Do precats rob your torque?


my car been on the dyno when i made the 300WHP
And as u can c im not using all season tires i have NITTO 555R even harder 245-45-17
I no what im talking about dude i seen the gains and loses while tuning on the Apexi
That just sounds stupid.
And whats a picture of your car on the dyno ahve to do with making 300whp? Not saying you didnt but I really don't see why you even posted the picture.
I agree the apexi makes power though. How much is a different story. Seeing as though my 6mt 3.5 was at 12.1 afr @ WOT on the dyno I'm sure I could gain more power from it.
And whats a picture of your car on the dyno ahve to do with making 300whp? Not saying you didnt but I really don't see why you even posted the picture.
I agree the apexi makes power though. How much is a different story. Seeing as though my 6mt 3.5 was at 12.1 afr @ WOT on the dyno I'm sure I could gain more power from it.
Last edited by EL19; Oct 21, 2010 at 11:31 AM.
That just sounds stupid.
And whats a picture of your car on the dyno ahve to do with making 300whp? Not saying you didnt but I really don't see why you even posted the picture.
I agree the apexi makes power though. How much is a different story. Seeing as though my 6mt 3.5 was at 12.1 afr @ WOT on the dyno I'm sure I could gain more power from it.
And whats a picture of your car on the dyno ahve to do with making 300whp? Not saying you didnt but I really don't see why you even posted the picture.
I agree the apexi makes power though. How much is a different story. Seeing as though my 6mt 3.5 was at 12.1 afr @ WOT on the dyno I'm sure I could gain more power from it.
Just remember one think i made more power with just a apexi and tune then most of u with catdeletes and full exhaust j pipes and all that as of right now i have apexi to tune aem cold air intake UR crank pulley i made 300WHP now im installing my own custom precat deletes lets see what number i put on the dyno and one more thing im using NITTO 555r tires 245 45 17 drag radial tire bigger larger than stock .....its makes a difference
Car is good and strong. I have new tune with the same 8psi but in the old tune the a/f was in the low 11s across most of the powerband. With the new tune the a/f is a steady 12.5 from 4k to 6k which is perfect. I also have the meth up and running also. Havent gone back the dyno yet but we will and we'll turn the boost up a little more.
Car is good and strong. I have new tune with the same 8psi but in the old tune the a/f was in the low 11s across most of the powerband. With the new tune the a/f is a steady 12.5 from 4k to 6k which is perfect. I also have the meth up and running also. Havent gone back the dyno yet but we will and we'll turn the boost up a little more.
No, you NEVER lose torque. Stop being close minded and educate yourself. You can shift torque upwards in the rpm range and even that does no always happen. You're repeating an old wives tale that was busted 25 years ago.
I think the one who needs to educate themselves on that is u buddy no matter what car any NA car will lose tourque......
I agree you guys can go back and forth all day on this forum....but if theres some proof out there...someone post it up. I myself have been searching a ton of forums and google searches trying to find something to back either opinion up.
Don't make me think, it hurts my head...
Exhaust restriction or backpressure causes a loss of power period. Reason being is the piston on the exhaust stroke has to push exhaust out of the cylinder. The engine pumps exhaust out of itself and down the exhaust. This is one part of scavenging.
The other reason is if the exhaust is tuned just perfect, the velocity can cause a sort of "suction" or scavenging effect where it helps empty the cylinder more thoroughly of exhaust. This is beneficial because any exhaust left over that does not make it's way out will contaminate the intake charge and you lose power.
What some people are not getting is that even if you have 0 backpressure in the exhuast you will still have pressure in the exhaust port of the heads where gasses are still expanding. In fact, they're still expanding slightly right out of the head. This is one reason why turbochargers are mounted as close to the head as possible for better spool.
Basically by freeing up the exhaust you make it easier for the engine to pump exhaust out of itself and to the tailpipe. This is true 100% of the time. Obvioiusly at low rpm there is not as much flow so the gains are minimal. At low rpm and throttle there is not much exhaust flow so the factory exhaust won't be much of a restriction. As you get into the throttle and you produce more exhaust and at a higher rpm the factory exhaust becomes more restrictive with the extra flow and you start to see more gains. Some people mistake this as a loss in low end when in reality it gains less at the low end but does not lose anything.
You get gains everywhere but at low rpm since the factory stuff is not restricting much, it may not be measurable.
As for scavenging, it's not an issue with the TL. For starters, all of the merging is done inside of the heads. We have a single exhaust port going straight into the convertor or PCD. It's not something you have to think about. I would focus more on the way the two banks of cylinders are merged at the j-pipe for scavenging than anything else. An equal length of pipe would be beneficial as would extending the length of the separate banks until they merge together.
Exhaust restriction or backpressure causes a loss of power period. Reason being is the piston on the exhaust stroke has to push exhaust out of the cylinder. The engine pumps exhaust out of itself and down the exhaust. This is one part of scavenging.
The other reason is if the exhaust is tuned just perfect, the velocity can cause a sort of "suction" or scavenging effect where it helps empty the cylinder more thoroughly of exhaust. This is beneficial because any exhaust left over that does not make it's way out will contaminate the intake charge and you lose power.
What some people are not getting is that even if you have 0 backpressure in the exhuast you will still have pressure in the exhaust port of the heads where gasses are still expanding. In fact, they're still expanding slightly right out of the head. This is one reason why turbochargers are mounted as close to the head as possible for better spool.
Basically by freeing up the exhaust you make it easier for the engine to pump exhaust out of itself and to the tailpipe. This is true 100% of the time. Obvioiusly at low rpm there is not as much flow so the gains are minimal. At low rpm and throttle there is not much exhaust flow so the factory exhaust won't be much of a restriction. As you get into the throttle and you produce more exhaust and at a higher rpm the factory exhaust becomes more restrictive with the extra flow and you start to see more gains. Some people mistake this as a loss in low end when in reality it gains less at the low end but does not lose anything.
You get gains everywhere but at low rpm since the factory stuff is not restricting much, it may not be measurable.
As for scavenging, it's not an issue with the TL. For starters, all of the merging is done inside of the heads. We have a single exhaust port going straight into the convertor or PCD. It's not something you have to think about. I would focus more on the way the two banks of cylinders are merged at the j-pipe for scavenging than anything else. An equal length of pipe would be beneficial as would extending the length of the separate banks until they merge together.
Exceptions would be rotories and 2-strokes. Some very finely tuned specialized engines such as F1, high end drag racing, etc have every component working in harmony including exhaust scavenging but it's just not something that plays a significant part in a TL. Free up as much restriction as you can and don't worry about anything else.
TL-S you failed to provide any legitimate proof.
I will give you the benefit of the doubt, as some people just simply cant convey their thoughts onto paper.
When you get your ride dyno'ed come back and post up the numbers. before and after, with and without the tune.
I will give you the benefit of the doubt, as some people just simply cant convey their thoughts onto paper.
When you get your ride dyno'ed come back and post up the numbers. before and after, with and without the tune.
Yo now ur getting dumb man i seen it with my own eyes man dont tell me what i have seen and havent bro stick to ur stuff i stick to mine ......last thing im say ......REMOVING CATS WILL MAKE U LOSE TORQUE.................
^HA! i was thinking the same thing and waiting for someone to post that up. classic cool...
sorry i don't have anything insightful to add to this thread, other than sonnick read my mind.

sorry i don't have anything insightful to add to this thread, other than sonnick read my mind.
This is so much waste of time, energy and nerves....and you guys need to stop asking him to post up dyno sheets, because they're irrelevant.
A dyno sheet, whatever numbers it may produce can't go against mechanical science. Especially his sheets.
No one is saying that the Apexi couldn't be installed in the car and wouldn't work.
We've been down this road before...there's nearly nothing for you tune in N/A form in the TL with pump gas. NOTHING! never mind the outrageous numbers claimed.
See, if you knew a thing or two, or in fact stopped and took the time to educate yourself on the matter, than maybe you would question your numbers also. But you don't do that. Your tuner straps your car to a dyno that you know nothing about, pulls a few runs, prints out a graph with numbers on it, and there you have it. That's all it is to you.
I can put my life on the fact that if you went to some different dyno and somehow you got 350-400 whp, you'd be claiming that too, and swear by it day and night. See, dyno numbers don't always say much, especially when you get a TL-s and throw it on a dyno in stock form, and you get something like 270 whp...that's telling you that there was only 16 hp loss through the drivetrain. Then after a few tweaks, you run it again on the same dyno, and you now get 280+, pretty much all the crank hp you managed to push to your wheels with almost no mods whatsoever... My friend, numbers were wrong to begin with, and that leads to more wrong numbers. This is what happened to you when you came in here with your claims... again WE WENT OVER THIS, and you got banned because of your behavior for it, if i remember correctly.
I will mention to you again, that in your TL's stock form, there was nothing for you to tune in pump gas. Correct me if I'm wrong, but I think you also mentioned that Ignition couldn't be adjusted with the apexi. So, what on this earth did you tune? Even if ignition could be adjusted, and let's say it CAN, what are you going to do with it? The car detonates as it is.
Add more fuel? for what, so it can run rich? Because that's what will happen with the lack of additional air/oxygen.
Unless you do some really heavy engine work, there's not much to tune with in stock form, and nowhere near getting the numbers you've claimed.
And please stop saying "I got it on the dyno, the sheet, the screen", because I really don't give 2 shits where you got your numbers. There're not correct!
And also stop claiming what you've done with the Apexi no one else has done with many more mods..again, what you've done is a big NOTHING. That's just not how it works, not the way you think. It never has and it never will.
A dyno sheet, whatever numbers it may produce can't go against mechanical science. Especially his sheets.
No one is saying that the Apexi couldn't be installed in the car and wouldn't work.
We've been down this road before...there's nearly nothing for you tune in N/A form in the TL with pump gas. NOTHING! never mind the outrageous numbers claimed.
See, if you knew a thing or two, or in fact stopped and took the time to educate yourself on the matter, than maybe you would question your numbers also. But you don't do that. Your tuner straps your car to a dyno that you know nothing about, pulls a few runs, prints out a graph with numbers on it, and there you have it. That's all it is to you.
I can put my life on the fact that if you went to some different dyno and somehow you got 350-400 whp, you'd be claiming that too, and swear by it day and night. See, dyno numbers don't always say much, especially when you get a TL-s and throw it on a dyno in stock form, and you get something like 270 whp...that's telling you that there was only 16 hp loss through the drivetrain. Then after a few tweaks, you run it again on the same dyno, and you now get 280+, pretty much all the crank hp you managed to push to your wheels with almost no mods whatsoever... My friend, numbers were wrong to begin with, and that leads to more wrong numbers. This is what happened to you when you came in here with your claims... again WE WENT OVER THIS, and you got banned because of your behavior for it, if i remember correctly.
I will mention to you again, that in your TL's stock form, there was nothing for you to tune in pump gas. Correct me if I'm wrong, but I think you also mentioned that Ignition couldn't be adjusted with the apexi. So, what on this earth did you tune? Even if ignition could be adjusted, and let's say it CAN, what are you going to do with it? The car detonates as it is.
Add more fuel? for what, so it can run rich? Because that's what will happen with the lack of additional air/oxygen.
Unless you do some really heavy engine work, there's not much to tune with in stock form, and nowhere near getting the numbers you've claimed.
And please stop saying "I got it on the dyno, the sheet, the screen", because I really don't give 2 shits where you got your numbers. There're not correct!
And also stop claiming what you've done with the Apexi no one else has done with many more mods..again, what you've done is a big NOTHING. That's just not how it works, not the way you think. It never has and it never will.
i dont no where u get ur info from i really dont i mean i strapped the car the first time the fn dyno after correction said 261 which to u fn people is impossible this is what pisses me off then my tuner was messing with the APEXI after all corrections the dyno showed 287 that was after like 10 minutes of messing with the APEXI after trying and trying got it a 297 so dont tell me its not possible if i did it but dont worry i dyno next week and ill make a special video just for u opel.........
Ok, you're missing the whole goddamn point...
The dyno can show 500 hp, but it doesn't mean that your car's actually making that power...get this through your head!!!!
Seriously man, you need to stop with this shit...you triggers some unhealthy arguments.
The dyno can show 500 hp, but it doesn't mean that your car's actually making that power...get this through your head!!!!
Seriously man, you need to stop with this shit...you triggers some unhealthy arguments.
i dont have to stop anything man im telling u what i made but im ganna make the video just for u cuz u c to u is ok to mke ur bs hp but everyone else is impossible look man im at work i gatta finish my stuff ull b back next week show u what up .......till then dude go educate urself on real shit dude .....
i dont have to stop anything man im telling u what i made but im ganna make the video just for u cuz u c to u is ok to mke ur bs hp but everyone else is impossible look man im at work i gatta finish my stuff ull b back next week show u what up .......till then dude go educate urself on real shit dude .....
I don't care to see your video because it proves absolutely nothing, nor do I even care for any proof from you at this point.
I don't care to see your graphs, because they prove nothing, and I don't care to see pictures of your car either, because they don't prove anything.
You're proof enough that nothing you show can prove anything
Now stop typing because I'm having a hard time trying to figure out where your sentences end, and where the new one starts. Struggling to put it together ovaheaaa.
Dude ur not to far from me man we can meet up u can see what my car has shit we can even line it up them 375HP dont scare me lol OPEL on some real shit man come watch me dyno next week and ull change ur mind about what u saying






: whyme:
This kinda shit^^^^^^^^ Opel, IHC Keep on keeping on man "This old fart appreciates all you give to this site"...I've learned a ton just reading all the input you provide
THX
Last edited by lowbudgetTL; Oct 21, 2010 at 04:41 PM. Reason: I can't spell
Am I the only one with a massive headache after reading through this thread? I'm sorry, but first of all, 27-yr-old TL-S121 with a "fast fn TYPE S," please use periods and other punctuation when typing ... really helps others in comprehending what you're trying to convey
IHC and Opel has provided explanations upon explanations to prove their point which is that removing cats does NOT necessarily decrease torque ... you say otherwise because of "what you've seen on the dyno"??? This is from what I could understand ...
Anyways, back to the point ... they provided information/reasoning to back up their case ... where is your knowledge-basis of what you're saying? I mean arguing on public forums is a common thing, but if you're going to make a point, back it up with some information (I'm not asking for any dyno sheets or systematic reviews or anything). Otherwise, you're going to have people on your case for being a cocky, arrogant newb without being able to provide any useful information other than "I've seen that, i've seen this" ...
IHC and Opel has provided explanations upon explanations to prove their point which is that removing cats does NOT necessarily decrease torque ... you say otherwise because of "what you've seen on the dyno"??? This is from what I could understand ...
Anyways, back to the point ... they provided information/reasoning to back up their case ... where is your knowledge-basis of what you're saying? I mean arguing on public forums is a common thing, but if you're going to make a point, back it up with some information (I'm not asking for any dyno sheets or systematic reviews or anything). Otherwise, you're going to have people on your case for being a cocky, arrogant newb without being able to provide any useful information other than "I've seen that, i've seen this" ...
Am I the only one with a massive headache after reading through this thread?
...
IHC and Opel has provided explanations upon explanations to prove their point which is that removing cats does NOT necessarily decrease torque ... you say otherwise because of "what you've seen on the dyno"??? This is from what I could understand ...
...
IHC and Opel has provided explanations upon explanations to prove their point which is that removing cats does NOT necessarily decrease torque ... you say otherwise because of "what you've seen on the dyno"??? This is from what I could understand ...
IHC and Opel have given their explanations to explain their point to the fullest, which btw, is the good reading in this thread, and TL fn Fast has only explained his argument by saying "Yo, i seen it on the dyno sheet!" and "all mustangs and hondas do the same". Yea, that doesn't work, sorry...
GAME OVER
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I don't know why you're trying to argue TL-S. You've seen things, you've been told things. These guys KNOW these things. You're so ignorant at the matter in hand. All we ask is a simple dyno sheet or a 1/4 sheet. It is not that hard, and you keep saying my tuner did this blah blah he's the best on the planet. No offense to libert, but I don't care how good your tuner is, I don't care if he is only tuner on this planet, if you can't show any proof, don't say you can achieve anything. This goes back to our old thread when you talked about the Apexi Neo tune and showed no proof. All you said was that you achieved 300 WHP. If I came on the boards and said I put a shitty sticker on my car and it made 600 WHP and didn't post even a PICTURE OF THE STICKER, my point from then on are invalid until a picture is shown. Pertaining to the topic on hand, the pre-cats DO NOT lose torque. It is fundamentally and physically impossible. I'd do some Calc/Physics for you (if there is any), but I'm not going to because you won't listen to anyone, but your "tuner".
If you're so hard, lets meet at a track. I'd love to race you with my 900WHP Nova, let me know if you're so eager to show off.
If you're so hard, lets meet at a track. I'd love to race you with my 900WHP Nova, let me know if you're so eager to show off.
Last edited by TheChamp531; Oct 21, 2010 at 07:02 PM.






hahahahha
Thats all the car knowledge you need right there man. the Alpha and the Omega