How mych HP/TQ i lose for not having bigger Throttle body

[Slow5.0]

I think everyone here knows whats my mods ,but here is anyway http://img.photobucket.com/albums/v165/Seth5.0/Stang projects/Modifications.jpg

I still runing stock TB ,so i was thinkin whats my HP/TQ lose, i can pull 870 kg/hr (reading on TwEECer RT) so what you guys thinks about this

 

[94gts]

also i recently found out that if you want to make any kind of decent power you should stay away from chambered mufflers. which sucks for me cause i have flowmaster 40's and i like them

 

[Slow5.0]

also i recently found out that if you want to make any kind of decent power you should stay away from chambered mufflers. which sucks for me cause i have flowmaster 40's and i like them

Just like me, but difference in HP/TQ with mufflers is small (1-3HP) so mufflers are about sound

Now lets back to TB post

 

[wytstang]

IMO you will gain not lose. I prefer the FMS 65mm it will flow well for what you have and is best in quality.

 

[WhiteDevil]

syou are probably down about 8-10rwhp. I did the 298rwhp with my old FMS 65mm which the center shaft broke mind you. I went to a dyno day at the same dyno a few weeks later with my stock one and was down to 290rwhp. So its some where around there. With my new 75mm tbody and 75mm elbow i see 930kg/hr or so on my tweecer at 5,800rpm.

 

[Slow5.0]

IMO you will gain not lose. I prefer the FMS 65mm it will flow well for what you have and is best in quality.

I meant how much i missing ,so if i have 70 or 75mm what i could gain

 

[urban96]

good info white devil

 

[final5-0]

Ernan

I could not say for sure about how much gain a larger tb would give but it seems to me that the info John provided would be in the ball park.

As for the airflow in the data logs I'll be happy to share what I've seen in mine with you guys. My sig combo is now using a 65tb like Ernan's and a shorty ProM80 maf with a home made cai. I use an Edelbrock elbow btw.

I pulled two dl's from dialing in my af ratio that had some rpm's up high. I usually don't go any higher than 6200 but could not find any dl's with that rpm value.

dl 1 5800 928kg
6100 931kg

dl 2 5800 926kg
6100 931kg

That air flow value can be misleading due to how accurate (or inaccurate, lol) the high end of your maf curve is. The highest value I've seen from my combo was in the low 940 kg range. It was just after I put the 80maf on and it was too fat on the high end. After I got the curve more like it should be, the value came down, which was no surprise, lol.

Later
Grady

 

[Slow5.0]

final5-0 I don't have 65mm TB, i have stock 60mm ,and 870kg/hr i pull at 6000 in 4th gear on one run on HWY lol

 

[final5-0]

final5-0 I don't have 65mm TB, i have stock 60mm ,and 870kg/hr i pull at 6000 in 4th gear on one run on HWY lol

I do undersrand that you are using the stock tb.

Air flow is directly related to performance. More of it means more performance and I think most would agree with that.

Since you and John provided max air flow values for your combos I thought I'd also provide mine for comparison.

As for how much air flow relates to how much rwhp I just don't know. ProM used to have something like that on their site but I never took the time to research it.

Tell you what......Now that I think about it......I've got data of air flow just before the 65tb and just after it was put on cause I remember I wanted to see what difference the larger tb made in air flow. If I can find it I'll put it up for you shortly.

Again, what that additional air flow means in rwhp gain

Later
Grady

 

[final5-0]

OK Guys

First of all......Ernan, I think I've finally got my head straight about your tb now. You are using the stock tb at this time, lol.

I found that data. I did two data logs for each tb to make sure the data was consistent. Nothing but the tb was changed.

Stock 60mm tb
11-26-03
log#1800 5800rpm 778kg 12.43af
log#2158 5950rpm 780kg 12.46af

FRPP 65mm tb
11-29-03
log#1929 5850rpm 805kg 12.33af
log#2254 5950rpm 805kg 12.49af

That gain of 25kg of air flow has to mean a gain of performance but how much remains to be seen I guess.

Keep in mind that this little test is not necessarily accurate cause I was just about to or was pegging my stock maf at that time.

Anyway, for what its worth, there it is.

Later
Grady

 

[Touring23]

1.58 CFM/HP (theoretical)

 

[final5-0]

1.58 CFM/HP (theoretical)

So are we saying that if someone is smart enough to convert kg to cfm then that 25 extra kg of air flow in my little test could be converted into the hp gain of the larger tb?

Anybody know one of those guys who wears thick black rim glasses and always has one of those pocket protectors stuffed with pens & pencils?

Later
Grady

 

[5.0_GT_kid]

also i recently found out that if you want to make any kind of decent power you should stay away from chambered mufflers. which sucks for me cause i have flowmaster 40's and i like them

Why is that?

 

[95snoozer]

get a 70 man or 75 and fox Tb swap

 

[Slow5.0]

get a 70 man or 75 and fox Tb swap

What , i already have 94-95 Cobra intake and i spend 50+ hrs on polishing, and now you sayin get 93 Cobra upper because od that Fox setup

But I still tryin figure out 70mm vs 75mm

I wish we can test 60,65,70 and 75 on same N/A 302 car without any other changes, if anyone can get us some THrottle bodyes i would tested on dyno and find out whats true whats not

Or we can find somebody elses Stang and do it, we can all get together and put some money and buy Throttle bodyes from same company like BBK and tested and done with 65 vs 70 vs 75

What do you think guys

 

[95snoozer]

unfortunately that will never happen

just put a 70 on your cobra then.

i would look into having yoru cobra upper hone extruded ported cause of that neck which is a bottleneck and the amount your heads flow. definitely get a ported gt40 lower and work the neck of teh cobra when you do the TB swap.

75 mm tb on a 70 opening = nono

 

[Touring23]

So are we saying that if someone is smart enough to convert kg to cfm then that 25 extra kg of air flow in my little test could be converted into the hp gain of the larger tb?

Yup.

Anybody know one of those guys who wears thick black rim glasses and always has one of those pocket protectors stuffed with pens & pencils?

...and I like Star Trek, too.

 

[Slow5.0]

unfortunately that will never happen

just put a 70 on your cobra then.

i would look into having yoru cobra upper hone extruded ported cause of that neck which is a bottleneck and the amount your heads flow. definitely get a ported gt40 lower and work the neck of teh cobra when you do the TB swap.

75 mm tb on a 70 opening = nono

Last year when i got this Cobra upper and GT40 lover I polished and gasket mached ported little bit, and a few weeks ago i repolish upper intake and i open neck to 77mm so 75mm TB will be fine, i know i still need extruded honed but i did take a lot of casting first time so it flows much better than stock one
Here is a few pics when i did gasket matching, in time when i took pics i was half way to finish so ports are little wider than on pics http://www.cardomain.com/memberpage/358997/8

 

[Grn92LX]

Ernie, look at what Allmotor95 on here did. He has a stock bottom with TW heads, RPM II intake and a crower cam. He went from a small 65mm tb to a 80mm tb and gained close to 2mph at the track. 1.72mph to be exact According to internet racers, thats "too big of a tb", but hard to argue with REAL WORLD FACTS vs myths huh Break out the dremel and open up your cobra opening to 75mm and run a 75mm. You'll gain at least 1mph. I say you'll gain 8-12hp.