error....with a live map inbetween each swap. Or a selection based on other peoples trial I suppose.

I need to know the boost required @ 40-42Lbs of airflow for a YB....someone must know So that I can figure out where abouts on the compressor map I am for the turbo I think is right for me.

I'm looking at this turbo to deliver the power....


Is this going to be capable of delivering the air I need to for 400-420bhp?

Ohh I forgot to say it'll be externally gated with a tial gate

Cheers
Dan

 

http://boardroom.wscc.co.uk/cgi-bin/...;t=48906;st=15

Interesting discussion on compressor maps.

CNG1 is running a GT28 aswell.

Page 6 has some info on reading compressor maps

 

Just over 1.8BAR or 28psi should see you 400Hp

 

Dan what are you doing just getting advice from people on Internet forums and the building the engine from the parts you feel are most going to suit what you want?

I used to think like this and still do in some ways but its best to get a good tuner on your side and ask more buy less, i have wasted a bit of money in the past buying things i didn’t need but at least i stopped before i spent any major money

I would seriously call up someone and get some pro help on this build and not listen to people who know fuck all "like my self lol"

please keep us posted tho as i am interested in what you are trying to achieve

 

Well I have had engines in the past and bolted turbos to them which to be fair work well but are within the limits and arent particularly responsive or strong.

I have been told by a few tuners that you need to decide turbo spec and then spec an engine to suit..... I am planning on a rebuild/spec change so that canvas is blank (obviously if I can use existing parts as much as possible then it'd keep costs down but that'd be a bonus...if it needs changing to suit a responsive turbo setup I'll change any component necessary).

I am trying to determine if a roller bearing turbo of this size is a viable option for a very responsive setup @ 400bhp....The whole t34 and std engine just doesnt float my boat and IMO would be good enough but I'm not going for big power I just want to make full use of a sensible (bank manager still breathing) 400bhp from my engine. Final spec etc... would all be discussed with my tuner, I just like to know & understand the theory myself before I approacha tuner with an idea to discuss.

I think that 1.8bar is not 1.8 on the graph like you show mate...I make 1.8bar equal to 2.8pr (or26.46psi)...


so thit turbo is very close to its limits at that...possibly get it within range with a diff exhaust housing but I'm not sure.

Dan