vac or dinan throttle bodies?

[Obioban]

If this becomes m3post, I quit the internet.

[Sharocks]

I have Dinan ITB's on both of my cars.

The NA one has the ITB's port matched "more" to the head when I built it.

The S3R is as is comes.

I noticed nothing but when I drive a car without them I can tell LOL

Just kidding I can't, but it's a lot of money for not a lot of gain. I'd recommend other modifications before them unless you're running out of things to do.

[9kracing]

I wonder if it would be worth reaching out to Kinsler. I heard they have made some one-off kits for race cars.

Obviously your average CSL-intake car isn't going to see any significant gains, but Sharocks and I might. Same with those stroker motors Chris is building.

I've seen a built Honda pick up 45 whp over a plenum when switching to Kinslers. Granted, this was a 13:1 car with big ol' cams, a custom header, etc... but I have no doubt our ITBs are sized for midrange and throttle response, not peak power. Besides, that Honda gained power throughout the RPM range, not just after 5K or something.



There is almost definitely power left on the table for serious builds. Our factory ports are 50mm. I believe Dinan ports them out to 52. I'd like to see a true custom set with 55mm+ throttle bodies and targeted runner length.

[Chrisyphus]

There is almost definitely power left on the table for serious builds. Our factory ports are 50mm. I believe Dinan ports them out to 52. I'd like to see a true custom set with 55mm+ throttle bodies and targeted runner length.

There’s definitely meat on the bones, as you said- you need to tailor the entire package to the application. Doing any one part is insufficient IMO.

[oceansize]

Yeah, honestly, the whole forum/street cred thing has been the bane of my existence.

You don't have to worry about this forum. I think overall you will find that the vast majority are pretty darn reasonable and detached. There are for sure a few and if needed I'll name them... 🤣

[Chrisyphus]

You don't have to worry about this forum. I think overall you will find that the vast majority are pretty darn reasonable and detached. There are for sure a few and if needed I'll name them... 🤣

No doubt- I have been thoroughly impressed with this forum so far! It has been an exceptionally warm welcome, and the discourse is high-quality!

[siamkazi]

Yeah, honestly, the whole forum/street cred thing has been the bane of my existence. Actually, 9K's post immediately after this is the perfect segue into this topic.



I'll answer your question in just a second, but first- Just Chris is fine 😁. To continue my response to Siam, the reason my username is Chrisyphus is that trying to debate the forum hive-mind is a less productive way to spend your day than Sisyphus pushing his boulder up the mountain lol.

It has legitimately been the bane of my existence, arguing for dozens of pages on M3post with people whose opinions amount to nothing more than support for whichever brand of parts they have bought for their car. I am not sure what the psychological basis of this phenomenon is, but it is insidious. People will spend hours of their day arguing with you on behalf of whatever brand they are loyal to, and for no reason more than it is what they spent their money on, and I guess, if you say there is a better option (or even one just as good), they react as if that is a direct indictment of their intelligence.

Finally, after years of engaging in these conversations, I have gained enough respect as a result of showing my work to the world, so it is finally getting easier to have these conversations without it getting turned into a pissing contest.



Back to the original topic- the dyno conversation.. I read a bit of that page and they were all arguing over which dynos are more accurate and the things that can make a difference. DynoJets aren't the industry standard because of clout or anything like that, they are the standard because the way they measure power is so simple. The drums are a known mass. They measure horsepower by the acceleration rate of that drum. That is it. The manufacturer calibrates the formula to the exact weight of that drum, and that is job done. It is just a simple drum built on a train axle. Atmospheric correction factors are based upon known standards, and the only way to fudge the result is to cheat the interpreted gear ratio (if you are not reading the RPM signal from the car) or to put a hot cup of coffee under the atmospheric sensor.

Having said that, my own car on our in-house 424-XLC has read more than 30 Hp different over the countless dyno pulls I have done. The only fair comparison is the same car, same day, same dyno. Anything else is comparing apples to oranges.

9K, you asked about what intake/exhaust differences we run for our strokers vs. stock displacement- at the moment, nothing. For our long block orders, we ship a long block with whichever accessories the customer requests. What they plumb them with is up to them, and sometimes they have us tune them, sometimes they have their preferred tuner. So far, for our in-house builds, the cars usually arrive with an aftermarket header and intake already installed. Unless otherwise requested, we reuse those in the build. At the very least, Peter recommends SSV1, then Epic (if you can find them, and even more unobtainium- Genuine BMW Motorsport headers. That said, I believe they are all suboptimal. Some of you may have seen that I am collaborating with Alec on an S54 header project, and we are learning a lot at the moment. There's a ton of work to do that I do not believe many non-OEM exhaust manufacturers are doing at the moment. What I know for sure is that the header options on the market are not optimal for a stroker engine, and we do intend to build profiles to allow us to rapidly and inexpensively (relatively speaking) manufacture headers bespoke to each engine build- tailored for displacement, cam profile, compression, and the end user's desired power curve. Eventually, I am sure we will be doing the same for intakes.

As far as throttle bodies and the heads themselves, this is why we invested in ANSYS's entire suite of simulation software- the price of this is obscene, but it is the only way to make educated decisions on geometry changes to optimise airflow. In addition to this, I am consulting with Darrin Morgan (Darrin is a legend in the drag racing community for his ability to optimise naturally aspirated racing engines- he is able to achieve greater than 140% VE in naturally aspirated engines) on how to optimise our exhaust and intake systems best.

For intakes, Turner's CSL rep box is a great value that breathes well enough, and if you want something that looks better, you cannot go wrong with Karbonius.

I am continuing to develop pulsatile flow profiles for intake and exhaust systems across all platforms we work with to ensure we can create the very best parts possible, but that takes time.

The header part is really exciting right now (following the other thread you guys are doing analysis in), so ideally it looks like there may be a better option header wise that compliments the stroker setup and the other serious builds here? (serious referring to those like 9k,sharocks, and others above)

[eXpensiveGears]

I really appreciate you saying this. Sometimes I feel like the time I spend on forums is wasted, but feedback like this reminds me the value of engaging in this way.

Thank you!

TRUST ME, IT IS NOT WASTED TIME. sorry for caps I was in high school when the E46 M3 was in production, and I didn't get to buy one until after I graduated from college and started working. I've had my car for almost 13 years now, 44k -> 105k miles on it. 2006 ZCP, BONE STOCK minus maintenance and tyres. I'm one of the older guys who appreciate time, attention, education and OBJECTIVE validation and opinion on what you're selling and what's possible. I'm currently looking into a "throw everything and the kitchen sink at" type of builds as your customer with the E39 and E46 has done and you would be my first call as soon as I'm ready to pull the trigger. Appreciate you taking the time and all that you do.