So uptil this morning i hadn't pressed the throttle all the way down on the Sei. This was because it was underfueling on full boost blah blah, is unimportant.

Anyways, the fuelling has been fiddled with today and now i can happily put my foot right down without fear. However, i notice now i can do it that the car that the boost comes in real strong and quick and reaches 11psi on my guage at about 2.5k revs. But at about 3.5k revs boost starts to die off again, reading only (approx) 5psi from 4.5k upwards.

My assumption on this is that the standard exhaust is holding it back at full chat, this a reasonable assumption?? This is not something i ever had happen in the old tub, even when its was seriously over-boosting it held its boost right through the range. The main difference as i can see between the 2 cars is that the cinq tub had a sports mid section and janspeed backbox although this was all standard bore as well.

Opinions please.

Certainly not unreasonable, however at least two other things to consider -
Is the map take off from the same place on both cars?
could the wastegate be leaking up at higher rpm?

Did Jamie get around to fitting the EBC?

I found when i had the new exhaust that it spooled up a lot quicker and reved a lot freer but I still had the boost tailing off caused by the wastegate creeping open higher up the rev range, the greddy solved this though.

If it were my car I'd go for a nice free flow exhaust and a EBC then lots of tweaking

I would actually say though as yours is a low boost that it is overboosting at lower revs if it is hitting 11psi that is 0.75 bar which is high boost teratory and that would concern me more

i thought that Sei was a hiboost?

arc said:

i thought that Sei was a hiboost?

Click to expand...

not at 0.5psi it isn't

but you might be right in which case that is one hell of a boost leak or something has collapsed in the exhaust

Edit or something in teh intake in collapsing under vac

Never did get an EBC for it

The boost always seemed to ease off up the revs which I always though was down to the exhaust and lack of EBC as well

Wouldn't of thought that anything is collapsing under boost although the filter could do with swapping for a CDA and tucked somewhere out of the heatsoak form the engine

It's as sugested wastegate creep at higher RPM, all the hi-boosts do it as standard, as there is no form of boost control other than wastegate, unlike most manufacturer built turbo cars which do have a form of boost control.

The exhaust is massivley restrictive as its built for a 54bhp N/A engine, not a 100+bhp turbo engine even if its an aftermarket one.

There is really 3 things you need to do.

New custom made exhaust
Electronic boost controller
Air filter moved to area of cold air flow out of engine bay, inside front wing between wing and arch liner is good. Though on the MPi Seicento the carbon can is situated there, don't know about SPi.

Get it on rolling road to ensure all is still well fuelling wise after doing this.

OK you all have just said the top bits of my to do pile so all is good. I will prob not really be doing anything to it until after xmas. I just checked the fuel pressures y'day and the 2nd inj was well down, primary was fine, 1.4bar. So just tweaked the fpr up a bit and she drives nice again it really needs to go on the RR but I'm just taking it steady until january and then i'll start tweaking properly. Its not really being driven much, working from home alot at the mo.

Rolling Road is just a matter of deciding which one to go to, i'm down to 2 which i'm gonna go check out soon. Daytuner in shipley, which has been recommended by my local motor factor blokey and Kershaws just outta York which is an Alfa Specialist and tuning garage.

I'm prob taking it to same place as Martins exhaust was done (Zorstec) for new custom pipes, also in shipley.

And i got my eye on ebay for boost controllers. Not really sure which one to go for but theres loads of them about for reasonable money

It depends on how sofisticated you want the EBC really. The preferable EBC's are ones where you can set the gain dependant on RPM (sometimes even road speed).

These make the car much more drivable as you can smooth out the power and torque curves by adjusting the gain and solenoid duty cycles accross the rev range, of course these are more expensive and take it from me a real pain in the arse to install, (I am still wiring bits of mine up even now)

There are also ones that will give you safety features (mine will cut boost if it goes lean for example) you might want to think about that if you are sticking with the VAD/MF2 setup

In the end it is down to how much you want to pay

looking at this

i'd look at this;

http://cgi.ebay.co.uk/GReddy-PRofec...14&_trkparms=72:1299|66:2|65:12|39:1|240:1318

can pick up an AVC-R for £175 or so second hand, expensive but has some very good features

arc said:

i'd look at this;

http://cgi.ebay.co.uk/GReddy-PRofec-B-Spec-II-electronic-boost-controller_W0QQitemZ170283926525QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item170283926525&_trksid=p3286.c0.m14&_trkparms=72%3A1299%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

Click to expand...

Watching

I like these because I think the gauge size fitting makes it so much easier to fit it, plus does away with boost gauge.

http://www.aempower.com/ViewCategory.aspx?CategoryID=68

https://www.funkypower.co.uk/catalo...l1=&level2=&level3=&id_product=4185&man=MUGEN

They are quite groovy aaron, i've just bought a Blitz Dual SBC DSBC Spec-R off ebay.


Just looking at dumpvalves/blow-off valves. I done a little reading on them and as far as i can tell the difference is this - a BOV opens and recirculates the pressurised air back to the inlet of the turbo which allows the turbo to keep spinning by equalising the pressure on both sides (not sure if this would 'tisch'?). This is obviously gonna decrease spool up time so is good.
The BOV's can also recirculated to atmosphere (defo go 'tisch') but as far as i can tell then its just doing the job of a Dumpvalve

Dampvalves (we all know 'tisch' lol) 'dump' to atmosphere but because pressure on the backside of the turbo is at a higher pressure than on the front side the compressed air acts as a brake on the turbo (slowing it down), so better than not having anything but not as good as a re-circulating BOV.

That make sense? just wanna get what each is sorted in my head

Took the dump valve off today, my suspicions were correct its faulty, car holds boost fine without it there.. So in the market for new one, preferrably adjustable

blu73 said:

Took the dump valve off today, my suspicions were correct its faulty, car holds boost fine without it there.. So in the market for new one, preferrably adjustable

Click to expand...

Is that the one I left in the car? if so I told you it's not right

nope different one