BC Legacy feels slow

[Guest]

Hey guys, i recently got a BC5 RS

I'm assuming it has a VF8 turbo

It has 2.5inch exhaust with no cat although its 2.24 from diff back

It has an HKS BOV

It has a boost tap (unbranded) apparantly set to 10psi

It has an external wastegate to atmos, i think its TiaL and unsure of size or spring rate (gay)

When i floor it, it will reach boost by about 3.5 and usually spike to about 12psi followed by a gradual decrease to about 8 psi by about 6k. Between 4 and 6k it feels slow, doesn't put you back in seat at all.

is this normal for a relativly stock RS? Also, im keen to get rid of the BOV and plumb the wastegate back in as i'm not a ricer, would this make any difference?

Cheers

[rex-leggy]

its only 10 psi on a little midget turbo . they go nice but if your jumping in one from a faster car then it will feel slowish.

also if it has a vf8 it should be getting to full boost before 3500 . maby a boost leak somewhere.

changing the bov wont make it go faster . but it will run more economical and wont backfire as much ect.

edit : it sounds like it is a vf8 because of the boost decrease . small turbo's will do that also

[Guest]

Thanks for your reply, could just be a smallish turbo running out of puff.

Is there a way i can bypass the external wastegate so it uses the internal one as a quick test? At the moment the wastegate has a long vac pipe going to a T peice, one side goes to BOV which goes straight to WAIC, and other pipe goes to intake mani i think

[Guest DUSWLO]

you may have to get another manifold without a wastegate.ithink if u take the vacum source off the wastegate the exhaust pressure may still open the wastegate im not sure,

but if u wana stop it from runing like crap

disconect the boost tap.run a simple vacume like from your turbo nipple(compressor housing) down to your wastegate

whatever spring is inside thats what boost you will have,

[Guest]

I took the boost tap out and it would hit 8psi then drop to 7ish, felt even slower. Maybe i just overestimated the capabilities of a VF8.

[Guest DUSWLO]

lol from my memory a vf8 was a good turbo on a 1.8Lturbo.

not sure about a 2.0L.

and i think around 10-12psi will be maxing it out,

mayb try researching for an upgrade,

[BC5RA]

First, I wouldn't listen to anybody's advice who has so far posted in the thread.

Second, I'd look into a Chip upgrade. Most of these will raise target boost pressure to around 14-16psi.

[rex-leggy]

 rorz said:

Thanks for your reply, could just be a smallish turbo running out of puff.

Is there a way i can bypass the external wastegate so it uses the internal one as a quick test? At the moment the wastegate has a long vac pipe going to a T peice, one side goes to BOV which goes straight to WAIC, and other pipe goes to intake mani i think

sounds like your wastegate is plumbed up incorrect.

the bov should have its own line strait from the manifold.

i dont think youll be able to use the internal anymore , would depend how its been modified to be kept shut.

9/10 the internal flap will be welded shut but some people do put a large spring on them.

a chip upgrade would be a good thing to look into even with the vf8 and a chip they haul as for a standard car . just my opinion

[Guest]

Thanks for the replies, this has got me wondering about the setup of my external... i've never had one before so am unsure how they work.

At the moment, there is only one hose going to the EWG. This hose starts at the turbo (compressor?), runs through a boost tap, then goes to EWG. From what i can tell this is correct, should there be another hose connected to the other side of the wastegate though?

Also, my EWG 'probably' has an 8psi spring because earlier today i took the boost tap off and it ran at 8spi, unless it's still being limited to that by something else?

[madmike]

 BC5RA said:

First, I wouldn't listen to anybody's advice who has so far posted in the thread.

Second, I'd look into a Chip upgrade. Most of these will raise target boost pressure to around 14-16psi.

+1..

I ran my RS on a VF10 for a while.. Held 14psi rock steady and only ran out of puff in the very high range in 4th and 5th..

this was on the standard boost control via an ECU chip.

[Guest DUSWLO]

 BC5RA said:

First, I wouldn't listen to anybody's advice who has so far posted in the thread.

Second, I'd look into a Chip upgrade. Most of these will raise target boost pressure to around 14-16psi.

lmao what kind of advice is tht.if id like to see a vf8 on 16psi lmfao

[Guest DUSWLO]

why waste money on a chip.

if you wana get it running ok

simply run a vacum line from your turbo down to the bootom port of yor wastegate,get rid of the boost tap as there are SHIT.

whatever size spring you have inside,thats what psi you will be at.

a doubt a vf8 will be able to handle 16psi.if it can it wouldn be for very long.

[BC5RA]

 DUSWLO said:

why waste money on a chip.

if you wana get it running ok

simply run a vacum line from your turbo down to the bootom port of yor wastegate,get rid of the boost tap as there are s***.

whatever size spring you have inside,thats what psi you will be at.

a doubt a vf8 will be able to handle 16psi.if it can it wouldn be for very long.

Perhaps you should get your own car running properly first before you start giving advice, eh cabbage.

Humor me, Explain why you think its a waste of money for a chip?

Whats your experiences with VF8's etc?

[Guest DUSWLO]

 BC5RA']

[quote name='DUSWLO said:

why waste money on a chip.

if you wana get it running ok

simply run a vacum line from your turbo down to the bootom port of yor wastegate,get rid of the boost tap as there are s***.

whatever size spring you have inside,thats what psi you will be at.

a doubt a vf8 will be able to handle 16psi.if it can it wouldn be for very long.

/quote]

Perhaps you should get your own car running properly first before you start giving advice, eh cabbage.

Humor me, Explain why you think its a waste of money for a chip?

Whats your experiences with VF8's etc?

lol my car?mate my car is running like a dream to let you know,thanks for asking muppet

why waste money on something that doesnt need to be done!his standard ecu will be fine!

his car feels slow and runs like shit.

1st thing and (cheapest) thing would to be remove the tap and run a vac line from wastegate to turbo!and see what it runs on there.

a vf8 is a common upgrade for a mazda gtx and iv seen a few blow on 15psi easy.

but go ahead i was giving simple advice on how to get his car running and get a good base start

but ignorint people like you cant keep there mouths shut

so take bc5ra advice buy a "chip:" i garentee your call will run like shit

[CUDDAS]

have you got any pics of your set up?

condition of w/gate,- ive seen a few 'dutch' mounted ones down there that have rusted & partially siezed, boost guage, filter & strangle box ect, any 'check engine light' CEL's,

mine have all run ecu chips so cant say too much about factory std except that the Vf8 & vf10 wern't to shabby back in their day considering that most of the RS's had vf8's & that they were the fastest accelerating car you could buy for under 100k

[BC5RA]

 DUSWLO']

lmao what kind of advice is tht.if id like to see a vf8 on 16psi lmfao

[quote name='DUSWLO said:

why waste money on a chip.

if you wana get it running ok

simply run a vacum line from your turbo down to the bootom port of yor wastegate,get rid of the boost tap as there are s***.

whatever size spring you have inside,thats what psi you will be at.

a doubt a vf8 will be able to handle 16psi.if it can it wouldn be for very long.

lol my car?mate my car is running like a dream to let you know,thanks for asking muppet

why waste money on something that doesnt need to be done!his standard ecu will be fine!

his car feels slow and runs like s***.

1st thing and (cheapest) thing would to be remove the tap and run a vac line from wastegate to turbo!and see what it runs on there.

a vf8 is a common upgrade for a mazda gtx and iv seen a few blow on 15psi easy.

but go ahead i was giving simple advice on how to get his car running and get a good base start

but ignorint people like you cant keep there mouths shut

so take bc5ra advice buy a "chip:" i garentee your call will run like s***

I've owned 3 separate Legacy's with VF8's all of them ran 16psi - daily. All 3 I ran for over 50,000 kms I still own the 3rd.

Given that you probably weren't born back in 89, I don't think you could speak of plain bearing IHI VF8's and their strengths, Unless your talking about the shot units being put on manky GTX's.

I'd say there's a large number of guys on here who have run up to and over 1 bar on a VF8, probably on an RS or GT in the past/present.

[madmike]

 DUSWLO said:

why waste money on a chip.

if you wana get it running ok

simply run a vacum line from your turbo down to the bootom port of yor wastegate,get rid of the boost tap as there are s***.

whatever size spring you have inside,thats what psi you will be at.

a doubt a vf8 will be able to handle 16psi.if it can it wouldn be for very long.

I run a standard computer with a chip.. Have done for the 4 years i have owned the car.

My chip gave me 14-15 psi on the VF10..

The sister car to mine runs a VF8 and it sits on 16psi all day...(Again running a chip.)

VF8 is a great little turbo.

I run one on my 4ZC1 and it's been pumping out 14 psi for about 8 years without a problem..

[Guest]

Is this 'chip' everyone's referring to the speedlab one on trademe for $99? Sounds like it could be worth it. Also, should i plumb my external wastegate back in or get rid of it? Keeping in mind the gate is right near the radiator and the piping would have to go under the Xmember to get to the dump pipe.. making it very low.

Cheers

[madmike]

 rorz said:

Is this 'chip' everyone's referring to the speedlab one on trademe for $99? Sounds like it could be worth it. Also, should i plumb my external wastegate back in or get rid of it? Keeping in mind the gate is right near the radiator and the piping would have to go under the Xmember to get to the dump pipe.. making it very low.

Cheers

Speedlab chip is the one i have.

I would get rid of it dude.. unless your racing a gate is just wank factor..

Stick it back to orig is you best bet.. FOR NOW..

[Guest]

But surely an external gate plumbed back in is better than internal due to it's ability to hold boost better? or does that not matter with lower psi e.g. 10-15 psi

[madmike]

 rorz said:

But surely an external gate plumbed back in is better than internal due to it's ability to hold boost better? or does that not matter with lower psi e.g. 10-15 psi

With lower boost it is purely "Wank factor" Really you only need to look at external when your internal is not coping ie boost creep.

[Munkvy]

I agree on the chip. A long time ago I ran a VF8 and a chip definitely helped wake it up for very little money. One of the best value for money mods I did.

But first I would remove all the boyracer BS mods the car has, go to factory internal wastegate/manifold and make sure you have a decent exhaust (particularly downpipe) and a nice free flowing intake. Then chuck the chip on and put it on a dyno and see how its running.

Alternatively, if you have a little more cash I would highly recommend getting some yellow injectors off an STi and a Link ECU. Then you can really use the VF8 to its best potential.

Vivian

[Guest]

Thanks for your help, i went to order a speedlab chip but i read that you should have an 'upgraded exhaust and intake'. My exhaust is 2.5" from the turbo with no cat but the last 1/4 is only 2.25 and it's just a basic press-bent with flanges deal. Additionally, my intake is stock as i don't wish to use a pod filter.. do you think this will be ok?

Unfortunately i can't go back to internal gate as it's welded.

[madmike]

Dude i still use the standard intake.

Your exhaust sounds ok....

Check trade me for a VF8. They pop up every now and then cheap..

Put it in an see how she goes...