MINI2

OneCleanCooper · Dec 21st, 2003, 11:48 PM

In 1.8Ts a 5 psi increase in boost can yeild as much as 40hp. so why do we such little gains from our 15% reduction pulleys?

bluemcs · Dec 22nd, 2003, 02:41 AM

Quote: Originally Posted by OneCleanCooper

In 1.8Ts a 5 psi increase in boost can yeild as much as 40hp. so why do we such little gains from our 15% reduction pulleys?

1. One is turbocharged and one is supercharged. Supercharged car has parasitic drag and decreased efficiency at higher boost levels, turbo's do not.

2. Stock -> 15% pulley does not give you 5 psi increase, more like 3-3.5.

3. I would think that boost increases/hp gains are not linear over the range. I don't know where the 1.8T starts?

More from the experts??

ZAMIRZ · Dec 22nd, 2003, 02:50 AM

blue covered it pretty well. Another thing to consider is that on a 1.8T 4psi may be 40hp in a certain rpm band, but what's important about the pulley upgrades on our car is they greatly increase the area under the curve........basically the hp/tq curve is just moved up, not staying the same througout most of it and then peaking at a larger number like most turbo motors that have had the boost increased.

ninjanick · Dec 22nd, 2003, 03:05 AM

Just want to reiterate what Zamirz said, "basically the hp/tq curve is just moved up" ... looking at peak horespower is great on paper, but the overall area under the torque curve is what people are looking for.

Not really sure if the Audi/VW chip upgrade that ups the boost gives 40hp, but when I had my 2001 1.8TQ with APR Stage 3 ... it wasn't much different than stock chipped with the K03 turbo. It was actually a little dissappointing.

Mugami · Dec 22nd, 2003, 08:54 AM

also and extra tid bit that may clear it up a bit on turbo vs SC .. the turbo can reach the 5psi down at lower rpms and maintain it thru the rev range. Hence the curve and where peak hp comes to play. with the SC the hp bar is a straight upward line from begining to end of pull. you dont get the extra 4 lbs untill it reaches top end.

To answer some from your other thread (not going into complaint stuff) search for a thread G-Tech before and after Mods. You gain about .5 a sec in 1/4 which is equal to only 1 - 2 car lengths for pulley and intake. Which was about the same for when i changed the exhaust only on my car. Only when you go up against the guys on the strip that are doing 14.5 or quicker will you be impressed with the difference the pulley makes. The guys with the JCW kit are only going the .5 faster than stock and thats with SC, Head, intake and exhaust mods. For Drag racing that .1-.5 second faster can win you the race but is not as visable as if you took it to a Road course or Auto-x event. Where the times can be 1 full second to 5 seconds faster for the lap which looks more impressive.

Times based on same driver before (15.5) and after mods (15.0 pulley) (14.7 with exhaust)

Have fun, Be safe and Keep MOTOV8N

Dec 21st, 2003, 11:48 PM	#1
OneCleanCooper MINI2 Newbie Join Date: Dec 2003 Local Time: 08:12 PM Posts: 12 Offline	How can an increase of 4psiof boost only yeild 10-20hp? In 1.8Ts a 5 psi increase in boost can yeild as much as 40hp. so why do we such little gains from our 15% reduction pulleys?

Dec 22nd, 2003, 02:50 AM	#3 (permalink)
ZAMIRZ MINI2 Regular Join Date: Mar 2003 Location: Woodland Hills, CA Local Time: 05:12 PM Posts: 132 Offline	blue covered it pretty well. Another thing to consider is that on a 1.8T 4psi may be 40hp in a certain rpm band, but what's important about the pulley upgrades on our car is they greatly increase the area under the curve........basically the hp/tq curve is just moved up, not staying the same througout most of it and then peaking at a larger number like most turbo motors that have had the boost increased. BRG/B S

Dec 22nd, 2003, 08:54 AM	#5 (permalink)
Mugami MINI2 Master Join Date: May 2002 Local Time: 09:12 PM Posts: 1,215 Offline	also and extra tid bit that may clear it up a bit on turbo vs SC .. the turbo can reach the 5psi down at lower rpms and maintain it thru the rev range. Hence the curve and where peak hp comes to play. with the SC the hp bar is a straight upward line from begining to end of pull. you dont get the extra 4 lbs untill it reaches top end. To answer some from your other thread (not going into complaint stuff) search for a thread G-Tech before and after Mods. You gain about .5 a sec in 1/4 which is equal to only 1 - 2 car lengths for pulley and intake. Which was about the same for when i changed the exhaust only on my car. Only when you go up against the guys on the strip that are doing 14.5 or quicker will you be impressed with the difference the pulley makes. The guys with the JCW kit are only going the .5 faster than stock and thats with SC, Head, intake and exhaust mods. For Drag racing that .1-.5 second faster can win you the race but is not as visable as if you took it to a Road course or Auto-x event. Where the times can be 1 full second to 5 seconds faster for the lap which looks more impressive. Times based on same driver before (15.5) and after mods (15.0 pulley) (14.7 with exhaust) Have fun, Be safe and Keep MOTOV8N 02 MCS DS/W (Totaled November 02 on Fall Folage Run) 03 MCS DS/W (See my MINI Profie for extensive list of mods)

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Dec 22nd, 2003, 02:41 AM	#2 (permalink)
bluemcs MINI2 Regular Join Date: Jan 2003 Location: East Local Time: 08:12 PM Posts: 77 Offline	Quote: Originally Posted by OneCleanCooper In 1.8Ts a 5 psi increase in boost can yeild as much as 40hp. so why do we such little gains from our 15% reduction pulleys? 1. One is turbocharged and one is supercharged. Supercharged car has parasitic drag and decreased efficiency at higher boost levels, turbo's do not. 2. Stock -> 15% pulley does not give you 5 psi increase, more like 3-3.5. 3. I would think that boost increases/hp gains are not linear over the range. I don't know where the 1.8T starts? More from the experts??

Dec 22nd, 2003, 03:05 AM	#4 (permalink)
ninjanick MINI2 Newbie Join Date: Dec 2003 Location: Los Angeles Local Time: 05:12 PM Posts: 16 Offline	Just want to reiterate what Zamirz said, "basically the hp/tq curve is just moved up" ... looking at peak horespower is great on paper, but the overall area under the torque curve is what people are looking for. Not really sure if the Audi/VW chip upgrade that ups the boost gives 40hp, but when I had my 2001 1.8TQ with APR Stage 3 ... it wasn't much different than stock chipped with the K03 turbo. It was actually a little dissappointing.

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