65mm Throttle body performance

modular46

Member
I am finishing putting together my combination for my 87 GN which includes Precision 62-62 @ 25 psi, PT stock location IC, PTC 10 inch converter, 3 inch downpipe, RJC intake plate, upgraded fuel system, and EEC GN blue box computer running on E85. I want the maximum amount of torque response on the street. Will a 65mm throttle body take away from the low end response? How much power would it gain with this type of setup? If I did the TB upgrade I would port match the opening on the plenum cover.
 

TIMINATOR

Active Member
I personally prefer a 65 or 70 along with a larger up pipe, and better design "doghouse". This slows the charge speed into the upper "doghouse", making the 90 degree transition into the runners more uniform. The RJC power plate addresses this issue very well, but if you look at the differences in the holes in the plates, you notice that the larger the "doghouse" and t body application, the less radical the hole distributation slots need to be. These plates work! But, they can't work exactly correct at all RPMs, due to the many combos of cams, heads, t bodies, air velocities at a given RPM, and other variables. The RJC plates I have installed have always been smoother at all RPMs, but "living" on a flowbench, I realize they have to be a compromise due to the varied air velocities seen at various RPMs. I feel that the less you need to "adjust" the flow, the more balanced the air into the runners becomes at all RPMs. The injectors provide the same fuel flow to all cylinders, a cylinder with more air is leaner, and more detonation prone, regardless of the RPM. Detonation is bad!
Most advise is good, but the best advise you can get, is from someone that uses and has finely tuned a very similar engine combo as yours.
Being able to close your hood has caused he most grief in turbo V-6 Buick intake design IMHO.
TIMINATOR
 

Mr.Spool

Well-Known Member
I am finishing putting together my combination for my 87 GN which includes Precision 62-62 @ 25 psi, PT stock location IC, PTC 10 inch converter, 3 inch downpipe, RJC intake plate, upgraded fuel system, and EEC GN blue box computer running on E85. I want the maximum amount of torque response on the street. Will a 65mm throttle body take away from the low end response? How much power would it gain with this type of setup? If I did the TB upgrade I would port match the opening on the plenum cover.
You will see 0 gains with a bigger throttle body on 25psi with a stock motor and that turbo.
Tuning the motor suspension good tires,driving the car right,etc will net the best gains.
 

TIMINATOR

Active Member
Agreed, Mr.Spool, it doesnt make any difference how much HP you make, if you cant hook it! And the stock GN suspension sucks!
But with convertor, he did say he has a PTC 10", I based my answer on what he said, and asked.
I DID MISS the thing about E 85. The deal is that the tuning window is much bigger than on gas, and a bit of over fueling will lessen or eliminate a lot of detonation.
But I have run all of my blower cars, bikes, and boats (12 so far, or was it 13?) on pump gas or occasionally with a splash of AV-gas on top of it. So I really am more concerned with mixture distribution, than you alcoholics!
As a long time friend, fuel funny car and dragster racer, Ted Hoover put it: "if the happy mixture window with nitro is a dinner plate, alcohol is a saucer, and gasoline is a quarter. Ya wanna go fast on gas, buy extra rings and pistons!"

My flow bench shows better distribution, with or without a plate, with a bigger up pipe and throttlebody.
Also, I am in Phoenix,AZ. That means 115 degrees and about 5% humidity in the summer. I like to drive my car in the summer.

Also: "gasoline is for cleaning parts, alcohol is fer drinkin', and nitro is fer racin'"
R.I.P. Ted
TIMINATOR
 
Last edited:

Mr.Spool

Well-Known Member
Agreed, Mr.Spool, it doesnt make any difference how much HP you make, if you cant hook it! And the stock GN suspension sucks!
But with convertor, he did say he has a PTC 10", I based my answer on what he said, and asked.
I DID MISS the thing about E 85. The deal is that the tuning window is much bigger than on gas, and a bit of over fueling will lessen or eliminate a lot of detonation.
But I have run all of my blower cars, bikes, and boats (12 so far, or was it 13?) on pump gas or occasionally with a splash of AV-gas on top of it. So I really am more concerned with mixture distribution, than you alcoholics!
As a long time friend, fuel funny car and dragster racer, Ted Hoover put it: "if the happy mixture window with nitro is a dinner plate, alcohol is a saucer, and gasoline is a quarter. Ya wanna go fast on gas, buy extra rings and pistons!"

My flow bench shows better distribution, with or without a plate, with a bigger up pipe and throttlebody.
Also, I am in Phoenix,AZ. That means 115 degrees and about 5% humidity in the summer. I like to drive my car in the summer.

Also: "gasoline is for cleaning parts, alcohol is fer drinkin', and nitro is fer racin'"
R.I.P. Ted
TIMINATOR
The rjc plate seems to even out the air the cylinders for sure.
All the plugs I've seen has showed that😉
The ptc 9.5 is a night and day difference vs their 10.5 on a 200r4.
It's like a race car racing a stock minivan😎
 

Mr.Spool

Well-Known Member
Agreed, Mr.Spool, it doesnt make any difference how much HP you make, if you cant hook it! And the stock GN suspension sucks!
But with convertor, he did say he has a PTC 10", I based my answer on what he said, and asked.
I DID MISS the thing about E 85. The deal is that the tuning window is much bigger than on gas, and a bit of over fueling will lessen or eliminate a lot of detonation.
But I have run all of my blower cars, bikes, and boats (12 so far, or was it 13?) on pump gas or occasionally with a splash of AV-gas on top of it. So I really am more concerned with mixture distribution, than you alcoholics!
As a long time friend, fuel funny car and dragster racer, Ted Hoover put it: "if the happy mixture window with nitro is a dinner plate, alcohol is a saucer, and gasoline is a quarter. Ya wanna go fast on gas, buy extra rings and pistons!"

My flow bench shows better distribution, with or without a plate, with a bigger up pipe and throttlebody.
Also, I am in Phoenix,AZ. That means 115 degrees and about 5% humidity in the summer. I like to drive my car in the summer.

Also: "gasoline is for cleaning parts, alcohol is fer drinkin', and nitro is fer racin'"
R.I.P. Ted
TIMINATOR
I like my nitro with my alcohol 😉
 

TIMINATOR

Active Member
Again, what stalls are those?
We have no dragstrips here anymore, and street racing gets your car impounded. Its a FELONY!
So mine is a cruisin, mountain, high altitude car, all I need is good gas mileage and a strong mid range, with a killer top end from the turbo.
I know my convertor would be a turd at the track though, so I am trying to make as much torque as possible on the motor for regular street driving.
I don't want to bother the PTC guys, cause the motors not even assembled, so I dont know what I have yet. Only theory...
TIMINATOR
 

TIMINATOR

Active Member
The only problem with the plate, as I can see, is they are "tuned" for wide open throttle. Thats great on the dragstrip, but then again, differing combos will have differing airflow characteristics with differing heads, cams, etc. at wide open throttle. BUT, its the best thing we currently have!
When time permits, I will get back to my flowbench to continue research on my hush, hush, way cool street/ strip manifold.
All I want is balanced flow before and during boost, more bottom end torque, at a wide range of RPMs, and being able to close my hood.
As Z Z Top said: I aint askin fer much, woohoo!
TIMINATOR
 

Grumpy

Thread killer
The only problem with the plate, as I can see, is they are "tuned" for wide open throttle.
TIMINATOR

tuning is easier with the plate. we took it off an had to do each cly. Never had any drivablity problems. Drive a lot of them on the street.
 

Mr.Spool

Well-Known Member
Again, what stalls are those?
We have no dragstrips here anymore, and street racing gets your car impounded. Its a FELONY!
So mine is a cruisin, mountain, high altitude car, all I need is good gas mileage and a strong mid range, with a killer top end from the turbo.
I know my convertor would be a turd at the track though, so I am trying to make as much torque as possible on the motor for regular street driving.
I don't want to bother the PTC guys, cause the motors not even assembled, so I dont know what I have yet. Only theory...
TIMINATOR
Initial or flash stall?
It would depend on combo but usually initial stall would be 3200 with seeing boost.
 

TIMINATOR

Active Member
Initial or flash stall?
It would depend on combo but usually initial stall would be 3200 with seeing boost.
With the 9.5 or 10.5? How are the street manners? That is ALL I will ever do with this car! If I can footbrake stall(I have a 9" with big brakes) to 2700 or so, and have 4 or 6 lbs boost on the launch, and have 12 to 15 lbs across the intersection, I would be happy!
I have run an original 1972 Gran Torino Sport with the 351Cleveland that had a factory 3000 stall that wouldnt move the car till 2100+, and later stuff where a 3800 didnt seem too much looser than stock till you punched it. I would like something a bit looser than stock, but with a lockup since it will be a touring car. Art Carr and I have known each other and raced together for 40 years, so he did my trans and convertor. I havent assembled the motor yet, so I dont know what it will do, but all on here say it wont work well. Im exploring options in the next few weeks until it runs. I have a shop, lift, trans jack, and everything else I need, so I will try it first. Just getting info on whats out there now. TIMINATOR
 

Mr.Spool

Well-Known Member
With the 9.5 or 10.5? How are the street manners? That is ALL I will ever do with this car! If I can footbrake stall(I have a 9" with big brakes) to 2700 or so, and have 4 or 6 lbs boost on the launch, and have 12 to 15 lbs across the intersection, I would be happy!
I have run an original 1972 Gran Torino Sport with the 351Cleveland that had a factory 3000 stall that wouldnt move the car till 2100+, and later stuff where a 3800 didnt seem too much looser than stock till you punched it. I would like something a bit looser than stock, but with a lockup since it will be a touring car. Art Carr and I have known each other and raced together for 40 years, so he did my trans and convertor. I havent assembled the motor yet, so I dont know what it will do, but all on here say it wont work well. Im exploring options in the next few weeks until it runs. I have a shop, lift, trans jack, and everything else I need, so I will try it first. Just getting info on whats out there now. TIMINATOR
We run alot of ptc 9.5s up here.
They drive great for a nl, loose down low and couples up top really hard.
Drivability was within 50rpm of the lockup converter it replaced at cruise speed.but.. we all hit our stuff with power,and all of us have gone faster with the ptc.
I havent ran the ptc in mild buick stuff so I dont know for sure if performance will be above the other converters but on the stronger combos ptc seems to shine and I've seen alot of them in buicks and other platforms.
Dave husek has really good converters that I've seen do very well in the milder stuff as well as some stronger running cars.
If your tight with art I understand.
Not sure what he has going with his stuff.
Custom stators and getting the right degree fin angles is the focus of the newer stuff and has helped the cars spool better and not blow through the converters.
 

Mr.Spool

Well-Known Member
The only problem with the plate, as I can see, is they are "tuned" for wide open throttle. Thats great on the dragstrip, but then again, differing combos will have differing airflow characteristics with differing heads, cams, etc. at wide open throttle. BUT, its the best thing we currently have!
When time permits, I will get back to my flowbench to continue research on my hush, hush, way cool street/ strip manifold.
All I want is balanced flow before and during boost, more bottom end torque, at a wide range of RPMs, and being able to close my hood.
As Z Z Top said: I aint askin fer much, woohoo!
TIMINATOR
Haven't had any tuning issues with the plate at all regardless of the rpm.
Havent seen any need in the fuel enrichment area either.
 

SCOOBY DOO

I'M NOT A MONSTER, I'M JUST AHEAD OF THE CURVE!!!
I ran Arts 16930 with my 6262JB. It was tight on Erics default settings...you could get out and run faster. Dropping the low gear 02's to 770's and adding 6-8 degrees low gear timing it was a whole different convertor. Spooled instantly and hit full boost instantly. This was with Erics 110-112 race chip. I didn't race on the street so a tight convertor is my preference for DD and cruising.
 

Mr.Spool

Well-Known Member
I ran Arts 16930 with my 6262JB. It was tight on Erics default settings...you could get out and run faster. Dropping the low gear 02's to 770's and adding 6-8 degrees low gear timing it was a whole different convertor. Spooled instantly and hit full boost instantly. This was with Erics 110-112 race chip. I didn't race on the street so a tight convertor is my preference for DD and cruising.
Interesting
Back in the day on the small turbo stuff and stockish motor bolt on combos we ran ac 16930s but stalls were 35/3600 with race gas and high timing.
It was needed to get the cars to 60ft in the low 1.4 range on 58mm turbos and slicks, and 330 and they were more track setups inmo.
The converters worked good through the 1/8 mile.
 
Top