VQ 304 - Cheap Street Fasts

[Dylan]

33 IAC steps? That's ok when warm but anymore and I'd open the throttle a bit. 10 to 20 I aim for.

[Dylan]

Had a look at the log, is there still no TPS connected? Is the wideband wired to the PCM?

Fix them up and post up another log with a matching BIN and we can help some more.

[[tuffvq]]

Hi Dylan,

I connected the wideband yesterday and took it for a proper drive, rather than just idle tuning in the garage. TPS does function but the common shaft on 2 x T/Bs means there's plenty of airflow at very low throttle openings. Something I'm working on.

It seems to be happy with the high levels of timing (32 peak), it was obviously quite lean high in the rev range as the factory VE levels fall off a cliff above 4000rpm. Managed to get it closer to 12.5-12.7:1 under 100kPa, but still needs more logging and fine tuning. I didn't get a lot of drive time in (around 15km).

However it doesn't seem too difficult to get close to right, it's all the little background items that I'll need time to get my head around.

The only problem I might have is looking at one of my logs it appears the speed readout isn't showing up correctly. It didn't log above 12km/h even though I was definitely doing more than that!

[immortality]

It will definitely handle a lot more timing in the low load areas when your just cruising around.

You could possibly try using V6 ecotec TB's as they have the hump that limits airflow a bit until you reach about 15% throttle. I think the VT 304 V8 TB's had the same hump too.

[Holden202T]

whats the pulse per km figure in the tune, you might need to change it from 6000 to 1250 ?

[[tuffvq]]

202T - Spot on.
It's sitting on 6248. Will adjust to 1250 or thereabouts and road test!

I'll play around with the intake manifold more once I get the motor out for its new lease on life.

[Holden202T]

yeah the VN dash divides the speedo signal by 5 and then sends that to the ECM, VR didn't and hense the number is 5 times larger, so when putting $11/12P into a VN/VP you usually need to change that .... +/- any difference in diff gears or tyre size you have made.

[[tuffvq]]

Ah great.
I've already got a Jaycar speedo corrector kit (4.11's), so I'll just play with the number until it works.

[psyolent]

tuffvq you shouldn't need it now. when you adjust the PPK the speedo shoudl start to read correctly dude.

[[tuffvq]]

Played with the car a bit more a few nights ago. Made some logs and had some queries but I haven't got the laptop with me so I'll post it up later.

Must be getting close on the power end of the tune as it baked the tyres really easily when I gave it some on a 'private road' that happened to require me going in a circle a few times.