Turbo: Hesitation Gremlins FIXED!!!

[WydRyd]

A HUGE sigh of relief and a couple beers later

This morning I ripped off the Intercooler and air filter to poke around to try to isolate the cause of my darn hesitation issues under boost.

Anything over 0.5bar and she'd spit and sputter in hesitation.

Anyway, I fiddle around, tracing some vacuum lines and this is what I find:







So yeh, the issue was the vacuum line that feeds the Protomotive Fuel Pressure Regulator literally blew itself off the "Y" piece behind the throttle body. Grrrrrrrrrr!

A bit of SuperGlue and cable tie around those connections will fix THAT problem FOR GOOD!

Went for a test drive at 0.8bar, ran perfectly.

Nervously set the EBC to 1.0bar, ran flawlessly.

Suffice to say, I'm over the moon today!!!!

Next step is to get the thing on the dyno to verify A/F ratios at 1.25bar

[turbocarrera]

YeeeeeeHaaaaaaaw!

[89turbocabmike]

1.25 bar! Man, I wish we had gas that could support that! What kind of octane rating is required at that level? What kind of HP boost can be expected for a .25 bar increase? any rule of thumb?

[WydRyd]

98 Octane, which I believe is equiv to your 93-94 Octane. I guess it's a combination of that as well as engine management, fuel capacity, intercooling etc...

Juan Ruiz has run between 1.3-1.4bar on pump grade 94 Octane

I *think* around 20 engine HP per 1.0-1.5psi, but don't quote me on that

[ssetek]

nice, what did i tell you
i figured it was that and kinda felt bad telling you to yank all the intercooler crap out an look at those lines but was pretty sure that was it.
good luck

ps those were lean missfires not hesitation.,..

[WydRyd]

luckily not serious enough to case catastrophic damage. Mind you tho, when it happened, I turned off the EBC and stayed at 0.5bar which was fine

Now to save for an upgraded clutch

[KLR]

We in the 951 world are well acquanted with the odd loose vacuum hose. You might try picking up a kit from Lindsey Racing for about $30 to replace all of those hard plastic hoses and rubber T's with purosil silicone lines and brass T's. You can get the hoses in black, so it looks perfectly stock. If one of these connections is loose, several others probably are as well...



BTY -- Lean misfires? I would have guessed that the car was running rich, as the vacuum leak was allowing boost (air) to escape while the CIS was still dumping roughly the same amount of fuel into the chambers, no?

[ssetek]

Originally posted by KLR

BTY -- Lean misfires? I would have guessed that the car was running rich, as the vacuum leak was allowing boost (air) to escape while the CIS was still dumping roughly the same amount of fuel into the chambers, no?

no this is a efi car and the vac line was off the fmu and will not add the extra fuel pressure to make the injectors fuel more and that little line doesent lose that much air.

[Craig 930 RS]

1.25 bar???

Be careful -

[raceman]

hey Merv,what other mods were needed regarding vacuum and emissions lines around the T-body to allow boosted operation? And for the brake booster? What information does Promotive give you about all that?any help appreciated,thanks