When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
OT: DDP,, how did you get "Rocket Scientist" under your name?
Years ago a friend of mine was a moderator on here and made it that way without telling me, as a joke. At the time, the common saying on the forum was "it's not rocket science". It was quite fitting. Now I would prefer "Rocket Surgeon".
Years ago a friend of mine was a moderator on here and made it that way without telling me, as a joke. At the time, the common saying on the forum was "it's not rocket science". It was quite fitting. Now I would prefer "Rocket Surgeon".
Hi, I am thinking about upgrading turbo. I have modified k26/6. It produces 257 WHP at 1.15 bar at 5200rpm (Mustang Dynamometer) – the car was on dyno for three hours and was heat soaked even when I got it back after 35 miles on highway and sitting still for 3 hours, thus you could add couple of WHP on that number but not much). With the K26/6 there is too much back pressure, thus the boost is reduced to 0.8 bar at redline as more boost does not result in any additional power.
The hot side compressor wheel is replaced with larger one - based on size it is right in between OEM #6 and #8, thus you could name it K26/7 The cold side turbine wheel is Bullseye K26/6 billet drop-in wheel. Other supporting mods are 3 inch DP and 3 inch catless exhaust, modified intercooler (you could name it “garage made” stage 1 ), no AFM, as I have VEMS, Siemens DEKA 630cm2 injectors (will change to Bosch ones this season), TIAL 38mm WG that is controlled by VEMS through solenoid valve. Stock headers, intake manifold, head, air filter box (the OEM air filter box might be the biggest restriction in the intake). Also the engine is rebuild 1500 mile go with Wossner pistons and many other mods to reduce the No2 bearing oiling issue.
I have full boost of 1.15 bar at 3100 and 1 bar just below 3000 rpm, but I would like the turbo spool even earlier. I would also like to achieve that the turbo would remain efficient and operate efficiently at 1 bar till around 6000 rpm and get at least 15% increase in power compared to my K26/7 i.e. 300 WHP on the same dyno. As I am from Europe, for me it is cheaper to by Garrett turbo from Germany (e.g. GTX2867r would be around EUR 1400 including housing) than ordering bolt on turbos for 951s’ from US, as shipping and import taxes add around 35% to the initial price.
I see that some have commented that the smallest Garret turbo that you would like to put on 951 is GT30 series, however, there are comments that it reaches full boost quite higher in the rpm range than my goal stated above. Considering that I have a street car, I would be happy with the numbers above.
Please do not concentrate on the absolute numbers provided above as you cannot compare one dyno to another – let’s just say that I have highly modified K26/7 with billet wheel with very good tune, and my goal is to get at least additional 15% increase in power and increase the range of the turbo efficiency (no my torque line is flat from 3100 to 5100 rpm and I would like it to be flat from below 3000 to around 6000 rpm) and better response/spool, although already now I have no complains about the turbo lag although I cannot compare it to my DD that reaches max torque at 1500 rpm
Hi, I am thinking about upgrading turbo. I have modified k26/6. It produces 257 WHP at 1.15 bar at 5200rpm (Mustang Dynamometer) – the car was on dyno for three hours and was heat soaked even when I got it back after 35 miles on highway and sitting still for 3 hours, thus you could add couple of WHP on that number but not much). With the K26/6 there is too much back pressure, thus the boost is reduced to 0.8 bar at redline as more boost does not result in any additional power.
The hot side compressor wheel is replaced with larger one - based on size it is right in between OEM #6 and #8, thus you could name it K26/7 The cold side turbine wheel is Bullseye K26/6 billet drop-in wheel. Other supporting mods are 3 inch DP and 3 inch catless exhaust, modified intercooler (you could name it “garage made” stage 1 ), no AFM, as I have VEMS, Siemens DEKA 630cm2 injectors (will change to Bosch ones this season), TIAL 38mm WG that is controlled by VEMS through solenoid valve. Stock headers, intake manifold, head, air filter box (the OEM air filter box might be the biggest restriction in the intake). Also the engine is rebuild 1500 mile go with Wossner pistons and many other mods to reduce the No2 bearing oiling issue.
I have full boost of 1.15 bar at 3100 and 1 bar just below 3000 rpm, but I would like the turbo spool even earlier. I would also like to achieve that the turbo would remain efficient and operate efficiently at 1 bar till around 6000 rpm and get at least 15% increase in power compared to my K26/7 i.e. 300 WHP on the same dyno. As I am from Europe, for me it is cheaper to by Garrett turbo from Germany (e.g. GTX2867r would be around EUR 1400 including housing) than ordering bolt on turbos for 951s’ from US, as shipping and import taxes add around 35% to the initial price.
I see that some have commented that the smallest Garret turbo that you would like to put on 951 is GT30 series, however, there are comments that it reaches full boost quite higher in the rpm range than my goal stated above. Considering that I have a street car, I would be happy with the numbers above.
Please do not concentrate on the absolute numbers provided above as you cannot compare one dyno to another – let’s just say that I have highly modified K26/7 with billet wheel with very good tune, and my goal is to get at least additional 15% increase in power and increase the range of the turbo efficiency (no my torque line is flat from 3100 to 5100 rpm and I would like it to be flat from below 3000 to around 6000 rpm) and better response/spool, although already now I have no complains about the turbo lag although I cannot compare it to my DD that reaches max torque at 1500 rpm.
That's a big question. There's always the desire to have the quickest spool with the best top end. On an old turbo car you're just going to settle on the best compromise. It's not a good idea to compare the spoolup of a modern turbo car to the 951. They're in different leagues, partially due to the dual adjustable cam gears and partially due to the incredibly small turbo fitted on modern cars. I think your DD is spoiling you.
Have you thought about advancing your cam? This will improve spoolup and off-boost power at the expense of top end power. Advancing the cam by just 2* should improve your powerband slightly.
The Batmo wheel compressor is not the best design compared with other modern billet wheels. I followed forum threads on that wheel when it was developed several years ago and back then it didn't quite perform up to it's potential. A better choice for your goal is a billet extended tip wheel with 48 to 50mm inducer. Here's an example, http://www.ebay.com/itm/MAMBA-Billet...tWZZHs&vxp=mtr
Have you thought about advancing your cam? This will improve spoolup and off-boost power at the expense of top end power. Advancing the cam by just 2* should improve your powerband slightly.
The Batmo wheel compressor is not the best design compared with other modern billet wheels. I followed forum threads on that wheel when it was developed several years ago and back then it didn't quite perform up to it's potential. A better choice for your goal is a billet extended tip wheel with 48 to 50mm inducer. Here's an example, http://www.ebay.com/itm/MAMBA-Billet...tWZZHs&vxp=mtr
Thanks for the feedback! My spoolup with the current set-up is fine (for K26/6). I loose in the top end where the compressor wheel is too small (although the compressor exducer diameter is almost 6mm bigger compared to stock K26/6 (48mm vs 54mm) - However, I do not know the inducer size compared to OEM size.
The billet turbine wheel proposed by you is slightly bigger than OEM (both the inducer and exducer by 2 and 4 mm respectively IIRC), thus would need cold side housing modification to fit it?
After some research I did come to conclusion that from Garrett range two best options for my goals are GTX3071R Gen2 with A/R 61 compressor housing (should be able to hold 17 – 18 psi till redline with good spoolup and reaching both 14.5 psi and targeted 17 psi just above 3000 rpm) or GTX 2867R Gen2 with A/R 72 compressor housing – should reach 1 bar below 3000 rpm but probably would not be able to hold around 15 psi efficiently till the redline. Of course also the cold side is smaller thus the power in the upper midrange and the upper range would be significantly weaker compared to GTX3071R.
However, GTX2867R in theory would be good replacement to the stock K26/6 turbo for street driving, except it is not a direct bolt on thus I could not find anyone who would have installed it – if you have to do so much modifications, everyone wants a big power in the end (compared to the stock)
06-10-2012, 12:19 PM
