Turbo Lag After Upgrades ??
14 November 2014, 08:35 PM
#1
Turbo Lag After Upgrades ??
After fitting a set of Williams Motorsport tubular headers and matching up pipe, a Japspeed fmic and a 3" APS exhaust system im now spooling around 600rpm later. Turbo is a Md321t billet and car is a 2.0 v8 sti, does 600rpm sound about right after losing the tmic and std headers/up pipe ??
I knew the fmic would induce lag but how does the tubular headers and larger up pipe affect spool ??
Ps im not complaining as i gained 50bhp in the process and once it gets going it pulls noticeably harder and the revs fly up much quicker, oh and im now officially a member of the 400 club, settled for a safe 1.6bar and made 430bhp ( BIG THANKS to Mark at TDR in Warwick)
I knew the fmic would induce lag but how does the tubular headers and larger up pipe affect spool ??
Ps im not complaining as i gained 50bhp in the process and once it gets going it pulls noticeably harder and the revs fly up much quicker, oh and im now officially a member of the 400 club, settled for a safe 1.6bar and made 430bhp ( BIG THANKS to Mark at TDR in Warwick)
Last edited by Dubzy; 14 November 2014 at 08:37 PM.
14 November 2014, 09:10 PM
#5
The MD321T is suited to a 2.5 engine, however the tubular manifold will shift power to the right making it feel laggier but what you lose at the bottom you will gain at the top.
With the standard mani the car will feel like its peaked at about 6.5k rpm, however with the tubular mani the car will pull cleanly to the limiter
With the standard mani the car will feel like its peaked at about 6.5k rpm, however with the tubular mani the car will pull cleanly to the limiter
14 November 2014, 10:20 PM
#6
The MD321T is suited to a 2.5 engine, however the tubular manifold will shift power to the right making it feel laggier but what you lose at the bottom you will gain at the top.
With the standard mani the car will feel like its peaked at about 6.5k rpm, however with the tubular mani the car will pull cleanly to the limiter
With the standard mani the car will feel like its peaked at about 6.5k rpm, however with the tubular mani the car will pull cleanly to the limiter
For the record im more than happy with the turbo and was expecting lag when i purchased it and again with the last round of mods was just curious how the headers and up pipe affected spool and just confirmed what i thought. Only thing i dont really like and thats the noise lol
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15 November 2014, 12:32 PM
#13
15 November 2014, 01:06 PM
#14
You would obviously have to have the 3-bolt headers for it to fit - such as the GT Spec or RCM 3-bolt tubulars - so I'm guessing the uppipe flange must sit lower, so as to compensate for the taller 3-bolt uppipe???
Must admit, I didn't realise it was taller, though - weird.
Must admit, I didn't realise it was taller, though - weird.
17 November 2014, 12:07 PM
#21
Can somebody explain what affect the headers have regarding torque characteristics ?? is it the same as bhp as in shifting the power band to the right or does it have a different affect on torque as i gained a fair bit more bhp compared to torque ??
Last edited by Dubzy; 17 November 2014 at 12:10 PM.
17 November 2014, 12:23 PM
#22
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i have the same headers with the Harvey smith trick up pipe, it brings the spool in earlier and helps a lot, the headers have the tendency to produce more power than torque as the band is shifted. I've a 2.5 so it may have worked differently as I had them fitted to reduce the dip of torque to gain in power after 4.5krpm the car with the standard headers had a slight dip (could only feel it when on road). Once I changed the headers it made the torque and power smoother and pulls hard all the way till redline, I too favour the trick up pipe as it will net a good bit of spool once the map is tweaked to suit
17 November 2014, 01:43 PM
#23
i have the same headers with the Harvey smith trick up pipe, it brings the spool in earlier and helps a lot, the headers have the tendency to produce more power than torque as the band is shifted. I've a 2.5 so it may have worked differently as I had them fitted to reduce the dip of torque to gain in power after 4.5krpm the car with the standard headers had a slight dip (could only feel it when on road). Once I changed the headers it made the torque and power smoother and pulls hard all the way till redline, I too favour the trick up pipe as it will net a good bit of spool once the map is tweaked to suit
22 November 2014, 02:35 AM
#24
Hi there
I wouldn't personally use Williams Motorsport headers,I've used them only once and I wouldn't use them again on my car,if budget allow I would swap them for RCM or GT Spec
MDX321T is OK turbo for 2.0L,just really needs to use proper Up pipe as above Alyn said or you can try source older RCM Venturi Up pipe with which you can gain on spool up,but not as with Harvey trick Up pipe,as Williams Motorsport Up pipe is bigger and doesn't bring spool up to lower RPM,because is bit bigger,bigger or oversized Up pipe can cause lag
Hope this help
Thanks,Jura
I wouldn't personally use Williams Motorsport headers,I've used them only once and I wouldn't use them again on my car,if budget allow I would swap them for RCM or GT Spec
MDX321T is OK turbo for 2.0L,just really needs to use proper Up pipe as above Alyn said or you can try source older RCM Venturi Up pipe with which you can gain on spool up,but not as with Harvey trick Up pipe,as Williams Motorsport Up pipe is bigger and doesn't bring spool up to lower RPM,because is bit bigger,bigger or oversized Up pipe can cause lag
Hope this help
Thanks,Jura
22 November 2014, 03:10 PM
#25
Iv got the Hs up pipe improved spool massively. Tried and tested on many cars. Only person to sell these up pipes is alyn at as performance. Great mod accompanied by the right headers never heard of headers you have used. At times standard/ported headers work better with right up pipe. Will make massive improvement speak to alyn 0191 410 3770 his advice is second to none.
22 November 2014, 11:01 PM
#26
Hi there
I wouldn't personally use Williams Motorsport headers,I've used them only once and I wouldn't use them again on my car,if budget allow I would swap them for RCM or GT Spec
MDX321T is OK turbo for 2.0L,just really needs to use proper Up pipe as above Alyn said or you can try source older RCM Venturi Up pipe with which you can gain on spool up,but not as with Harvey trick Up pipe,as Williams Motorsport Up pipe is bigger and doesn't bring spool up to lower RPM,because is bit bigger,bigger or oversized Up pipe can cause lag
Hope this help
Thanks,Jura
I wouldn't personally use Williams Motorsport headers,I've used them only once and I wouldn't use them again on my car,if budget allow I would swap them for RCM or GT Spec
MDX321T is OK turbo for 2.0L,just really needs to use proper Up pipe as above Alyn said or you can try source older RCM Venturi Up pipe with which you can gain on spool up,but not as with Harvey trick Up pipe,as Williams Motorsport Up pipe is bigger and doesn't bring spool up to lower RPM,because is bit bigger,bigger or oversized Up pipe can cause lag
Hope this help
Thanks,Jura
The actual headers look a bit like gt spec and look well made to be fair and ive heard positive things mentioned about them on here in the past thats why i went for them. Ive spoke with A.S and i will be purchasing a Harvey up pipe to compare, to be fair the lag isnt an issue and there is no lag once you get going anyway, and i would rather have some initial lag if meant a compromise to my top end power. My car is now so much quicker and the revs fly up way quicker than before but because i fitted a few mods all together its difficult to know the gains i got from each.
I spool around 600rpm later now after also going from top mount to front mount and im guessing the majority of the loss is due to this, bus as stated it feels so much quicker now and it just keeps pulling in every gear and went from 380bhp to 430bhp so overall im well happy. If the Harvey up pipe can give me earlier spool without compromising the power i will be even happier
Last edited by Dubzy; 23 November 2014 at 12:00 AM. Reason: typo
22 November 2014, 11:02 PM
#27
Iv got the Hs up pipe improved spool massively. Tried and tested on many cars. Only person to sell these up pipes is alyn at as performance. Great mod accompanied by the right headers never heard of headers you have used. At times standard/ported headers work better with right up pipe. Will make massive improvement speak to alyn 0191 410 3770 his advice is second to none.
23 November 2014, 04:36 PM
#28
Scooby Regular
I had a TD04 , WRX on a 2.0 PPP I changed the uppipe first to a decat one but It did not significantly change the point of rpm when the TD04 spooled. However when it came in it torque was much stronger.
Then I swapped the WRX TMIC to a large aftermarket TMIC.
That did loose some spool on the TDO4 . Logical I think because the TD04 does not make high flow.
I went then to TD05 16g injectors pump and had the map done so then I had decent spool through volume of flow, but it came in 500 - 600 later than the original TD04 on PPP.
At the time I deliberately did not go FMIC as I was aiming at 300 Bhp and it would have been overkill for a TD05 16g . So I am wondering if a Sti TMIC would have been better bet than the 30% larger TMIC from CX racing ( which was also supposed to be for 400 hp )
I ported the TD05 , I had wrapped the Pipes too , but im still left thinking the volume of air needed to compress in the CX racing TMIC is not helping the spool.
The biggest winner has been to change the waste gate opening cycle I found my new Aftermarket China turbo was starting to open the WG at 0.25 bar standard is 0.5
First off I fitted the TD04 one back to the new TD05 turbo , which helped but was still not much of an improvement.
So tuning if your WG to open a touch later still would seem useful, obviously you need some choice so I ordered a Kinguwa one with 3 various spring rates to choose from. I guessed 0.8 ,1.0, 1.2 bar . but I havent fitted this yet , as while I was waiting for it to arrive , I used a MBC and the dam thing jammed , the turbo spiked well over 2 bar inside 2 seconds, I spun a bearing. Bad Lesson learned on a 10 pound part.
The PPP "high" flow cat of course still contributes a bit of lag , but as its illegal not to have one cat in the bag , so Im going to stick with it once im back on the road.
Then I swapped the WRX TMIC to a large aftermarket TMIC.
That did loose some spool on the TDO4 . Logical I think because the TD04 does not make high flow.
I went then to TD05 16g injectors pump and had the map done so then I had decent spool through volume of flow, but it came in 500 - 600 later than the original TD04 on PPP.
At the time I deliberately did not go FMIC as I was aiming at 300 Bhp and it would have been overkill for a TD05 16g . So I am wondering if a Sti TMIC would have been better bet than the 30% larger TMIC from CX racing ( which was also supposed to be for 400 hp )
I ported the TD05 , I had wrapped the Pipes too , but im still left thinking the volume of air needed to compress in the CX racing TMIC is not helping the spool.
The biggest winner has been to change the waste gate opening cycle I found my new Aftermarket China turbo was starting to open the WG at 0.25 bar standard is 0.5
First off I fitted the TD04 one back to the new TD05 turbo , which helped but was still not much of an improvement.
So tuning if your WG to open a touch later still would seem useful, obviously you need some choice so I ordered a Kinguwa one with 3 various spring rates to choose from. I guessed 0.8 ,1.0, 1.2 bar . but I havent fitted this yet , as while I was waiting for it to arrive , I used a MBC and the dam thing jammed , the turbo spiked well over 2 bar inside 2 seconds, I spun a bearing. Bad Lesson learned on a 10 pound part.
The PPP "high" flow cat of course still contributes a bit of lag , but as its illegal not to have one cat in the bag , so Im going to stick with it once im back on the road.
08 December 2014, 07:11 PM
#30
I had a new Harvey "trick"up pipe fitted today and not only has it increased spool and response but also i no longer have a kink/restriction in my inlet pipe against the inlet manifold due to the odd angle my turbo was sitting at due to the williams motorsport up pipe i had fitted. My new 3" exhaust system no longer vibrates through the car after heating and manipulating the japspeed downpipe i have fitted. Sorted a few small issues today but made a world of difference to the car and had a great drive home as always.
Big Thanks to Mark and co at TDR (Thwaites) cant recommend these guys enough
Big Thanks to Mark and co at TDR (Thwaites) cant recommend these guys enough
Last edited by Dubzy; 08 December 2014 at 07:12 PM.