conrad Donating Members 40 Member For: 15y 5m 24d Gender: Male Location: In the Worksop Drinking Beer Posted 28/01/11 02:02 PM Share Posted 28/01/11 02:02 PM Ok all I have just got to tell you all something!!! I had just recently changed my Exhaust to a 4" Dump with a 3.5" exhaust and fitted a HDI GT2 cooler kit, I was experiencing some major overboost problems.I had connected a digital manometer to the intake manifold to measure boost pressures, with the 6 speed Manual gearbox in 4th gear under WOT ( Wide Open Throttle) my car was hitting 18.9 PSI on a 8 Psi Tune. So as you can see from those figures it overboosted 10.9Psi!!! that is double of what it should be making ( on my current tune)!!. I had recently purchased an exhaust housing from a forum member, and ported and smoothed it out and fitted a 36mm wastegate flapper. Porting the housing and fitting the flapper took me approx 4hrs (To get the gas flow correct) It took me 5hrs to remove my turbo last night and refit the newly modified exhaust housing.I plugged the manometer in today and I can say that the wastegate mod really works, the car was making 7.9psi on a 8psi tune as opposed to the 18.9Psi the day before, so I have successfully fixed my overboost prob once and for all. You cant just bore the wastegate out (Drill It out), you really need to do it correctly, proper methods need to be used to ensure the gas flow is going to be at it's optimum, I am now happy with the AF ratio's and I can safely say that this mod is really needed to control that overboosting XR6T ( Unless of course you go for an external gate). If you are interested in getting this done just let me know, I can do it at a price that is very competitive (For Feb only $280+Postage, you send me your housing and I port it out and fit an upgraded Garret flapper), just shoot me a pm. CheersConrad Lovett Link to comment Share on other sites More sharing options...
Kv! Donating Members 1,132 Member For: 14y 9m 17d Gender: Male Location: Eastern Suburbs, Melbourne Posted 29/01/11 12:13 AM Share Posted 29/01/11 12:13 AM (edited) Why not get a re-tune after the new mods?That way the car would be running much better and as safe as possible. Edited 29/01/11 12:13 AM by kvbaby Link to comment Share on other sites More sharing options...
conrad Donating Members 40 Member For: 15y 5m 24d Gender: Male Location: In the Worksop Drinking Beer Posted 29/01/11 01:56 AM Author Share Posted 29/01/11 01:56 AM (edited) Why not get a re-tune after the new mods?That way the car would be running much better and as safe as possible.Mate I will eventually get a retune, I still need to do a few more things. I need some deka 60's and a GSS340 Pump, I really dont see the point in getting a retune just yet. I'm happy with the AFR's (Data Logging is good for this). I had some pretty big performance shops tell me the problem was with my tuning and that the upgraded housing, wouldn't fix my overboosting problem, but as you can see from my first post, I have dropped my boost pressures from 18.9PSI to 7.9PSI, so the housing modification was in fact my problem and I'm stoked that my overboosting problem is finally fixed. Anyone that is starting to play around with their XR's should really get this done, I should have done this first, before any other mods. I spose it's like when you get an old car and fit a bigger engine too it, the first thing you should do is upgrade the brakes and suspension so it can cope with the extra power (You want too stop before you hit that tree). The same principle applies here, you really need to keep your engine safe stopping the damn thing overboosting, should really be one of the first things you do, there is no use getting a bigger exhaust, intercooler if your engine isn't going to make safe power.CheersConrad Edited 29/01/11 01:58 AM by conrad Link to comment Share on other sites More sharing options...
ratter Member 6,793 Member For: 18y 6m 6d Gender: Male Location: @ my laptop Posted 29/01/11 03:03 AM Share Posted 29/01/11 03:03 AM Good on you for having a go and sorting things out yourself, but your description is not quite correct.A tune may have sorted out your overboosting by droping the wastegate duty cycle at the rpm it was overboosting because of your high flow exhaust etc.If the duty cycle is down or very close to zero, that's when the port job needs to be done.There are plenty of T's out there with good boost control and good flowing exhausts and intakes with standard ports, it's normaly the association if good flowing hardware and a stronger actuator that leads to the wastegate being too small to control boost. Link to comment Share on other sites More sharing options...
ratter Member 6,793 Member For: 18y 6m 6d Gender: Male Location: @ my laptop Posted 29/01/11 03:13 AM Share Posted 29/01/11 03:13 AM What are you using to data log your AFR's? Link to comment Share on other sites More sharing options...
conrad Donating Members 40 Member For: 15y 5m 24d Gender: Male Location: In the Worksop Drinking Beer Posted 29/01/11 03:22 AM Author Share Posted 29/01/11 03:22 AM What are you using to data log your AFR's?I'm currently playing with a Innovate LM-2 link hereIt's pretty good I read some bad reviews about it but it seems to work well for now. Bought it from the USA (cheaper)Conrad Link to comment Share on other sites More sharing options...
ratter Member 6,793 Member For: 18y 6m 6d Gender: Male Location: @ my laptop Posted 29/01/11 03:28 AM Share Posted 29/01/11 03:28 AM They are pretty good.Have you got a bung in the exhaust for it or just a tailpipe sniffer? Link to comment Share on other sites More sharing options...
conrad Donating Members 40 Member For: 15y 5m 24d Gender: Male Location: In the Worksop Drinking Beer Posted 29/01/11 03:31 AM Author Share Posted 29/01/11 03:31 AM Good on you for having a go and sorting things out yourself, but your description is not quite correct.A tune may have sorted out your overboosting by droping the wastegate duty cycle at the rpm it was overboosting because of your high flow exhaust etc.If the duty cycle is down or very close to zero, that's when the port job needs to be done.There are plenty of T's out there with good boost control and good flowing exhausts and intakes with standard ports, it's normaly the association if good flowing hardware and a stronger actuator that leads to the wastegate being too small to control boost.Cheers for that extra info mate, so there are obviously a few things that can be done to help control boost, that I didn't know about. It seemed cheaper for me to port the housing and add a larger flapper (Fixed my problem). There isn't anyone that can tune the XR's here in Bunbury that I know of. Perth is 2 hours North of Bunbury, so it would have costed too much, and I'm one of those blokes who would rather learn and sort it out myself. CheersConrad Link to comment Share on other sites More sharing options...
conrad Donating Members 40 Member For: 15y 5m 24d Gender: Male Location: In the Worksop Drinking Beer Posted 29/01/11 03:35 AM Author Share Posted 29/01/11 03:35 AM They are pretty good.Have you got a bung in the exhaust for it or just a tailpipe sniffer?I have fitted the O2 sensor in the exhaust near the factory sensor (welded Bung). Yeah it's pretty good for the price, and seems to work well, I'm not looking forward to replacing the O2 sensor when it stuffs up (costs an arm and a leg). Link to comment Share on other sites More sharing options...
conrad Donating Members 40 Member For: 15y 5m 24d Gender: Male Location: In the Worksop Drinking Beer Posted 29/01/11 03:37 AM Author Share Posted 29/01/11 03:37 AM Ratter how do you log AFR's? Or do you just do everything on the dyno?Conrad Link to comment Share on other sites More sharing options...
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