What HP can you expect from a unmodded S4?
09-28-2012, 02:27 PM
#46
Rennlist Member
"As for power-adders, don't believe everything that you read. Many folks report big numbers for x-pipes, but remember that they are swapping cats as well as adding the crossover. An x-pipe with new 100-cell cats (or no cats) will certainly outperform a set of melted, clogged factory cats. I do not know of anyone who has done the apples-to-apples comparison and just added the x-pipe without changing cats. I am not saying that x-pipes don't add hp, they do. But doing a proper before/after is not simple. "
Hey Jim....I do. Let me know if you would like to see the dyno sheets. I have hundreds from 85-86's, S4's and GTS's. I compared my crossover to Louie's and stock with and without cats, every option available including gutted factory cats. I can tell you the losses with each type of catalytic converter and cell density including the ones we had manufactured for our systems. The majority of my testing was on the same dyno, same day without even unstrapping the car. Just jacking it up and swapping while hot. No tuning was done to optimize any configuration either. When I tested against the factory cats I used the best set I had available out of at least a dozen sets unlike someone in across the pond...they started with a 240rwhp GT!
Hey Jim....I do. Let me know if you would like to see the dyno sheets. I have hundreds from 85-86's, S4's and GTS's. I compared my crossover to Louie's and stock with and without cats, every option available including gutted factory cats. I can tell you the losses with each type of catalytic converter and cell density including the ones we had manufactured for our systems. The majority of my testing was on the same dyno, same day without even unstrapping the car. Just jacking it up and swapping while hot. No tuning was done to optimize any configuration either. When I tested against the factory cats I used the best set I had available out of at least a dozen sets unlike someone in across the pond...they started with a 240rwhp GT!
Edit: your PM is full, please send me an email: jim at siriuscyber dot net
Last edited by jcorenman; 09-28-2012 at 02:51 PM.
09-28-2012, 03:11 PM
#47
Rennlist Member
Just wanted to add something I was told once and that I found interesting. It was back in 1996 when I was touring the engine factory at Porsche in Stuttgart. When we got over to where they dyno the engines, the guy in that area told us that the HP numbers they published were the minimum that they knew the engines would do. He continued to say that a lot of the engines of the same make would have a variance in power output. He stated that it was not uncommon to have two identical cars of the same year that performed differently. I’m not sure if he was only referring to the 911 series as that was about all they were producing at the time. There was a 993 twin turbo engine on the stand when we were going through. Pretty cool overall.
09-28-2012, 03:56 PM
#48
Drifting
Thread Starter
09-28-2012, 07:01 PM
#50
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Just wanted to add something I was told once and that I found interesting. It was back in 1996 when I was touring the engine factory at Porsche in Stuttgart. When we got over to where they dyno the engines, the guy in that area told us that the HP numbers they published were the minimum that they knew the engines would do. He continued to say that a lot of the engines of the same make would have a variance in power output. He stated that it was not uncommon to have two identical cars of the same year that performed differently. I’m not sure if he was only referring to the 911 series as that was about all they were producing at the time. There was a 993 twin turbo engine on the stand when we were going through. Pretty cool overall.
Also note that if a Porsche engine makes 5% more power in the dyno tests it is TAKEN APART !!!!! TO FIGURE OUT WHY !!!! There is not much variance from the factory numbers which are done on brake dynos at the flywheel.
09-28-2012, 07:27 PM
#51
Rennlist Member
Given a recent Hundai/Kia class action settlement for about 75 million dollars for engines NOT making advertised HP all car companies are very careful about advertised HP.
Also note that if a Porsche engine makes 5% more power in the dyno tests it is TAKEN APART !!!!! TO FIGURE OUT WHY !!!! There is not much variance from the factory numbers which are done on brake dynos at the flywheel.
Also note that if a Porsche engine makes 5% more power in the dyno tests it is TAKEN APART !!!!! TO FIGURE OUT WHY !!!! There is not much variance from the factory numbers which are done on brake dynos at the flywheel.
