Well, I been driving the car for almost a week with the max bore T-body on to a stock intake manifold.

Why did I go with the max bore instead of the regular Works T-body?

The max bore's diameter is slightly bigger than the stock intake manifold,but hardly noticable. So the guys at Works was little worried since I'm just going to use the stock manifold which would create turbulance instead of smooth air flow into the manifold.
But, my theory is since the air will be forced into the manifold at 19psi no matter what, the turbulance will mean better air to fuel mixture creating better combustion (more torque) plus more air will be introduced by the bigger T-body. It sounds like it should work pretty good....more turbulance+ forced air = torque.....and....

All I can say is I'm very happy with the result. After having installed a 3in DP, 3in HF cat, 3in cat-back, lower ic piping, and intake with upper ic pipe, I felt some loss in low-end torque but better top-end power. With the max bore T-body, it seems all the loss torque is back but still maintaining the top-end power.
Now the car pulls hard once the boost kicks in. Hitting 60mph seems lot faster and easier from a roll. My guesstamation is that the max bore will cut about 2/10 of a second on the 1/4 mile. It feels so much better like it's a 2.4L driving on the street.

Issues: only issue that I have is the idle rpm seem to change from stop to stop. The idle is still smooth and doesn't fluctuate but it ranges from 850-950 at different stops. For instance, at one stop the idle comes down to 900 and stay there than at the next stop it might be 930 or drop to 850.
I'll drop by Works and have them check. Maybe it's normal for max bore to be this way.

Overall, I'll recommend the max bore to anyone with decent amount of performance parts.

 

Your idle is at 9000?? Mine's at like 870rpms.

 

I wrote this at 2am and added one too many zero.

 

LOL, its an S2000 9000 rpm is perfectly fine Im thinking of getting a throttle Body as well, but I might wait until I get the cams, hopefully I'll have the P2 in a few weeks.

 

LOL, well not idle at 9K...you know what I mean :P

 

I wonder if we can bore out the intake manifold inlet to port match it w/ the big bore throttle body.

This is what I did on my GSX.
http://www.roadraceengineering.com/2gtbswap.htm

I ported the intake manifold inlet while the manifold was still on the engine. I just stuffed paper towels in the plenum and was real careful not to get any metal shavings in the engine.

I'm not sure I'd want to do this on my EVO though. Hackjob mods like this seem a little ghetto for the EVO.

 

There's no reason why you couldn't do tons of good things to the stock intake manifold.. This is my plan.. Use the works big bore TB, match the intake manifold to it, have the entire intake manifold extrudehoned (more to smooth the interior surfaces and remove a little material) and then port-matched to the upgraded head..

Big HP gains.. I dunno.. worthwhile? Well, we've learned that little things in concert sometimes can have a bigger net affect than the individual modification is worth.. so for me and my intended combination its worthwhile, PLUS I like stuff that looks pretty stock.

 

It sounds good. I believe port matching and smoothing out the intake manifold should help gain pretty good HP and torque. I'll say if anyone raised the redline to 8K plus will benefit even more from bigger TB and modded intake manifold.

I'm just glad I got the Works max bore TB since it runs really good as is and in the future I still have rooms to improve the intake manifold for even better result.

 

The Works max bore TB really does work, I had to change the tune after install, so it is flowing more air, also my dyno(butt) says it works. Malibujack is on the right track for a killer street setup, I did the big bore TB and extrudehone on my daily driver Porsche 944 turbo and it made a huge differance in throttle response and power.

 

He's right. It will.


Not no matter what. What does matter is that every little bit of restriction to the air flow is a loss of efficiency. Why even ditch the stock throttle body for that matter? It's "at 19 psi no matter what," right?


...and you're applying the truth (turbulence = good things) to the wrong part of the engine. You want turbulence in the combustion chamber to stir the mixture for stability. You don't want turbulence in the induction system (pipes, hoses, or manifold) because it's an inefficient method of delivery. Books have been written on head work and porting because it it's significance. Not many books on using ill-fitted TB's to stir up some power.

The manifold's plenum should have ample supply of smoothly delivered air. It's all about the resonances of the intake ports pulling air from the plenum and having each intake charge get more turbulent downstream of the intake valve.

Turbulence equals the good things mentioned above, but not, by itself, power. You add the power with more air/fuel or timing.

Try a set of colder range plugs if you're searching for a benefit synonymous with what turbulence would provide.


The reason it feels more torquey on the street is just because you're giving it a much larger amount of air for the same throttle blade angle as before. For instance, crack a barn door and you get quite a bit of flow potential. Crack a tupperware lid and you won't.

I think there's a solid chance that things are more perception than reality. The extra air the bigger TB is moving with slight throttle inputs is the range of throttle you feel the most when driving around. You've more likely spent a great deal of time cruising at partial (yet powerful) throttle blade angles, so it would seem like the car is more powerful overall. Plus, it probably is as well, adding to the fun

The effect on your dome is a great thing. I did this (well, sorta) to my LS1 Camaro with LS1 Edit and it felt like I dropped a big block into the car. This is with no mechanical change to anything, just a revised throttle ramp rate in the PCM - point being that YOU now have a huge tangible/real shift in air delivery rates vs. what the computer thinks it should get based on throttle angle. The stock vs. Max Bore TB's are going to have two completely different flow curves if seen on a graph or table, which is what the ECU is basing it's calculations on.

Since it's also got a MAF, you'll probably be ok, but in tuning my supercharged mustang (also had a MAF), I realized that this little discrepency left the stock ECU lagging in accelerator pump fuel delivery and my car would go lean and detonate when I shifted. Needing the overall flow ability of the larger TB, I just turned up the fuel delivery parameter with the EEC-IV tuning software I had -- adjustability that you likely don't have for your Evo.

You may be leaning your engine out dangerously at moderate throttle angles (and boost), so you should at least check that somehow. Add some racegas and see if it helps power at partial throttle/boost. If it does, your knock sensor is probably going ape$hit on pump gas.



I would check to see if the blade isn't binding in the bore. Many TB's have bearings with sloppier thrust tolerances than are found in the bore/butterfly fit - leaving rubbing marks in the bore near the pivot points. If that's what's hanging the TB open a bit, use some 600 grit sandpaper on the area where it rubs to relieve it and smooth it out.


I hope the TB drops .2 (ill go buy one too) but it just seems unlikely as hell to me. Do you ever run the car at the strip?

Happy Thanksgiving

 

What is this a Works customer wanting to prove their power increase at the 1320. I surmise the area under the curve adage growing old. Go get that empiracal evidence that we have all been waiting for.

 

I'm sorry but I do not understand what you are trying to say???
Maybe this will help?

We suggest placing three pressure transducers 120 deg. apart from each other at the mouth of the throttle body and place three more in the intake manifold right after the throttle body. Then measure how much the pressure differential decreases from stock to the WORKS Apertures.

For gathering precise data on this product, we highly suggest using an engine dyno as opposed to a chassis dyno.

 

I have to agree with some of what’s been said here, while you’re feeling some improvement, it’s not an efficient one and it’s not all the mod can deliver given the conditions its working under. Mis-matched intake components have the same problems as mis-matched exhaust components, just the way it is, no excuses.


SCCA SFR Fresno Chapter
#33 SM
2004 Fresno Chapter ESP Champs

 

My final review after driving it and testing it on the the streets for weeks.
-It feels good at part throttle daily driving (feels like more torque).
-At full throttle, it pulls harder than before. For instance, in the past I am able to hit 70mph (stock speedometer maybe off by -2mph) within a block and come to a stop with max braking but now I have bit more room to stop with ease.
-There is a place in the park that I use to test my car to see how fast I could shift and go (rolling start). Before I would hit 90-95mph but now I reached close to 100mph. I'm shifting through the gears little faster too and I shift very fast. The other day a STI passed me at about 100+mph while I was doing 80-85 . I went to 4th and punched it and made up about 3 car length doing 140+mph in about 3/4 of mile (it seems after 140 Evo's have hard time climbing).

But the purpose of this review is for those who are planning on the Works TB. Should you get the regular TB or the Max bore TB. Well, even though the max bore TB is not matched bore to the stock intake manifold but slightly bigger (not much really), it works very well with the mods I have and you can match bore the intake manifold or get an after market one in the future without worrying about the TB being too small.

My theory on dyno. Most people who have dyno'ed TB or even intake have not seen real power gains on a dyno while other parts do make power. Why? cause dyno is not real world driving. It is very difficult to re-create the air that goes through your car at 60mph and above. And anything that has to do with the intake side are affected by air. Hence no one says intake gave them low-end power but high-end seemed to improve. I have an Injen intake and I know this thing makes power. Some dyno claims no or little power gain while Injen dyno claims 10+whp (I wonder who has a better fan). My friend who also has the Injen kit swears it made his car faster (it could be all in our head but I highly doubt it). Others who have installed the Works TB swears it makes more power but last dyno that I heard off didn't see much power gain compare to stock TB.

Overall

Works TB (Max bore)
Price is little too high but I installed it myself with Works tools and some help from Jamie and Tyler saving me the install cost.

 

How much is the max bore tb? I only see the original one on the website.