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Hi all had my Hawk remapped running a vf34 turbo, don't seem to spool up very quick and feels a bit laggy, is it the way i drive lol or an issue with the map, cheers for looking
its going to feel different vs the td04 for sure. the td04 being a small turbo spools quick but runs out of puff and thats where you will feel the benefit of the 34. the midrange and top end should feel much punchier where the td04 would be tailing off. if your used to the immediate pull of a smaller turbo around town then you will have to get used to the feel of the 34. its by no means a laggy turbo as its a ball bearing turbo. your torque and boost graphs look spot on possibly the boost is conservative at 1.1 bar but the 34,s do make the power with less boost than say a vf35.
Yeah quick blasts round the town is where i notice the difference the most, will just have to get used to it then hey, still tempted to get a harvey trick up pipe and have a map tweak to see if it improves things a bit tho
it might gain you 300-500 rpm or so but it is a lot of expense for not much gain after factoring in the costs of the pipe and the map tweak. if your chasing that feel of a smaller turbo you would have been better with a hybrid td04 rather than the vf34.
Last edited by yabbadoo4; 29 January 2017 at 01:53 PM.
18 psi by 3250rpm, my Chinese 20g does 23.5 psi by 2900, but dynos do tend to make turbos spool slower, still I think I get 18 psi about 2600rpm. And I hold 20+ psi to the redline of 7200rpm.
My 20G on 2.5, 13 years ago without variable valve timing did 1 bar at 2600 RPM in 5th, 3000 RPM in 3rd. Dastek: 402 BHP at 6150 RPM, 391 lbft at 3750 RPM.
The graphs in this thread look like they belong to a 2.0, not a 2.5, but says on the chart it is a Hawkeye.
For context, a VAG 2.0T that weighs about the same, without changing the turbo can exceed the peak torque this car does from 2500 to 6500 RPM and make another 57 HP, so it is not surprising it feels a bit flat low down when the VAG has three times the torque at 2500 RPM with 0.5 litres less displacement.
I know that the Subaru isn't helped by compression ratio/port injection, single scroll long exhaust manifold, fixed exhaust cam timing, but still...
Last edited by john banks; 29 January 2017 at 06:57 PM.
Yeah m8 is for a 2.5 Hawk, mind you i did ask for a safe map and not to push it to much coz was getting paranoid about them 2.5 chocolate engine stories
Graphs look pretty good to me. Could have possibly added a little more boost as 18psi is 1.24 bar. You don't want to go above 1.35bar with the 2.5 engines as this can promote early failure, head lifting & head gasket failure etc. So it's got a sensible safety margin IMO.
Graphs look pretty good to me. Could have possibly added a little more boost as 18psi is 1.24 bar. You don't want to go above 1.35bar with the 2.5 engines as this can promote early failure, head lifting & head gasket failure etc. So it's got a sensible safety margin IMO.
Looks ok.
I don't think the engine was the limiting factor for boost here, the small turbo was.
like I say 1.6 bar in my 2.5 with a bigger turbo
I agree. Think as the OP said the map was done with a safety margin and IMO you should be able to squeeze a little extra boost from the VF34 if needed. But, I'd say it still looks fine.
My 20G on 2.5, 13 years ago without variable valve timing did 1 bar at 2600 RPM in 5th, 3000 RPM in 3rd. Dastek: 402 BHP at 6150 RPM, 391 lbft at 3750 RPM.
The graphs in this thread look like they belong to a 2.0, not a 2.5, but says on the chart it is a Hawkeye.
For context, a VAG 2.0T that weighs about the same, without changing the turbo can exceed the peak torque this car does from 2500 to 6500 RPM and make another 57 HP, so it is not surprising it feels a bit flat low down when the VAG has three times the torque at 2500 RPM with 0.5 litres less displacement.
I know that the Subaru isn't helped by compression ratio/port injection, single scroll long exhaust manifold, fixed exhaust cam timing, but still...
That just suggests that VW fitted the wrong turbo from the factory. What's the point in having a turbo that far exceeds your power target, all you are doing is introducing lag & cost? Subaru could have fitted a T36 to WRX's as standard, then we could have doubled the power with just a remap...
VF34 was being used on 1.8T 15 years ago with 320-350 HP results like Subarus, but hitting 1 bar at 2000 RPM and can rev to 7500 so 83% of your idle-red line is running good boost, but VF34 never reputed to be very reliable or have as good a power band as alternatives.
The OEMs size turbos to safely and consistently reach their power target at altitude, high temperature and low octane with a margin of safety for compressor wheel speed whilst meeting charge and exhaust gas temperature limits.
I just think id got used to how me car drove before running the TD04, was road mapped by Duncan so had no defined figures but he said it was probably around the 280bhp mark and was a lot more fun to drive on short trips out lol it still might grow on me, if not will have a rethink
29 January 2017, 11:34 AM
Reading a dyno graph
