I keep thinking about twin turbos

[Damon in STL]

I get creative sometimes and then can't get something out of my head.

In the past I converted my M3 race car from an expensive s14 to a fairly inexpensive M42 turbo.







I have my 3.0 SC engine out of the car getting ready to install. I also have a spare T25 laying around and keep looking at it....and then the 3.0, and my mind starts thinking...





I keep looking at the above pics.....then at the one below.....

[krasuskyp]

NIKE! 8-)

and

lolz!!! Geoff - great to see you still lurkin amongst us idjutz!!! Don't wanna hijack the OP's thread so reply to one of the Dead Meat ones w/ whatchyou drivin these daze...

[xbmwguy]

You know what they say. If it’s got teets or a turbo it’s gonna give you problems
My turbo is running great but that thing with the teets is always a problem

[Damon in STL]

....playing with those melons WILL cost more in the long run....no doubt about it.


Back on topic.

The flow characteristics of each of the headers above look like they would be similar. Better than a log type but not as good as equal length with scavaging.

So, why have they not been used for a twin turbo setup?

[clutch-monkey]

with a modern single twin scroll would you not be better off dollars and performance wise?

[GJF]

If you stay below 800 a single will work fine. You want more than that? Then hands down twins. Faster spool below 800? Again twins. Today’s twin scroll turbos will spool fast, but to have instant spool and no lag at all.... twins. It’s more money but two well matched smaller turbos will almost always out perform a single. Very small pair of twins = super fast spool but suffer top end. Too big pair of twins = laggy but incredible top end. It all depends where you want the power to come in at and what you use the car for. A huge single will be laggy, and hit hard on top end. You just need to select the right combination for the way you want the power to come in. Also if you are going to make the jump to more power and twins, invest or fabricate a set of good tuned headers with proper wastegate ports. This alone will aide in additional spool characteristics and having well thought out wastegate ports ensures proper boost management.

[Tippy]

Here, I'll make it even harder on you....

You can pick up Holset HY35's off of Dodge Cummins trucks for some times only $100. 2 of them would peak around 900hp. The beauty of getting them from the Cummins, is they have had an easy life enduring only diesel EGT's.

I'm pretty sure those would light quick and deliver decent CFM for big power for peanuts.

[Bigtoe32067]

Holy High Octane Hooters Iceman! Those things are udderly ridiculous (with a Very Capital Dic)
For some reason I'm craving a cigarette and I don't even smoke.

What were we talking about?
Tony

[Damon in STL]

Originally Posted by Tippy

Here, I'll make it even harder on you....

You can pick up Holset HY35's off of Dodge Cummins trucks for some times only $100. 2 of them would peak around 900hp. The beauty of getting them from the Cummins, is they have had an easy life enduring only diesel EGT's.

I'm pretty sure those would light quick and deliver decent CFM for big power for peanuts.

Who pissed on your Wheaties?

[Damon in STL]

BTW....I'm not looking for big HP/TQ or necessarily cheap. What I am looking for is quick spooling at low RPM. Just enough to make the car a bit quicker.

I was hoping to get an appropriate accurate answer to my question regarding the use of the thermal reactor replacement pipes.

I raced with NASA for a couple of years and could not keep up with the big $$$ spenders. So, I've learned to get creative and use my brains and not necessarily my wallet. The link is to my build thread for my e30 M3 where there is an open rule set and HP:Weight classing.

I was hoping to get some type of accurate answers to my question regarding the use of the thermal reactor replacement pipes.

e30 M342t Evolution

Or just google the link below.

forums.bimmerforums.com/forum/showthread.php?2121463-e30-M342t-Evolution

[RarlyL8]

Yes you could use the thremol reactor replacement pipes for a "poor man's twin turbo". I mocked this up several years ago using K16's from a 993tt. Short adapters and you're there.

[Damon in STL]

RarelyL8,

Thanks for the response.

So, the reason this has not really been done is not due to an "engineering flaw" in the design and layout, but more about the negative connotation of using something that was a band-aid to a problem caused by emissions standards and that it is inexpensive.

I have SSI headers and my first searches showed people cutting the header just after the 3 to 1 merge. This appears to be more work.


As for the snide remarks from some.....there is a big difference between "Poor" and "Cheap with some skills". My background is engineering and project management and I'm not afraid to think outside the box at times or get my hands dirty. As an example, over the years I've wanted to learn metal fabrication skills....so I purchased and learned how to use a Mig, Plasma Cutter, and recently a TIG.

Another example of "Poor" vs. "Cheap with some skills" (Pic of my garage recently): This is what happens when you need to replace a $4 gasket on your BMW. You end up removing the alternator, power steering pump, oil cooler lines, both front axles, front driveshaft, front diff, install new motor mounts, drop the front sub-frame......and use nearly every tool in your arsenal!!!!!

[RarlyL8]

The problem with using the thermal reactor replacement pipes is that they are very cheap mild steel. Every set I have ever seen is cracked including the set used for the mock-up. You know there is no free lunch. That's why we use 321 stainless, it is expensive but will not fail even under track conditions. Here is what we build for the twin turbo conversions:

[Tippy]

Originally Posted by Damon in STL

Who pissed on your Wheaties?

Um, what?

[Ollies930]

Probably not that much of a big deal for you, considering the amount of work you put into the BMW, but if you use the thermal reactors and place the turbos where RarlyL8 shows them, I think you will have to move the dry sump oil tank. Nice work on the Beemer BTW.

[Damon in STL]

Originally Posted by Tippy

Um, what?

Sorry....took your comment as a sarcastic suggestion for a "Boy Racer" wannabe shooting for 900 HP using a turbo that would have high delta T's during their use as a good application.

If that was not the intent....I apologize.

[Damon in STL]

Originally Posted by Ollies930

Nice work on the Beemer BTW.

Thanks!



RarleyL8, thanks for the pic and info on the materials used. This deeper elaboration makes sense.