as title really

borrowing a firends saf at the min but im a bit concerned on the lag, off boost its quite flat and ill have to wait about 20-30 seconds for boost to come in and about 5 secs for it to get off vacumn to go to zero on boost gauge

spec is std engine as far as i know, t34 with .48 ex housing
500 interocoler, exhaust, greens, live map etc, usual stage 3

just wondering if anyone can give me some ideas on what to check for that would cause this lag as it should be at least half as my old cossie was no where near this amount and i was on low comp and a igger ex housing

or could it be how the turbo is built?

 

try changing from 5th gear at 1000rpm, to 1st gear then.


Or perhaps give some more useful information about how or when boost is achieved.

 

i carent give an acurate reading on revs as its on coil pack conversion but rev counter reads funny

and ill tell you what you go from 5th to 1st and tell me what happens yeah,let you destroy your own car

alls im saying is the car is quite flat when off boost and takes ages to get off vacum even in 1st gear hence ive put some times up hwow long it takes to get on boost

 

Jeeeesus.

So you are sitting at 1000rpm in 5th gear and it takes forever to boost.

Or are you sitting at 1000rpm in 1st gear and it takes forever to boost ?

How exactly would any harm come at 1000rpm in any gear ? catch a grip.

Fuck sake use a bit of common sense. Even without a rev counter any dummy could tell if you are sitting at 1000rpm, or 4000rpm.

Without proper details the question is meaningless.

If you are saying you are driving along at say 3000rpm in any gear and put your foot down and it takes forever to build boost, then it would make more sense.

but as you word it, it sounds like you are sitting in 5th gear at 1000rpm, so obviously it would take forever to boost. So no problem there.

If it is as laggy as you say, then blatantly obvious things to check would be for boost pipes leaking or undone. How much boost does it actually make when it does build ? Or dont you have a boost gauge ?

 

Whats it like when its on boost?

 

when it comes on boost its hard on boost

but say your in 2nd gear cruising at 30, but your foot down and it will take around 20 secs or maybe more to actually start comming on boost but as soon as it starts its comes hard on boost

is that better?

 

it depends on your definition of LAG. imo. when you change gear at max rpm,the boost should be there straight away.= no lag
if you change gear at max rpm and then have to wait for boost,that is lag.

 

Still vague, but yes much better.

But you still havent said if its making 1psi, opr 30psi.

Did this just happen, or was work carried out then it happened ?

 

gota ya

ok i wouldnt say its lag, id say turbo spool up

it takes roughly 10-15 secs to start comming on boost so thats from neg vac to 1 pis, then it will come in with a huge bang and hit full boost

i supose what im saying the car quite flat off boost and it takes a while befre the turbo can reach positive psi to give it that bit you need when daily driving like pulling out of junctions etc

as i said its nothing like my old one as i had virtually instant spool up on my turbo and it was a bigger exhaust housing and major low comp aswell

 

So, once again !!!

has this problem just occured, or has some work been carried out and then it occured !!!

 

Mate are you sure its not a low comp engine? even outside the boost threshold the std 2ltr should be plenty to pull you out a junction.

 

Or maybe its a straight diesel ?

 

It could have a boost leak somewhere.

 

as far as i know this is how its always been

no boost leak, as when we gae the car a resto he used some milkalor clamps which just leaked there arses off, we have pressure checked it to 32psi and not a single leak anywhere

when we had the sump off alls we could see is mahle which id say were std pistons

my old car was 7.2-1 comp ratio and i had no where near asmuch turbo spool as this has mine was virtually instant this is kinda flat ntil the turbo actually gets going which im finding strange

 

simple stop driving my car like you stole it

 

Take off the intakehose, turn the turbo by hand and check how easy or not it turns.

 

last time the engine was out the intakehouse was removed off the turbo to be cleaned up,

it turnes freely and no signs of play

I also checked the waste gate penny n this seams to be sealing fine!

 

a mate had a similar problem and it was the exhaust housing, it was cracked everywhere,may be worth checking, only when all the other easier things have been elimminated first.

 

possibly a sticking actuator?

 

cheers dave, will have a look when i get 5 mins, would the turbo not struggle to hold boost though if it was cracked?
because when it does dome on boost its hold psi right up to the limiter?

cheers jay

 

cheers ive got a spare i may git it a try

 

I`ve read somewhere in thepost you had a boostleak, have you checked the turbo bevor or after that.
Cos if you have a boost leak, the turbo can spin with way too much rpms and can cause some damage.

 

Hi TEV i new this was your car that was being talked about do you wont to come out for a spin in my 3dr today and see wot you think as im on a T34 /48 rear 500 cooler.

 

the lag was aas issue before the boot leak, even when the car was set up at msd thy commented it was slightly laggy,

as its the first and only cosworth ive owned i just thought it was normaly but after driving others n rich driving my car its come clear that it is abnormally laggy

 

i think if you had a boost leak it wouldn't get up to full boost at all, and you would hear it i think, same goes for suction side.

try the simple things first m8, check the air filter

 

yer if you could fella, i know your is a higher speck than mine but i will get a kinda idea if my car really is that llaggy

cheers bud

 

Hmm, so if everything is fine, timing, turbo, airfilter not blocked. it could also be the actuator.

 

Iv all so got that pulley for you

 

the boost system has been pressure checked it to 32psi twice and ive had a cone filter and a standard air box 2

 

nice 1 fella im just bout go pic the diff up for rex

 

your tellin me fella kinda clutching at straws

 

if it was the timing it would run and idle like a piece of crap, don't look too deep into it, take a step back and go back to basics first.

 

well i'm pretty sure if it was checked over by MSD, them they would of checked everything that they can think off to sort the lag out.

they may have not checked the ex. housing though.

 

when u say ex housing, inlet or manifold?

 

Well, could be a lot that cause this. To be sure, run it without boost control, but be carfull and keep an eye at the boost gauge!

 

the exhaust housing on the back of the turbo.

mates was cracked everywhere due to the heat etc...

you will be getting boost but losing it though the cracks in the housing,causing lag,until it boosts harder.

whats it like when you take your foot off the revs mid boost...does it take a bit of time to boost up again?

 

yes it could....be if been checked over by MSD, then they would have checked the 'normal' symptoms of boost loss etc....

best to call them and ask what they did check.

 

not saying your a lier m8 lol, but if the turbo housing was split, when you start the car cold it would be quiet, and get louder as the car heat up and the splits opened.

i'd go for either the actuator sticking or a build up of carbon on the butterfly in the throttle body.

 

thats excatly what must happen, but probably not enough to hear it lol.

i'm not saying its 100% that, its something to check as a last resort as he may of checked everything else.

i have seen the turbo ex. off my mates car and it was fooked!

 

msd as said above check evrything as ever their usual faultless service, n it came back with a clean bill of health, but was suggested the waste gate penny may not be sealing correctly!!!

A cracked exhaust housing may be a good call as i know colly sufferd with this only the other week on martoons rollers, so it may be may next port of call

mid rang boot when you let off then power down again it seams ok al be it may be slightly laggy,

higher up the rev range when hard on boost its fine and when you change gear it spools up hard again