3100 throttle body upgrade

[95Achieva]

Is a late 90's 3.4 throttle body bigger than the stock one on a 95 3100 ? If so, is it a direct bolt on (linkage, sensors, etc)? If it is not bigger or will not easily bolt on, which throttle bodies would be best to look for for a slight upgrade from stock. Nothing radical, motor will have maybe 200 hp in its final form.
Thanks for any and all info.

[korbendallas68]

Yes it's bigger. And to get 200 hp, your going to need something bigger than a 3400 TB (56mm)....

And it is a direct bolt on (sensors will work)... except for the linkage, and thats very easy to swap over... You are not going to see any performance gain from 4mm though.....

Shoot for a 62mm, matched to ported intake manifolds. **(The ONLY way a 62mm is really have any effect on your car is to match it to the right sized opening on the plenum, hence you need a ported intake....)

[Canada]

Yep, the neck of a 3400 intake manifold is still small....I believe we measured it either at 58 mm. Tiny. There isn't much material to port out either.

To swap over the linkages (you only need to do this if you have cruise and you want it to work.) is simple....

-Remove the two TB plate screws, I want to say T15.
-Slide out the plate.
-Remove the TPS, I believe thats also T15.
-Tap from the TPS side with a hammer, it'll break loose and slide out. Watch the throttle return spring, its killer.
-Reassemble with the 3400 housing and plate and 3100 shaft, remember the return spring. Doesn't matter which TPS or IAC you use, they both have the same part number.

From that swap alone, you might see a 2 hp gain a 3100, thats about it.....but it IS something cheap and easy to do. Realistically, porting your intake manifolds and heads at this point is worthless. The key area here is headers.....99+ 3400 Grand Ams make 18 hp with headers.

[customandsound]

i got one from a 95 3.4 sfi i want to put on a 3.1 how much work would that be ?i was going to swap out the whole top end from a 95 carmaro

[Rhedalert]

The key area here is headers.....99+ 3400 Grand Ams make 18 hp with headers.

I heard it was more like 30hp

[95Achieva]

Thanks for the info/replies guys.

From that swap alone, you might see a 2 hp gain a 3100, thats about it.....but it IS something cheap and easy to do. Realistically, porting your intake manifolds and heads at this point is worthless. The key area here is headers.....99+ 3400 Grand Ams make 18 hp with headers.

I was planning on some head work, a little grinding on the intake manifold, and a switch to higher ratio roller rockers. Why do you say massaging the heads and intake is worthless? Do you mean that these changes would not add much power since the motor is corked up by the restrictive exhaust manifolds?

Do 99+ 3400 Grand Ams come from the factory with headers? If so, would these headers bolt up to 95 to 99 3100 heads?r

[korbendallas68]

No they didn't come from the plant with headers. And yes and no about the 3100 heads... They will bolt up, but Brad's already tried on his Beretta to see if they fit, and it's a no go for room behine the engine... You WILL have to have a custom down pipe made (if you can can even find enough room!! It's a tight squeze as it is...)

[Cliff8928]

Yeah, that rear STOCK manifold off the 3400 is a tight squeeze at best, and that's with a 5-speed!



Yeah, i already know i can't weld that well, but it works for now..


Cliff Scott
89 BerettaGT
89 Volvo740

[Canada]

Here is Tim Wortman's dyno chart from BerettaFest...


He had a 3400 swapped into a Z26 with a 3.33 4T60-E.

His mods included....

-Cone filter on stock rubber inlet hose
-62 mm TB, I believe it was an APOC unit.
-Street Arsenal upper and lower intake manifolds
-Street Arsenal Stage 2 heads
-Fast Forward Performance UDP
-2.5" press bent exhaust

As you can see he made 157 whp.

Here is my chart from BFest...


I had a 3100 and 2.93 4T60-E with..

-RSM Racing's WAI
-Fast Forward Performance's UDP
-2.25" mandrel bent exhaust

I made 138 whp.

Now for some assumptions to make this a bit easier.

-I'm going to call the exhausts equal.....2.25" is the same as a 2.5" on a 3100 and press bent is less an ideal.
-Lets call the intake and cone filter the same....even though my RSM is worth a bit more.
-We have the same UDP.

Other than the 3400, Tim has Street Arsenal heads, intake manifolds, and a TB on me.

Depending on which stock rating you use for these motors, a 3400 has around 25 peak hp on a 3100. 155 and 180. This translates to 20 hp at the wheels assuming 80% loss (its more like 79%).

In theory, if I would of had a 3400 at the time, and my bolt-ons make the same gains to a 3100 as a 3400 I would of made 158 whp.

Now, I know this isn't exactly the most scientific piece of work....but it IS something to consider, beings no one has done a direct dyno comparison.

The Other Guys, aka TOG, (www.theotherguysproducts.com) made 18 wheel horsepower....there dyno chart.....



174 - 156 = 18.......thats an insane amount to gain from headers......V8 guys would KILL to gain that from headers alone.