So on a 900-1000whp Turbo car, im sure the stock throttle bodys are holding my car back but with these 70mm Throttle bodys whats the cons? do they leak, how is the drivability compared to stock? does it use the same TPS sensor or wire in a new one. Trying to get some thoughts on this before I drop $600 on them.
I have a set of 70mm Accufabs, granted I'm not boosted, the only thing I noticed over stock was the throttle responce was better. It may have a +5rwhp change as the real restriction is the POS intake on the Gen 2's.
For the record, power gain is unproven as nobody has ever done before/after dyno runs.
I have seen discussion to the extent that it was suspected of dropping horsepower on a totally stock engine. They seem to need to be aligned with other things that might require more flow like heads / exhaust / boost etc.
if someone wants to donate some 70s I'm sure Will and RSI wouldn't mind doing a before and after dyno once they have my ride finished and tuned...it will likely require a tuning change. but again...Will may be willing to do that to show some viable evidence of whether it is worth it or not.
well i have a built motor, ported heads and bigger valves but I left the intake manifold alone and stock gen 2 TB's so this winter I was going to port the intake manifold and do TB change as its the last thing i can do. I dont want to switch to a gen3 or gen4 intake mani because of the piping that would need changed and my fuel system change around.
Will@rsi Needs to chime in here im sure hes tested it the bigger TB's
well i have a built motor, ported heads and bigger valves but I left the intake manifold alone and stock gen 2 TB's so this winter I was going to port the intake manifold and do TB change as its the last thing i can do. I dont want to switch to a gen3 or gen4 intake mani because of the piping that would need changed and my fuel system change around.
Will@rsi Needs to chime in here im sure hes tested it the bigger TB's
I have heads/cam and just ordered a set from Sean on Friday. Who's doing your intake manifold? I was trying to do everything I could while the car was down and never thought of porting that.
on my Gen2 i tested stock TB's with headers, KN filters and cat back
then with 70mm TB's and picked up 15hp. on a stock car it wouldnt be much since the exhaust is restrictive. once i let it breathe, it really started waking up
this was on my dyno jet
i have dual 70mm accufabs on my twin turbo.. and i can tell a difference in throttle response.. but im sure they help move air.. at least more the the stockers
It takes a combination of other deep breathing mods to net any serious gains from larger TBs. I've heard several knowledgeable folks say that plenum volume is a handicap on the GEN 1 & 2 manifolds at high NA power levels.
I have heads/cam and just ordered a set from Sean on Friday. Who's doing your intake manifold? I was trying to do everything I could while the car was down and never thought of porting that.
I dont know yet, I do know that the ported heads were 1/16 of a inch bigger all the way around and now i need to "gasket" match the intake manifold so its not so restrictive heading into ported heads. I dont think i will touch the actual plentum part of the intake manifold just each runner i will have hoged out.
Im curious on a boosted car how much these TB's actually help on say 10lbs. vs stock TB's
I dont know yet, I do know that the ported heads were 1/16 of a inch bigger all the way around and now i need to "gasket" match the intake manifold so its not so restrictive heading into ported heads. I dont think i will touch the actual plentum part of the intake manifold just each runner i will have hoged out.
Im curious on a boosted car how much these TB's actually help on say 10lbs. vs stock TB's
at 9psi on my twin 78/.81 setup (with a safe 93 octane tune)... my viper made 783 whp and 750 fptq
what he is looking for is a viper that can be dyno'd before and after the TBs are in place, so let's say Scotty's at 9 psi did 783/750 with the TBs but 740/755 without. the best idea is to do it on the same car, same dyno, same day if possible to eliminate variables between shops, tunes, cars, dynos, temperatures, engine wear/damage etc.
I doubt any tuner would be willing to waste the time to R and R the throttle bodies and dyno the vehicle before and after. Unless you paid them to do it.
So on a 900-1000whp Turbo car, im sure the stock throttle bodys are holding my car back but with these 70mm Throttle bodys whats the cons? do they leak, how is the drivability compared to stock? does it use the same TPS sensor or wire in a new one. Trying to get some thoughts on this before I drop $600 on them.
You will have to increase the diameter of the mating surface on the intake manifold by 3/8". I did mine with the intake mounted on the car. I have several rotary tools, but the best was a dremel with a 3/4" drum. The type with replaceable sanding cylinders. It took approx 20 of the sanding cylinders. Use the coarse sanding sanding cylinders.
Stuff a rag in the opening and vacuum it out when you are done. If you do not open the manifold up there is no sense in installing the larger bodies.
So on a 900-1000whp Turbo car, im sure the stock throttle bodys are holding my car back but with these 70mm Throttle bodys whats the cons? do they leak, how is the drivability compared to stock? does it use the same TPS sensor or wire in a new one. Trying to get some thoughts on this before I drop $600 on them.
For your turbo car it does not make a difference.
Your compressor outlets are 2" or about 50mm, the piping in and out of your intercooler are 2". The piping before your current 2.5" TB's is 2.5".
It will make no difference if you get 70mm TB's.
It will affect your tune as far as the tip in is concerned ie bigger blade, larger surface area per degrees of rotation of TB shafts would be concerned.
Your compressor outlets are 2" or about 50mm, the piping in and out of your intercooler are 2". The piping before your current 2.5" TB's is 2.5".
It will make no difference if you get 70mm TB's.
It will affect your tune as far as the tip in is concerned ie bigger blade, larger surface area per degrees of rotation of TB shafts would be concerned.
Yea i was wondering about that as well with the piping.
Looks like Ill just pull the intake manifold off and port out each runner to match the Ported heads.
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