Turbo lag/BOV

[bitterberry]

Hey so I got my T1 a few weeks ago and its my first turbo car. I think I have some turbo lag, the car doesn't hit boost until about 3000 rpm. Any ideas on how I can reduce the lag?
Also, it's got a BOV on it, but I think the placement might be wrong and I'm not sure if it's impacting the car. This is it http://imgur.com/EzSiVBD it's on the right hand side of the PGMFI unit where there is some kind of plug on the stock engine. There's also a bleed valve fitted, could this be affecting the turbo lag in any way? Thanks

[KingCity]

Unless its leaking under boost then no the BOV will not be causing lag. 3000 rpm isn't far off the mark, usually the T1 will make full boost (10-11psi) at around 2600-2700rpm so if its taking a little longer then there is a chance the waste gate button shaft is seizing up & keeping the button from closing properly as this is the most common problem with the Turbo City's. One other thing could be that your ignition timing is a little too retarded, advancing the dizzy to the correct position will have a effect if turbo isn't the problem. All i can say is welcome to the Honda City World & enjoy learning for yourself.

[bitterberry]

Sweet thanks I'll have a look into those things. Would be nice to get full boost at that 2600-2700 rpm mark, what I meant is I usually don't even start hitting boost until 3000 rpm. Although I've got a spare motor that I'll be reconditioning and swapping into it, hopefully that will show a big change in power! Supposedly my current motor has 300,000+ km on it. Any advice on what to look for when reconditioning a turbo motor? Common problems?

[KingCity]

Wow yeah advancing the dizzy ain't gonna help you there, 3000rpm before seeing any positive boost pressure is likely to be a badly worn turbo &/or engine but check your waste gate first though, there is a thread about this on the site somewhere so check that to unseize your wastegate, saves me explaining it.

[bitterberry]

Alright I'll have a looksy for that thread, cheers!

[KingCity]

Oh & i was meant to ask once you see boost does it get up to around 10psi & hold it through to redline? If no & the boost slowly keeps rising till red line then its likely to be a massive leak between turbo & manifold, check all bolts & hose clamps are tight & check hose for splits & holes (hose from turbo to throttle intake).

[bitterberry]

Yeah once i get boost at around the 3000 rpm mark I can get about 10psi boost at 4000rpm and it holds onto that until red line, although I hear a kind of hissing noise like air coming out of a hose? I'm not sure if that's normal. Although I do sometimes get boost cut (or fuel cut) once its at that 10psi, feels like the car is rapidly lurching forward and backward, if that explains it?

[bitterberry]

Okay so today I had a look at the wastegate, it's not seized so that wasn't an issue. I took off the bleed valve that was on there. This reduced my lag so I hit boost at about 2500 rpm but I'm only getting 6 psi instead of the 9-10 that I was getting with the bleed valve. Feels a lot smoother though hitting boost that 500rpm earlier, and I don't have any boost cut anymore

[KingCity]

Mmmmm interesting. Yeah there is still an issue there, it still sounds like the wastegate botton is staying open a little bit, you may want to take the exhaust/cat off & check that the wastegate button is seating on the flange & also while you are doing that check the port/hole hasn't been oversized too far by previous owner/s as i had this problem when i die grinded out the hole (to stop boost cut from larger exhaust) to much which alowed the button to get caught on the edge at times which made it seem laggy cause late boost. As for that hissing then its likely to be coming from you boost controller & the controller is no doubt set to high causing it to boost cut which is around 1bar (14-15psi) on T1's. If you do take your exhaust off just give the turbo a good check over, check intake compressor & exhaust wheel for damage & shaft play.

[bitterberry]

I'll be sure to look at the button placement, when I checked I didn't have eyes on it just tested with my hand to see if it was seized, which it wasn't. Since I took my bleed valve boost controller off I'm only getting 6 psi boost, which from what I can tell is lower than it should be running without any boost controller. Thoughts as to why it won't get past 6 psi? I'll be looking to eventually get a bigger exhaust, probably when I put the other motor in. Is the bigger exhaust going to give me more boost or help with turbo lag? What can I expect?

[KingCity]

The exhaust wont help with lag, it will free up the power in the higher rev range which will create boost creep, that is why i opened up the wastegate port but its a very minimal amount, you can't really do a lot will them as the whole housing is small. I think that could be why honda put a restrictive exhaust on them to prevent this problem. If your turbo is alright & wastegate is working correctly then it must have a air leak in there somewhere & you will just have to pull it to bits until you find the problem, but if you have a spare motor then thats probably the better choice if you can't fix this issue.

[bitterberry]

I'll keep looking to see if I can find the problem, but I think from now I'll just more a less hold out until I can get the new motor reconditioned and get it that in there. Are you aware of any way I can improve the turbo on the other motor while keeping the same housing? Is it possible to get better quality turbines inside that housing or would I be looking for a straight recondition?

[KingCity]

Unless you plan on running more than 20psi the T1 turbo is fine, i find them to be just as good as the T2 turbo for under 20psi how ever the T2 turbo is the better one to have if you can get a hold of one without having to buy the motor to get it. The Rodeo turbo is a good upgrade which basically bolts straight on from what the forum says, i haven't done this. You can hi-flow you T1 or T2 but if possible use a T2 turbo as they have a better exhaust scroll which is more efficient at higher rpm from what i understand plus the T2 has a larger compressor cover which will suit the larger Subaru compressor. The turbine wheels are the same size as the T1 but the T1 has smaller exhaust scroll & intake cover. I have a hi-flow T1 turbo that i might sell early next year once i finish the drag season if i ever get to the track this season as i've missed 3 events due to engine issues. Probably want $500 for it but will come 2.5 inch exhaust & 38mm wastegate. The turbo cost $700 to hi-flow with Subaru WRX sized exhaust & compressor wheels, it works great & is only a tad laggier than the T1 & T2 turbos. Oh & if you do a hi-flow City turbo you will need to go after market wastegate because i couldn't run less than 20psi at top rpm with standard wastegate.

[bitterberry]

That turbo that you have would be great but I'm looking at getting this done this summer so I'll probably just get the turbo I have re cored and bore out the waste gate. Is there an ideal size exhaust for the t1's? I'm still deciding between 2.5" and 2.25", is 38mm waste gate a good size for a 2.5" exhaust with a t1 turbo?

[KingCity]

I would think anything 2" or bigger does the trick, i've only ever used 2.5" so i can't say what would be ideal, from what i understand the race city's used 2" but had no mufflers so nothing to restrict flow. As for wastegate size well 38mm is the smallest (common size) external type that i know of so yeah it does work fine.