Disclaimer: This Thread is based off of my observations, experience, and logic only, so PLEASE do not comment or post if you disagree with any of them. You have the right to think whatever you want... just please don't clog my thread with forum BS. This is an account of my experience, and I have no interest in arguing with ANYONE about any different ideas, experience, or theories that you may or may not have. I also in no way intend to promote or bash BMW, DINAN, or Riot Racing. I'm simply showing their products as they are and explaining my personal experience with them.
OK Guys-
I was looking for something new for my e36 (since I'm addicted to modding it
) and spent some time looking for a thread about BBTB's and the differences between the options that are available. What I wanted was some reviews from people who had personal experience with them, and a rundown about their real-world performance - so I could determine if it was something I would be interested in, and further, if it was "worth it". I was particularly looking at comparisons between BBTB's, since I already have a Dinan BBTB and thought about upgrading to Riot Racing's BBTB.
I was less than satisfied with what I found (on bimmerforums or ANY other forum for that matter)... mostly people flaming, being flamed, or arguing about theoretical nonsense and whether or not it "does anything".
So I decided to make this thread for any serious E36 owners who want a new mod and aren't sure about the BBTB... since I own and have used all 3.
The logic behind the Big-Bore Throttle Body:
The E36 Throttle body is a modest 63.83mm (internal) bore from the factory, while the intake manifold has a 70mm opening that it mates up to. This means that the TB is not set up to flow as much air as it could...which inspired companies like Dinan, Riot Racing, and VAC Motorsports to develop a bored out throttle body which would allow more air to pass through the throttle body at WOT, thus reducing the resistance and increasing throttle response and peak horsepower.
Since the engine is essentially a big air pump, as we know, increasing the flow of air and reducing resistance in the intake tract will usually increase our overall horsepower. This is why mods like the M50 manifold, Samco intake boot, ASC Throttle body delete, 3.5" HFM, and Cold Air Intakes are commonly seen on e36's in an effort to squeeze out every last bit of power from our S52's. It can be broken down simply... Larger tubing, larger intake runners, smoother curves = less resistance, more power.
It just makes sense to me that there would be an increase in power from adding a BBTB, since the whole idea of most of the NA Mods is to lower the restriction of the 3" intake system. I've heard many people argue that the 3.5" intake setup is totally unnecessary for an NA M3. I've also heard that the TB is "not the bottleneck". However, If you believe that the 3.5" HFM, 3.5" CAI, or samco boot does anything, then you have to believe that this will too because it operates off of the exact same principle. The 3.5" Intake is 88.9mm inner diameter (3.5"), which smoothly shrinks down to 76.2mm (3") in the Bimmerworld boot, then goes through a throttle body which has a 63.83mm (2.51") inner diameter? Sounds like a bottleneck to me... Even at 68mm, the TB is still the smallest inner diameter in the intake tract!
Note: Dinan, Jim Conforti, and Active Autowerke all must believe that the 3.5" HFM makes a difference... since they all make a tune specifically for it AND recognize the power gains it yields.
The last thing to consider is throttle response. The idea here is that being a larger bore, at the same throttle position the BBTB will pass more air. This means that when you're at 25% throttle, the different throttle bodies will each pass different amounts of air and cause the engine to accelerate more or less. This GREATLY effects the way the throttle feels in the e36, there is no 2 ways about it. The BBTB pulls your neck harder when you hit the gas and makes the car seem to accelerate much more effortlessly at low-mid throttle. Throttle response is mostly based on feeling, though, so this cannot really be described. Drive an e36 with a BBTB and you will understand.
So, back to the point. I started with the OEM throttle body (like the rest of you), upgraded to the Dinan BBTB (because I got it for free from a friend who totaled his e36) and I loved it. I also have Dinan stage V software, which apparently is designed to work with their BBTB (although you do not need software to run either the Dinan or Riot Racing BBTB). Last week, I upgraded to the Riot Racing BBTB, and WOW... I cannot describe my level of satisfaction. It blows the Dinan BBTB away and in my opinion, is worth every penny. But I'll get to that later. So, I have owned all 3 and used all 3 personally on my car.
Now for the comparison:
Here are a couple of pictures of the TB's next to each other.
Now I'll separate them. It will be Description first, then pictures.
Stock TB:
Inner Diameter = 63.83mm
Throttle Arm: Double Sided
THINGS TO NOTICE: The OEM throttle body has an uneven bore... wider in the center than in the rest. This is restrictive and is not smooth.
Pictures of the Stock throttle body:
Dinan BBTB:
Inner Diameter = 66mm
Throttle Arm: Double Sided (OEM Style)
Area compared to Stock: + 6.46%
Price: $300 + $350 Core Deposit (ouch) + Tax + Shipping
THINGS TO NOTICE:
The Dinan throttle body appears to have been bored at a strange angle... if you look you can see that only one side of the inside of the TB appears to not have been changed at all.
The Dinan throttle body (on the manifold side) has a very thin inner wall... much thinner than any of the outer edges of the RIOT or OEM TB's. This has to do with the angle that it was bored at. It's uneven and looks very close to the breaking point of the walls of the TB, but has held up just fine.
Pictures of the Dinan Big-Bore Throttle Body:
Riot Racing BBTB:
Inner Diameter = 68mm
Throttle Arm: Single Sided
Area compared to Stock: +11.90% (+ X% because of low profile throttle plate and Single Sided throttle arm)
Cost: $250 + $100 Core Deposit (About $287 when it's all said and done if you live in CA. If you don't, lucky you, it's about $267)
THINGS TO NOTICE: This is the only throttle body with a smooth path all the way through. Notice that this TB was bored straight and that there is only 1 inner diameter that is held consistently.
Also, notice that there is a single sided throttle arm.
Pictures of the Riot Racing Big-Bore Throttle Body:
What the Inside looks like: Smoothness + Single/Dual Throttle Arm design
The OEM and DINAN throttle bodies have double-sided throttle arms, and the RIOT RACING unit has a single throttle arm. This alone frees up quite a bit of area. Also the entire inner diameter is consistent on the Riot Racing TB, unlike the OEM and DINAN TB's. See these pictures if you don't know what I mean:
And Lastly, The Big Question: POWER
I've been getting lots of people asking for dyno results. Well, I didn't dyno my car before/after and I've already gotten rid of my Dinan BBTB... so I apologize for anyone interested purely in power. There's NO question that the BBTB will add horsepower vs the stock one, and by the same principle, the Riot Racing one will beat out Dinan's. However, by how much I'm not sure. However, one thing I can say for sure is that the Riot Racing BBTB Feels much more refined than Dinan's and that it has absolutely no problems or downsides that I can find (plus, it's cheaper!).
However, for those of you interested in power numbers, Here's a few dyno charts that show the stock bbtb vs riot racing back to back.
Westcoastriots Dyno:
This dyno chart is from westcoastriots.com which I believe to be accurate, but some people speculate that it may be biased (since they sell the throttle body). This is NOT the only example. Their dyno page can be found here:
http://www.westcoastriots.com/htmlfiles/dynopage.htm
Eurotuner's Project Car Dyno:
This chart is from eurotuner's article which includes Riot Racing's BBTB. They did back to back dyno runs (with detailed methodology in the article) and found the BBTB to add 5.4 WHP. It's safe to assume that they had no reason to lie or fake their dyno results page.
Here's a quote from their article which can be found Here:
http://www.eurotuner.com/techarticle...g/viewall.html
This is a quote from the article:
"Next was the $200 big-bore throttle body from Riot Racing. With a 68mm port to perfectly match the inlet port of both the M50 and M52 intake manifolds, coupled with the thinner throttle plate, we were confident we'd see a gain.
On the dyno, the peak power went up to 236whp at 6700rpm. RR's claim of an 11% flow improvement was good for a fairly consistent 3-5hp gain from 4000rpm onwards, peaking at 5.4 at 6900rpm. We've had no adverse affects to throttle response or engine idle either."
This is their Dyno image. It's difficult to see though, because they dyno'd back to back after several mods.
OK, now a real-world review...
Stock: The TB is fine on the E36, but after doing the M50 manifold conversion, the throttle response seemed to go to hell. There's so much less torque in the 2000-4500rpm range that even daily driving, I felt like I had to constantly push the gas to 50%-75% to climb hills and accelerate without revving out (normal daily driving). Also, it doesn't make sense to have a hugely modified intake tract that bottlenecks at a 64mm opening.
Dinan: I loved this TB when I got it... it freshens up the pedal and you really notice it. It helped reverse the feeling of the loss of torque, but also made the car somewhat difficult to drive. When you BARELY touch the gas, the car seems to want to GO, then from 10-50% throttle, doesn't seem to have a linear response. Also, The idle was unstable (if I let it idle for a couple minutes, it would bog to 400rpm then back to 800 roughly every 30 seconds). Also, it made a very annoying (and embarrassing) whistle sound every time I crossed about 5% throttle (either when pushing on the gas or letting off, and would whistle for hours if I held it there). The pedal was very touchy, even after several adjustments of the throttle cable.
Riot Racing: The most impressive upgrade I have done in a while. I won't say anything about horsepower, although according to RR you're looking to get around 5-8whp out of it depending on the mods you have... and the Butt dyno Definitely agrees!! The car feels faster in the 4500-7000 range. I believe that logically, it HAS to add some power up top, since the smallest part of my intake system is now 12%+ larger than stock! But the biggest difference that the Riot Racing BBTB makes is the smoothness of it all. I felt like I lost a bit of the OEM feel of power when I did the m50 manifold, and the OEM refinement of the throttle control when I did the dinan BBTB, but with this one, I got back the OEM feeling of quality from the entire setup. It's easier to shift smoothly and can be driven gently and comfortably if you want to... but when I do hit the gas a little bit, it pulls me back in my seat WAY more than stock, and even noticeably more than the dinan BBTB, and inevitably adds a few horsepower. It's definitely a Win-Win!!
Seriously guys, I'm not a rep, I stand to gain nothing from making this thread. But this Riot Racing TB upgrade has made me so happy that I felt it necessary. I think that everyone who has an m50 manifold should buy one of these things... they REALLY make it feel better, more responsive, and faster. Also, the machining quality from Riot Racing is second to none, and their customer service is fantastic. The way my car sits now (see my sig for mod list) feels like it drives as smoothly and refined as a completely stock car. Plus, the effect of the better throttle response can be seen totally stock, m50 manifold, Cams, forced induction, etc. This thing can only help... no matter what mods you have already, or plan to do in the future. Plus, no software required!! That's a huge benefit on its own... it sometimes seems like there's never a perfect off-the-shelf tune meant for your exact setup.
Also, on a side note, Todd at westcoastriots was very helpful... he answered all my questions, and even allowed me to send in my throttle body ahead of time so I didn't have to pay the Core charge (those things always make me uncomfortable). They had it shipped incredibly fast, and from what I could see (and feel), they are obviously the best machinists who have ever tackled this job. Bravo, Riot Racing!!
PLEASE NOTE: This Thread is based off of my observations, experience, and logic only, so PLEASE do not comment or post if you disagree with any of them. You have the right to think whatever you want... just please don't clog my thread with forum BS. This is an account of my experience, and I have no interest in arguing with ANYONE about any different ideas, experience, or theories that you may or may not have. I also in no way intend to promote or bash BMW, DINAN, or Riot Racing. I'm simply showing their products as they are and explaining my personal experience with them.
Thanks for reading, I hope this helped somebody.
-Dave
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