peteh

iTrader: (3)

In a well ported cylinder head, i know alot of people now run a say BD14 inlet and standard exhaust, but what would you loose on a BD16 exhaust with a 16 inlet of course?

ta

peteh

iTrader: (3)

all i can think of, is getting the gases out quicker

Lloyd

the cams need to match the spec of the engine,and what you want from it power wise.ie. when its delivered and how,

peteh

iTrader: (3)

450bhp tops, quick road car and strip

also was thinking 6.8 comp as i know of a once quick engine which made 350bhp on 17psi, so thought this was a good choice as it's not putting loads a boost through and hence make it reliable then just up the boost, maybe?

BigErn

Lawnsy on here is running comp in the high sixes. He reckons its poo off boost!

peteh

iTrader: (3)

strange as the one i went in, felt awesome felt no laggy then my stage one, this was a T34.63.

cossiemanden

There is a lot of but`ts here.
U can adjust your way out of a lot of the problems with mismatch camwise, but u should defo choose the right cams the 1. time.
And how to do this is to choose what karacteristics your engine should have.
Track/street(buttom and midrange power) or drag(top end power).
The karacteristics off the head porting does also count is this.
If i were u i would choose an bd-14 inlet(set a few degrees advance) and std exhaust cam, mild portet head and arround 7,5 komp.

bud-weis

i have similar cams ( i think mine are equivalent to BD16+ )

in all honesty they aren't too bad at all, the spec for my engine isn't perfect but it's ok. with the ported head it makes 420bhp at 1.7bar on the T38 which isn't too bad i don't think. If it was set to hold 2bar i'd expect it to be 450bhp.

marco polo

iTrader: (1)

why do you want bd 16's with a t34 turbo absolute waste of time

these cam will be only coming in when your turbos runnig out off puff

marco

Butch.

iTrader: (1)

waste of time

cossie4i+

iTrader: (15)

What do you know ?

You own a BMW

Steve.

Butch.

iTrader: (1)

Yeah might do but i have worked on more rs's than you will ever have

puddy

BD16's,6.8:1,T4 =

puddy

Stavros

BD16s are hardly any more duration than BD14s, but still, OTT for the power you mention.

Unless your limited on the boost you can safely run, keep the cams as mild as you can.

BD15s look good, shorter duration than BD14s but loads of lift.

RWD_cossie_wil

iTrader: (9)

STD exhaust cam, BD 14 Inlet cam on a MILDLY ported head, 25/26mm, 7.4:1 comp with pocketed pistons for valve cut-outs, T38 From Ian@Racetek , std inlet plenum, and a damn good mapper, IMHO STU@MSD, and you will have a weapon of a car .....

Don't over-spec your engine, just upgrade what you need to or you will end up with a horrible laggy expensive peice of shit thats horrid to drive due to the spec being massivly mis-matched

Didn't you sell an engine that made 570BHP but only just over 400 Lbs/Ft? - the graph on that told the whole story of a too-big turbo and too-big cams - for a quick road car/ occasional trackday toy, you need TORQUE and drivability, whats the point in loosing 80Lbs/ft of midrange torque over a couple of 1000 RPM just to gain 20BHP at the limiter?

bud-weis

it may not be ideal but it's a far cry from being 'a bag of shit'

424bhp/388lbft isn't that shabby, and that's without a huge spike of boost! and it drives pretty well too.

lets not just presume it's gonna be shit because you read on here it is!

RWD_cossie_wil

iTrader: (9)

I never said that your car is a bag of shit , and I recon if you dropped down to some milder cams you would see a large improvement in the midrange , just look at the power and torque that Ad's car makes, and neils car, both on much milder cams ..... A BD14 cam's powerband is 2000-7000 RPM, A BD16 is 3500 to 8500, be honest, how often do you drive at 8500 RPM? , and to be honest why run those cams with a T38 turbo? all you are doing is robbing yourself of midrange....., especially as a BD14 will quite happily do 500BHP+
Just IMHO of course......

Deleted by Request

...std exhaust cam all the way

bud-weis

It wasn't directly aimed at you mate..just the general consensus seemed to be that it'd be shit, when in truth it's not.

i never actually specced the engine myself, if i had i think the only thing i'd change is the T38 for T4.

it wouldn't really make a great deal of difference changing cams...the T38 doesn't spool up quick enough to make advantage of a milder cam IMO anyway. Once it's on boost the power doesn't drop off at all....as shown on the rollers last week, the car was still making power when he lifted at 6500rpm, i normally rev it to 7k

I do agree with T34 cars that you shouldn't use different cams, in fact i much prefer them on standard cams...only downside being you have to wring the neck of the turbo to get anywhere close to 400bhp, which can get expensive.

peteh

iTrader: (3)

what turbo?

the engine isn't built yet, just i brought the BD16's as i was thinking about going the same spec as puddy as ive been the same spec'd engine car but it was a T34.

what's the thing about standard exhaust cam? does it hold the boost in or something?

rapidcossie

Bud...why didnt the operator run it to the rev limiter if the power was still increasing?

bud-weis

tbh mate i dunno....i can only assume he thought it was a T34 and 6500rpm was enough

unfortunately by the time we'd discussed the rev limit, and the time it took to get enough weight on the back to stop it spinning..the ACT's were too high to make any extra power anyhow....although it wouldn't have made lots more i don't think, it wasn't rising at that high a rate.

rapidcossie

I thought operators kept going until the power stopped increasing?

Why would you only rev a cossie to 6500 RPM?

had you told him to cap the revs?

bud-weis

nope. i never told him to do anything.

if it were me i'd keep going until it hit the limiter or the power dropped off.

rapidcossie

makes sense to me mate

Stavros

err, thats the point of milder duration cams on turbo cars, THATS the main thing that gets a turbo spooling soon or not, so any turbo on earth will find a milder cam an advantage to spoolup.

bud-weis

yeah..but you can't perform miracles just by running a milder cam.

there's no way on earth my T38 could be made to spool like a T34.48 or similar.

i'm not saying that my cams have any advantage whatsoever, just that they don't really hinder MY spec too much, if they did i'd change them...simple as that.

Stavros

you ever tested that?

cams perform a lot more miracles than people seem to think

then again 265deg is still pretty mild in the grand scheme of things anyhow.

rapidcossie

Bud...

yor T38 CAN be made to spin like a 34.

My T4 spins like a 38 so no reason why yours can be the same.

When doing my cam timing my power graph was constantly overlaid against a 38 equiped car and mines is every bit a good at the bottom end then it just mauls it after 4k

Cam timing has ALOT to do with this.

get your car timed properly on a RR that can re create, consistantly back to back runs and see how you get on.

this degree of cam timing cant be mappe don the road.

bud-weis

Stavros
No but i'd like to..i would imagine the threshold could be improved which would certainly make it a bit nicer to drive.

i bet half the people who think they are THAT bad wouldn't even notice them if they drove my car

bud-weis

rapidcossie

unfortunately there is nowhere in my area i know well enough, to trust them to do it properly.

i agree that using a RR to keep making constant changes is a big advantage too...NMS have mentioned having a set installed, not sure if it will be seriously considered or not.

i'd love to try it, but i'm not that arsed at the moment...the amount of times i actually get to give the car proper grief is limited anyhow...the amount of saxo/pugs around here mean i don't need to go over 4k very often

rapidcossie

I can remember watching mine getting done..

It was pretty amazing to watch the power increasing with out actually doing very much apart from moving the pulleys.

We couldnt actually believe it when we over laid the graph with the T38 car as we didnt expect it to have that much of an effect on things.