I have a 1.8T GTI that has run a best of email@example.com. This was with a GIAC chip, drop in filter, lower IC pipe, and bypassed power steering. All else stock. I recently installed a 3 piece set of Unorthodox pulleys. I was hoping for a .1/1mph gain, but ended up losing 1mph in trap speed (weather and altitude corrected). I have a few questions:
1) The weather was extremely cold when I ran the car with the pulleys. I have heard unsubstantiated rumors that the ECU will reduce performance during winter months to make the car perform equally throughout the year. Is this true? If it is, how can I get around it?
2) My other theory is that my DV has been slowly going bad. I replaced it with a Forge and will do some more drag testing to see if this is why I lost trap speed. I am still concerned about the ECU/cold weather phenomena though, and would like to include or eliminate it as a theory as to why my performance has suffered.
11-21-2000, 08:28 AM
The turbo loves cool weather. I also have a Garrett chip and the car pulls stronger the colder it gets.
11-21-2000, 09:59 AM
Didn't anyone warn you about the pulleys? There are dozens of archived posts on this. The only chip that is slower in the cold is a pile of junk.
11-21-2000, 10:08 AM
Throughout the whole pulley debate, not one person had dyno numbers or dragstrip times that proved pullys were bad or good. I have consistently seen .1/1mph from pulleys on other cars, and decided to try it on the 1.8T. I will be drag testing again this sunday to put some facts around this rumor.....
11-21-2000, 12:01 PM
I've posted many times on this topic, and have got mixed replies/responses/kudos and flames.
Here is some quantitative info-
1996 Integra GS-R 1.8L, header, exhaust, adj cam gears, fuel riser, intake - added Unorthodox pulley +2hp on the dynojet.
This was exactly what I got when I experimented with just removing the power steering belt, +2hp.
I have argued that this part is only for a race only setup where every ounce of rotational weight is necessary to get ahead of the competition.
On a daily driven Audi, too much is dependent on a proper pulley ratio (if this an underdrive pulley) - auto climate control, alternator charge, power steering, ABS and the ECU. If the ECU reads a drop in voltage this can be discovered using a VAG tool, and an error code will result.
I have heard from Miata friends that these pulleys have cause water pump failures as well.
In the other camp there was a poster who claimed 18hp with the pulley installed. I highly doubt this, for two reasons. By my calculations (I'm a chemist not a physicist) the original pulley had to be denser than plutonium to be THAT inefficient, second, do you really think the Audi engineers would use such an inefficient part that could concieveably put them ahead of the Beemer Boys without having to increase boost on the turbo?
The BEST you will get from one of these pulleys is the feeling that the A/C isn't on, 2-4hp.
As I have posted before, I will gladly recant these posts and my reasoning and buy a pulley myself if I see one set of NON-manufacturer provided before and after dyno runs.
If you really want to gain some hp in a rotational weight reduction go for that flywheel that was designed so any grandma (sorry to my grandmother) could work this gearbox.
11-21-2000, 12:11 PM
Again, while I agree with your logic and reasoning, I have only seen ONE unbiased test of pulleys on a 1.8T, and it resulted in significant power gains(+9 hp and tq). Email Billy Tylaska at firstname.lastname@example.org. He is one of the fastest 1.8T GTI guys on the net.
As pulleys seem to work on a myriad of vehicles that are just as complex as the 1.8T, I just can't see the logic in discounting them w/o any quantitative proof. I also agree with the fact that pulleys will not give more than 10hp or so, but I'm looking for every last tenth I can, as I'm trying to go 13.99 while retaining the stock ko3. ....Thanks again for a great discussion.
11-22-2000, 09:40 AM
Happy Thanksgiving! I'd like to see those plots, and the other mods on his motor to see how they work together.
You're the first to offer some quant info on the 1.8T, and seeing how people keep bringing up this topic, perhaps a FAQ can be made up if he wouldn't mind his dynos posted.
11-22-2000, 09:58 AM
Yep, the flywheel, even with the dual-mass trickness is still an anchor. But then it's a lot harder to replace, so they can't sell a zillion to the honda crowd.
Everyone like to post some outrageous supposition on hp values without a dyno. Lose some weight, replace the seats, and don't run pimp tires; the car will be quantitatively faster.
If you must replace the pulleys to be super 1/10 of 1% faster. Just get a non-AC belt, I best the EC sells some for stripped cars.
11-22-2000, 10:04 AM
Is if the car is really running lean. When it is cold, the intercooler is more efficient, and there is greater air density; all with the net influence of increasing the relative knock resistance.
These conditions also allow for greater fuel requirements to meet the lambda (more air needs more fuel). If there is not enough fuel, say because the inj. are running at >95% duty cycle, then the ecu cuts back. Or the open loop (full throttle) gets so lean that it overheats and knocks, reducing timing advance.
11-22-2000, 10:16 AM
I was looking for more gains through the pulleys. I'll post test results on Monday....
11-22-2000, 11:41 AM
My GSR sedan in its last configuration made 3 more HP and 1 more TQ across the board by removing the ps belt. (Final numbers on a dynojet were 173 HP and 124 TQ, new goal is 200 HP at the wheels) I have since removed the AC belt (and AC) as well as the whole PS assembly (pump, bracket, etc.). I also have the U/R crank pulley. I did not before and after that mod alone though. I'm actually having the U/R crank pulley machined since I don't need the AC or PS "places" for the belt anymore. More removed rotational inertia!
You have to remember that turbo motors don't act the same way as NA motors. I'm also guessing that the Audi 1.8 motor winds up considerably slower than an Acura 1.8 motor.
By reducing the reciprocating mass, you allow the motor to wind up/down faster. In a NA motor, that usually all you get, plus maybe a few extra horses. With a turbo, things change. By winding up faster, you increase the exhaust flow faster, which in turn makes the turbo spool faster, giving you more power sooner. I would think this would affect low-mid power range, and not top end.
Of course, I am theorizing on most of this, but it sounds about right:)