A better mod than Cams/Gears/ReFlash/AEM?

 

Not INSTEAD of.. IN ADDITION to.. This is the kind of mod that will improve the mods you've already made..

 

I have Cams, Gears, Piggyback and Dumpback exhaust. That's given me 100+ WHP (DD dyno) over stock. I find it hard to believe that a TB (throttle body) will give me the same level of gains...

I'd love to be proven wrong though. I have my money on the 10.5 housing swap, but should I put my money toward a TB instead? It's about the same amout of money...

-CJ

 

your asking too much from one mod... i believe other than tuning... cams, stroker kit, and turbo are the best mods...

what type of butterfly flap do you use if i was gonna port my stock TB to 63mm?

 

Nah, the Throttlebody is one of those mods that helps other mods work better.. The gains in and of itself aren't all that large.. In concert they can be decent.. If your weighing the gains between two items the TB and the 10.5 housing, the 10.5 housing will offer slightly better gains, but doing both will obviously be best.

Just a TB is not worth anywhere near 100hp gain, but you already knew that.. depending on other mods the HP gains can be as large as 15hp or more.. But on an otherwise stock car, the gains are not going to be very large (4-5hp if that much) Simply because there's other restrictions that need to be addressed before the throttlebody itself will be the restriction in your induction system.

Given the two mods, and if your prioritetizing them, I would definitely do the 10.5 housing first.. However once you do intercooler, pipes, etc.. then the next step would be the TB, then later would be restrictions such as the intake manifold, ports on the heads, valve size, etc..

What is interesting is after you do all the basic bolt-ons, costs go up and returns (gains in HP) goes down, thats why its so important to address all the restrictions and inefficiencies as possible since they are basically where your going to find those last bits of power.

 

I guess that's why I had to pipe in when CoolGuy posted that it was one of the best mods that his buddy's have done. I'd think that the mods that I've done would yield better gains. Again with all this stuff, every little bit adds up... I just wanted clarification on the prioritization...

 

I'd like to know the answers to these questions...

 

A larger throttle body can give the impression of more power at part throttle simply because it allows more air through at a given throttle angle. This can create the illusion that the engine is more 'peppy' (an old Subaru and Honda trick), and fool one's 'butt dyno', which is inaccurate anyway. Of course, unless the factory TB creates a significant pressure drop at WOT, there will be little or no increase in WOT power.

At this time, neither sellers nor any individuals can come forth with a properly conducted dyno test that substantiates any claims. This being the case, I'll remain dubious as to the benefits of a larger TB unless someone can come clean with a quality test that demonstrates otherwise.

In the meantime, I'll relegate this part with the likes of aftermarket intakes, larger IC and such, which have proven to be non-issues (or even detrimental) where reaching the power limits of the factory turbo are desired. With cars running 11sec E.T.'s with factory air boxes, IC's and TBs, money can be better spent elsewhere in the powertrain.

There are at least 1000 ways to throw money at these cars, and at least 900 of them amount to nothing more than exercises in financial depletion and 'bling'.

 

Ted -
You are The Man! It's good to have at least a few scientists on board here. No testing results, no money from me.

Rob S.

 

Empiricism is an important part of science but science is not empiricism alone. Figuring out how to ask questions and figuring out how to measure and what to measure is at least as important.

The great Empirical Dyno God does not always give the answer that one is looking for. For instance old straight six Jaguar engines as installed in C, D and E-types if any of you are old enough to remember these make more power on the dyno with SU carburators but they run faster lap times with Webers, which is why in fact the factory always fitted their hot race engines with Webers. The reason has to do with the accelerator pumps in the Weber and the lack of them in the SU. This affected transient throttle response suffciently to make up for the small but signifcant power advantage of the SU on a road circuit.

Anyway, rather than bashing people who obviously have thought about what they are doing (I include Buschur, Vishnu and Works among those), it makes for interesting questions on how they arrive at somewhat different solutions to increasing performance.

The fact that Vishnu runs a stock airbox that is likely to draw cooler air and uses copious fans while on the dyno may potentially account for the relative lack of performance gains with a FMIC. In contrast Buschur uses an open element and at least by what has been posted on this board seems to eschew the use of fans in the dyno room. Now, which testing procedure more closely resembles being stuck in California traffic on a hot summer day is also an empirical one.

Smoothing airflow can sometimes have amazing results on horsepower whereas sometimes there does not seem to be much of an effect. However, in my experience conscientiously and properly done port work and efforts to maximize airflow will always increase subjective drivability of an engine (I have done this on every single gasoline powered conveyance I have owned since day 1) and in combination with the right bolt-ons will always increase power over the bolt-ons alone.

Whether it is cost effective for you is another question. If you enjoy superb drivability of a tuned engine it probably is. If you are after the highest horsepower on the dyno and the fastest ET on the dragstrip, there are probably cheaper venues to get there.

And yes, a bored-out throttle body should change the tuning requirements somewhat. On Subarus people actually have empircally derived values for MAF scaling with bigger throttle bodies - there is an intersting thread on this on nasioc.com.

 

Seems like a good machine shop could do this no problem, but where would you get the oversized butterfly from?

 

A machine shop could probably just build one out of sheet metal. Just make sure they size and clearance the bore and throttle plate to account for thermal expansion. Otherwise, you might encounter sticky throttle or idle problems when your engine is warmed up.

The advantage of getting one from a shop that's built a few before is that they've done all the R&D necessary to make this plug and play. They'll know the proper dimensions and tolerances. Boring out a throttle body does require some precision machining to get right. If you go the cheaper route, you'll have to do your own troubleshooting and possibly reworking if something's not right. The last thing you want happening is your throttle plate being stuck open at WOT (don't ask me how I know this)!

 

Wow, someone with clarity. You deserve one of these:

 

Very well said...Their are too many Dyno freaks on these boards. For every mod they want a dyno sheet to proove to them that the mod in question is worth upgrading to.

 

Why shouldn't the effects of a TB upgrade be seen on a dyno? If Xhp gains are claimed, this should translate to a dyno in some form, right?

IC testing, due to the issues mentioned earlier in this thread, isn't so easy. However, my friends at PVO/Dodge are actually trying to address this issue with SAE by standardizing the dyno conditions to account for intercooler efficiencies-- something that has yet to be done, AFAIK.

Shiv