First turbo

[rico]

Guys.

Ive just come to the conclusion that my first tubo doesnt do anything. I can hear it spinning up, boost is registered, but at the same time, the BOV(?) is very hissy when on turbo 1 ( a lot of splutter, escaping air etc.

accelleration when on turbo 1 is poor - my BM 330 had significantly more power for low speed acceleration.

Get to 4k revs though and its fine.

Does that sound normal, will i notice the first turbo at all. Any pointers ?

Thanks

Rico.

[geoffvalenti]

Hi

Unless you've got the car on a rolling road, I'd have thought it would have been difficult to determine that a hissing sound is coming from the BOV, whilst sitting in the driving seat.

If you're using the stock boost gauge, does it go right to the top of the scale when you give it full throttle, once the turbo starts boosting?

I'd never say that acceleration on the first turbo is poor http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/smile.gif Once you get to 4k and the 2nd turbo comes on line, you'll get another surge of power, but the VVT-i is pretty smooth in its power delivery in standard form.

I must admit it doesn't sound normal, you definately should notice the 1st turbo but if you've got a lot of hissing when on boost, you've almost certainly got a leak somewhere http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/sad.gif

I'd start by checking all the hose connections, they've got a tendancy to come off at the intercooler, usually the one underneath that you can't get at easily ?http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/mad.gif

If you think that the BOV maybe leaking its a good idea to check that too. ?You could temporarily block it off to test it, a quick blat up the road will tell you if it makes a difference. ?Don't leave it blocked off though, the turbos don't tend to like stalling ?http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/biggrin.gif

HTH

[rico]

Cheers Geoff.

I dont know the hissing is coming from the BOV, im just making an assumption as I know bugger all about turbo cars.

I know the Intercooler pipework is OK, as ive just installed a new FMIC and the problem is still evident. Ill check all the other hoses.

Acceleration is pretty mundane until 4k revs, then all hell break loose - maybe im just getting used to the surge of power.

Regards

[geoffvalenti]

I may be way off course here but just a thought http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/wink.gif. Has anyone maybe performed the ETTC (or TTC) mod therefore making the two turbos work in True Twin mode. This would give the symptoms of not a lot of boost/power below about 3000rpm or so, then a big surge of power from then onwards.

If you haven't had the car long, its maybe something to check. It's not a mod I've done myself, but by all accounts is pretty easy to do, just involving the swapping of a couple of actuator hoses.

Maybe a search on TTC (True Twin Conversion) could bring up some more details or pics to help you decide whether the car is working in sequential or true twin mode.
My guess is that if you can't feel the 1st turbo, its probably working in true twin mode.

I'm pretty sure (but someone please correct me if I'm wrong) that if the 1st turbo is blown, due to various pressure tanks and actuators, the 2nd turbo won't be able to come on line.

[Martin F]

Quote[/b] (rico @ Aug. 01 2004,09:59)]?I can hear it spinning up, boost is registered,
Do you know how much boost is registering at say 2000, 2500 & 3000 rpm ?

[rico]

I dont have a boost gauge yet, just the onboard one so cant really tell. Ill purchase one today to see.

[Martin F]

Errrr didn't you just say in your other thread that you had a hose pop off ? If you had a partial leak initially that could of accounted for this problem.

[rico]

Hi there.

Yup, i did have the hose pop off. Ive fixed that now; but im still not convinced that the first turbo does anything ( ie, ive not noticed this probelm since the new FMIC , its always been evident ).

I really need to sit in another Supra to see if im missing something, as it may just be normal Supra usage. Thats just such a massive surge at 4k revs, but notthing until then.

[Col]

rico, did you find out if this was a normal thing? I am thinking my car is the same. I don't really feel any boost intil 4000rpm. At 2000rpm it shows on my gauge as 0.5 bar and i can hear my BOV if i come off the gas. But i just dont feel anything until 4000rpm when it shoots up from 0.5 bar to just under 1 bar.

[alex h]

Don't forget guys that your limited to a turbo that can only shift ~160bhp till the second turbo comes online - so it's understandable that it could seem sluggish. The sequential system is designed to be 2 animals...the predictable easy to drive towny and the post 4krpm mile eater and porsche destroyer.
If you don't want that then fit a single http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/smile.gif

[Col]

i would love to do that http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/buttrock.gif but that aint gonna happen, at least for a few years anyway. I just love that thrust you get at 4000rpm http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/smile.gif

[rico]

Thanks for the reply Alex. that would explain why the car seems sluggish, my BM had approx 230 bhp which while not great, was alway there and its that initial response on the low RPMS im missing.

Im planning my moves to the single, but think its gonna be a good 6 months before i can afford the PHR 2+ turbo and associated AEM etc.

Every time i think its slow in the low RPM, i just do a sanity check in the wifes Frontera which soons sets my mind at rest.