62 mm vs. 70 mm t/bodies

[john evans]

anyone have any dyno experience with h.p results from a 62 mm t/b to a 70 t/b.is the upgrade worth it on a modified tta.

 

[TurboTnZ06]

Turbo magazine did it to a stock GN and they found that it did not make any more power. The stock TB is good for 9's. Use the money elsewhere in the car, ie an RJC powerplate or something. I'm using a stock unmodified throttle body. See my site in my sig for more info on my car I think heads are the first place to try to increase airflow on the 3.8L after the DP/IC/catback and pre-turbo air intake mods have been done...

 

[john evans]

thanks for the reply.

 

[VadersV6]

Yeah i could see a bigger TB gaining no extra power on a stock GN. I think once youve done alot to increase airflow, the TB would probably help. At the very least it can make the car more fun on the street cause it takes so much less throttle to get the car moving.

 

[DonnieShort]

Turbo magazine did it to a stock GN and they found that it did not make any more power. The stock TB is good for 9's. Use the money elsewhere in the car, ie an RJC powerplate or something. I'm using a stock unmodified throttle body. See my site in my sig for more info on my car I think heads are the first place to try to increase airflow on the 3.8L after the DP/IC/catback and pre-turbo air intake mods have been done...

9's? It's hard to say about that but look under the hood of any of the TSM guys car and most likely you will not find the stocker there. Usually the stocker is good until you get into the 10's, then a bigger tb could be useful. But if you aren't that fast it wouldn't benifit you much by going larger, but it will not hurt you though ( I've had alot of big time guys personally tell me that ) just some bling and that's it.

 

[TurboTnZ06]

9's? It's hard to say about that but look under the hood of any of the TSM guys car and most likely you will not find the stocker there. Usually the stocker is good until you get into the 10's, then a bigger tb could be useful. But if you aren't that fast it wouldn't benifit you much by going larger, but it will not hurt you though ( I've had alot of big time guys personally tell me that ) just some bling and that's it.

I agree, can't really hurt to go bigger, just money could be better spent somewhere else until you are well into the 10's. Over the years I've heard of ppl going 9's on the stocker. I've trapped a best of 126.48 mph on the stock TB.

 

[steve hughes]

Don't know when a bigger tb is needed but i can tell you i have run 9.41 at 141 on a 62. Spend your money on other things.

 

[John Wilde]

I don’t think it is the first thing you should buy, but if you have run out of bolt ons and you are making 600HP plus it will make more power.
Ken Duttweiler dyno tested an improvement. If I was not tired I would go into the achieves (my garage) and give you the exact numbers.
.

 

[GNVYUS 1]

I could of sworn ESP did a dyno of a bunch of parts years ago and this mod was done towards the end and picked up over 20HP and 30TQ at the wheel.

70mm TB compliments other mods very well, but definitely not on a stock car or slightly modded car IMO.

 

[Turbo6Smackdown]

you say it couldnt hurt? on a stocker? sure it could. theres a writeup somewhere on my board, that wrote of someone doing a step by step dyno tune on a stock turbo t, and he bolted on a bigger tb and it TOOK some of his response away. and as far as a stock tb doin 9's? im sure it could be done, but im sure only by the likes of cal hartline or mr. conley. you rarely see stock tb's on fast tr's. though, that would be the absolute last mod i would do to a near stock tr. do the basics first.

 

[DonnieShort]

you say it couldnt hurt? on a stocker? sure it could. theres a writeup somewhere on my board, that wrote of someone doing a step by step dyno tune on a stock turbo t, and he bolted on a bigger tb and it TOOK some of his response away. and as far as a stock tb doin 9's? im sure it could be done, but im sure only by the likes of cal hartline or mr. conley. you rarely see stock tb's on fast tr's. though, that would be the absolute last mod i would do to a near stock tr. do the basics first.

This has been discussed here many times. Unless you are making pretty big power a bigger tb wont show much if any gain. But most fast cars will use at least 62mm. Would it hurt a bone stock car, I just don't know the answer to that. What I do know is when my set up was a bolt on only set up, I put on a PTE upper and 70mm tb. I immediatly noticed improved throttle reponse. But my car was in the low 11's at the time too. I'm not endorsing someone to buy one at stock type level. It is a pretty pricey add on for no more than it gives. It looks good though . I would make it the last thing on the list to do. But if you are in the 11's and really wanted one, it will not hurt you. Plus it'll be there when you do get faster.

 

[six is enough]

Back in 1997 Kenne Bell wrote an article on power adders. With a stock motor heads and injectors. Motor started out with 200 rwhp add chip 31hp 14 hp with full exhaust 13hp with ram air kit. dual stage header were worth 29hp.He then added a Big Boy front mount intercooler and was up to 307hp at the rear wheels. The next step was adding a 70mm Throttle Body this add on brought the rwhp up to 332. He wrote a bigger throttle body will allow more air flow but won't the pressure loss mean a sacrifice in low-end torpue? Isn't turbo lag a bad enough penalty already? We found zero pressure loss throughout all these tests due to this throttle body,and the whole system would make a ton less power with out it. just putting on the throttle body brought up the boost by four pounds. Thought I would share this with you it is only what was written for Popular Hot Rodding in October 1997.

 

[john evans]

my car mph's 121,t63e turbo w/9"non lock conv.i currently have a 62 mm t/body with an rjc power plate.the car is basically finished,but everybody knows that never really happens.thanks for all your input. :biggrin:

 

[DonnieShort]

my car mph's 121,t63e turbo w/9"non lock conv.i currently have a 62 mm t/body with an rjc power plate.the car is basically finished,but everybody knows that never really happens.thanks for all your input. :biggrin:

Looks like you are far from stock , I'd get a PTE upper and 70mm for it and never think twice.

 

[soundguy]

I upped mine to RJC's 70mm TB and plenum. Ya can see rest of car in sig. I can't tell ya low end difference, but on the highway, it kicks soooo much harder when you hit it. Also went from a max of 15 psi with the boost control at min to a max of 18 just adding those 2.

 

[441120]

70mm

Just my $0.02. I followed the Popular Hotrodding/Kenne Bell recipe starting in 1987 then continuing when the article came out in 1997. Every mod worked just like they said, 4 lb jump in boost just like they said with the 70mm. I just turned down the boost back to the original 17 psi ( at the time).
I later had some tuning issues that drove me nuts . While attempting to diagnose the problem I swapped the stock TB back on in place of the 70mm and during the "road test" power was down and so was the throttle response.
Like the others said save the throttle body for a later mod.
HTH

 

[ESP Products]

The GM High tech Performance article with ESP Products did not show an improvement with the 70 mm T-Body. We were not connected to that portion of the article, but the editor at the time told us that they were not pleased with the results. He said they gained 2-3 HP here and lost 2-3 HP there; they then changed their attention from the throttlebody to our fuel upgrades. The throttlebody was mentioned in the article more as a sidebar than a feature. The engine used was mildly modified. We, ESP Products, have never pushed the 65 & 70 mm throttlebodies. Dollar for dollar you can spend the money better elsewhere. Most street cars, 12-11 second range, would gain power, and save money, with a 62 mm upgrade and a plenum spacer or power plate. We have had more positive reports with 62mm upgrades than 65 or 70 mm upgrades.

Hope this helps.

 

[Jerryl]

The GM High tech Performance article with ESP Products did not show an improvement with the 70 mm T-Body. We were not connected to that portion of the article, but the editor at the time told us that they were not pleased with the results. He said they gained 2-3 HP here and lost 2-3 HP there; they then changed their attention from the throttlebody to our fuel upgrades. The throttlebody was mentioned in the article more as a sidebar than a feature. The engine used was mildly modified. We, ESP Products, have never pushed the 65 & 70 mm throttlebodies. Dollar for dollar you can spend the money better elsewhere. Most street cars, 12-11 second range, would gain power, and save money, with a 62 mm upgrade and a plenum spacer or power plate. We have had more positive reports with 62mm upgrades than 65 or 70 mm upgrades.

Hope this helps.

I applaud you and your organization on your honesty and feedback!

 

[DonnieShort]

The GM High tech Performance article with ESP Products did not show an improvement with the 70 mm T-Body. We were not connected to that portion of the article, but the editor at the time told us that they were not pleased with the results. He said they gained 2-3 HP here and lost 2-3 HP there; they then changed their attention from the throttlebody to our fuel upgrades. The throttlebody was mentioned in the article more as a sidebar than a feature. The engine used was mildly modified. We, ESP Products, have never pushed the 65 & 70 mm throttlebodies. Dollar for dollar you can spend the money better elsewhere. Most street cars, 12-11 second range, would gain power, and save money, with a 62 mm upgrade and a plenum spacer or power plate. We have had more positive reports with 62mm upgrades than 65 or 70 mm upgrades.

Hope this helps.

I too applaude you for your honesty. But on a faster car I can see where going bigger will help, but I'm talking mid 10's or faster.

 

[VadersV6]

Way I see it, the up-pipe measures 63.5mm or so...why not compliment it with a 62mm TB? It doesnt benefit anyone or anything to have a pinch right there at the TB, so why not make it all a smooth transition? That makes about as much sense as running a 3" DP and then finishing it off with a single 2 1/2" tailpipe.