TNTRacing - XRCosworth

[pablo]

Wow thats interesting, sitting here looking at the graphs from Gary's dyno day in 2012. At 4000 rpm it's making the same power but at 5000 rpm we now 100 bhp down but then it climbs a lot steeper.

[pablo]

What ever the actual problem is at least now we know where to look/start. Gary, your reply has just given more weight to what we were told about moving the car forward.

Considering we went there with a full list of upgrades we planned and they have said lets look at the boost curve and sort that out first. Actually gives me more confidence to just let them sort it.

[Danny@APT]

sorry but what the fuck!!!, is wastegate stuck open??

And there was me going over old graphs and fretting over the lag from my T3 on the RST!

That graph/power delivery is shocking Pablo- a 750rpm powerband? Ross' drag Evo had a wider curve than that!

Looks like the 438bhp run was aborted? Possibly due to wheelspin causing the unrealistic 'blip' in the graph?

[Bart]

right, I have dug out our power graph from 2012 when it produced 451bhp.

I have taken the graph and copied the power curve onto the one from yesterday, black line

http://i15.photobucket.com/albums/a385/ ... e6f0c8.jpg

anyone have any ideas?
no idea why I carnt copy the IMG

[pablo]

Now you know why we sruggle on track, when she comes on boost she's quick, but boy is she laggy.

It was aborted, but due to the guy watching the rev counter which can't keep up when the car comes on boost (itis 28yrs old). Instead of going by the shift light which is contolled by the omex.

Sitting here thinking about it and i've no idea if it has had any affect on the car, but. Since we changed the diffs from 3.62 to 3.92 (for better acceleration) the car has not been remapped. It's only ever been checked over to ensure fueling was good. Then we had that issue where we found out that the car was only boosting to 18psi.

Having fresh eyes look at the car has high lighted an area that needs sorting and i am still very happy about it. We were only there for just over an hour and we've been told hold off on the cam and valve springs and lets address this first.

But you can see why we thought we needed more revs from the engine

[pablo]

Here you go mate.

[gary@apt]

im going to really blunt mate and say stop pissing around with whos been tuning car.

if they been doing it cheap, for free, or for beer tokens,its not helping you guys!

its got to be time to pay a proper tuner to have a look and get to bottom of issues,

i know i said i dont have time to do much for you as it would mean starting from beginning but if it means you coming over for day(bringing all your parts/spares ) then lets arrange it.

is omex unlocked?? or passworded?

[pablo]

Omex is passworded but we have the password.

We now have a new tuner and Friday was the first time they saw the car. They wanted to see the car and put it on the dyno as a basic health check before doing anything.. They haven't seen any previous dyno sheets but said that they would expect to see the boost coming in about 1000-1500 earlier.

Thanks for your blunt reply, your opinion is most valued which is why i post these things. I will wait to hear from them next week to see what they say and take things from there. They have already stopped us buying more bits for the car including planning head work as they said let's sort the boost out first.

[Danny@APT]

Forgive me for being lazy and not searching back through the thread, but I presume the bottom end was built with greater-than-stock revs in mind (ie, ARP studs/nuts on the main and big-end bearings)? I'd hate for you guys to eventually fit the springs and cam only to have a rod fire out of the side.

Also, what spec was the turbo- GT30 was it? What was the exhaust turbine housing size?

I only ask, because I have a feeling that it's a similar problem to what I think I have with the RST [off topic bit] where ever since I had my stage 2 T3 recon'd, it's always felt laggier. Now, the only difference between a stage 2 and stage 3, is a larger housing to ultimately allow greater flow at the top, with the downside of making it laggier low-down. My suspicion is that during the recon, a .55 housing was fitted as a replacement for the cracked .48 and explains why all my graphs are now moved around 5-600rpm to the right on the scale.

So I'm thinking that either your's needs a smaller housing to harness the gas flow better and get it spooling earlier-on, or like Gary says- the wastegate spring is either to weak and being blown open by the exhaust gas or is sticking open and constantly bleeding air away from the turbine. Eventually, with high rpm, the airflow is great enough to overcome the 'leak' and get the turbo onto boost- by which time it's too late and you're at the limiter.

Granted, the Cosworth engine is not as efficient as an Evo lump, but it shouldn't struggle as hard as your's is to get a GT30 working.

I really hope you guys find the cause and get the power you've worked so hard for.

[pablo]

Bottom end was built with 500+ in mind.
Crank was skimmed and polished -.25 and then fitted with +.25 ACL Race beariings.
Crank, flywheel, clutch, pistons and rods all balanced and ARP bolts used.

Turbo is a GT3076. The only thing we DON'T know is what pressure of spring is in the wastegate.