Boost problems

Hi all

I have had my 1298cc turbo on and off the dyno a lot lately despite blowing a head gasket we were able to get some pretty good figures 100.2 Bhp at the wheels on 6.5psi measured at the manifold

Problem with this is the more i tensioned the bar on the actuator to try to increase boost i was getting no more boost.
So i measured boost at the compressor housing on the turbo and got a reading of 20psi. I then checked this at the plenum and also got 20 psi.

I have had the overboost valve in the back of the plenum blocked so it cant leak and a new seal kit put in the carb.

Is it normal to lose this much boost across the carb or do i have a leak somewhere i haven't thought of

Cheers

hmmm , tension in the actuator bar wont really affect boost that much but im unsure of why you are getting such a boost drop :S. The boost drop is normal of about 1-2psi.

set the actuator bar to have about half the hole of tension and use a manual bleed valve of electronic boost controller for boost increase. Have your boost guage and actuator readings from the manifold so its actual boost that the engine see's.

i did have a bleed valve coming form the banjo bolt at the top of the manifold as well as the boost gauge but i thought maybe it was bleeding all the air rather than allowing it to register at the gauge

Going to change the way they are connected and see if this helps

Have you sorted your boost probs yet?

Hi

Yes sorted in a way.

Ended up damaging the engine on the dyno and when i pulled everything apart found a large chunk of crap jammed inside the fitting we were using to measure the boost.

This prob means we were pushing a lot more into the engine than realised. Result is three cracked pistons and a 4 thou bend in the crank, all of which is fixable. Im currently waiting on rings for the new pistons and im also getting the flywheel lightened and getting a different grind on the camshaft so should hopefully be all back together in a few weeks

Will keep you posted

wow that's no good , How did the crank bend?

what pistons where you using , there is a pretty good range for 1293 so you should get some pretty good ones. I guess with unknown boost levels its all too easy to give the motor too much timing . Also who you getting to do the cam?

good luck hope it goes well

Hi Ben

Pistons are hypatec (14% silicone) same as the Graham Russell ones
Got the cam done at Waggotts

Not sure how the crank got bent cos it didnt seem like there was much detonation happeningcould have been bent to start with cos i dont think it was checked on first build.

Cheers

engine all back together ?

Hey there

Yes all back together and running very well

Making good power at a lot more sustainable level this time

93bhp at wheels and only 3.5 psi

Have done two sprint events and engine has held up well

Was racing it on the weekend just gone and starting to get some good times until a bit of rain came over

Sadly things got a bit slippery and i ended up nose first into a tyre barrier

Should only be panel damage engine is fine and dont think ive bent any of the drive train

Will have to put some pics up

locht wrote:Hey there
Yes all back together and running very well
Making good power at a lot more sustainable level this time
93bhp at wheels and only 3.5 psi
Have done two sprint events and engine has held up well
Was racing it on the weekend just gone and starting to get some good times until a bit of rain came over
Sadly things got a bit slippery and i ended up nose first into a tyre barrier
Should only be panel damage engine is fine and dont think ive bent any of the drive train
Will have to put some pics up

thats great power , now just up the boost a little

no good about the tire barrier your not having the best luck are you

yeh get some pics pics up for sure

Hey ben

Finally got some pics up these were after i had it out to a panel shop and put on a car straightener

New panels all done now just have to slap some paint on it

Have also invested in a set of Yokohama A048r's so hopefully should have some good grip now

looking good , what happened to the front?

Nice work