Front Mount Intercooler Efficency Test Data

I don't think there is ANYONE out there that knows more about turbos than him.

B&B header.
the 934/935 did not use equal length..why?
not impressed with the single slip joints or heater boxes on brains.

We see a minimum gain of 24whp, right in the mid and upper rpms. The engine will have a lower risk of detonation thanks to cooler, denser charge air.

You'll also experience gains in driveability from idle onwards thanks to the "Longneck" design, like the 930-S/SE and C2T/3.6T, whereby the intercooler sits directly atop the throttle body. The original large cast boost recirculation plenum is replaced with a compact valve as used on the 951 and 1991-onwards Turbos.
That momentary dip in torque you get as you give it throttle to pull away from a standstill? Gone. The turbo also stays spooled better when shifting gears.

Because race engines don't care about off boost performance and don't have the street build (turbo, cams, heads, etc that work as a streetable package. Many more considerations for an engine that makes power below 4000rpm.

Those items have been addressed in our latest generation of headers. Cost drives what is considered "standard" versus what is an option. We have built many systems with double slip joints and other nice features that are considered options and cost extra. There is no limit to what can be done.

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Originally I was not sure of the slip joints on Brian's headers, I was thinking leaking like American made headers for muscle cars are known for; but I was actually impressed with how well they worked. I really have not used the heater much to have an opinion on the effectiveness on the heater boxes, when I installed them I lived in El Paso Texas. But now that I live in Montana I expect I'll give the heat exschangers a true test. At least I can get heat with a high performance header which is a plus for me now

Headers, turbo, muffler, intercooler upgrades as already mentioned all add up to a lot more fun. One more thing not mentioned would be to increase your ignition advance. That in itself makes quite a difference in driveability especially around town. There are HUGE threads on the topic of ignition timing. Not sure what year you're 930 is, but if you're in the 80's then it's probably smogged to accommodate a cat converter; in other words, the timing is severley retarded to heat that sucker up for emissions purposes. Drop the cat, add some timing, and reap the benefits. And as for the Lambda, pull the plug and tune around it. Just a problematic POS in my opinion, but then opinions are like arsholes....we all have one.

I have gone through a few turbo upgrades from stock to K27S to GT35 and the GT35 I got from TurboKraft is the best turbo for me, so far. Boost starts earlier and is overall smoother while still providing the awesome overall kick we all like from the 930's. I found it made my car maybe less "explosive" but more useable, if that makes sense. I still get manic acceleration, just not 0% to 100% effect.

I use B&B headers and heat, and they work well and are lighter than stock. There are comments around that some crack over time, but not so far on mine. I can always get welded if needed and not sure if others will or will not crack, as well.

I use RarlyL8 muffler and really like it, though I have a Turbokraft flow through on my shelf. I plan to fab an easily switchable muffler switch using a V flange mount that will let me swap the rarlyl8 for the tkraft and hi flow cat if/when I need quiet and compliance.

I went from stock to B&B short neck to Turbokraft long neck intercooler and was surprised how much a difference each made. The B&B was a drop in install, very easy, and together with the other mods improved power and driveability. The swap to the long neck intercooler was easier to gauge as it was the only change at that time (no turbo changes) - and I noticed the long neck intercooler DID instantly improve acceleration.
BTW I have the B&B on the shelf and want to sell it, so it is available to anyone who may be interested.

I agree with the comment on fuel and timing. I swapped to EFI and the ability to dial in more timing, manage the curve, and to also manage the fuel mix throughout the rpm and load range is an important aspect to not overlook. I think you can do the same with CIS, however after playing with the Brian Leask CIS WUR and accessory components, and also the solid state digital WUR (cannot recall what it was called), I went to EFI and have found it to be better for me. However, I do find I am constantly tempted to ongoing tweaking with settings since it is so easy to use and tune. I need to resist that urge and just drive and let the ECU self tune itself.

My two cents would be to focus on handling, braking, and suspension upgrades and adjustments; turbo, intake and exhaust upgrades; fuel and timing upgrades.

Later you can also consider cam changes, compression increase, lightweight clutch/flywheel, and maybe displacement increases.

Oh, I also installed a WEVO shifter mechanism and coupler, and highly recommend it to help make the shifting less sloppy.

Hope this insight helps, along with the feedback from the others. Have fun! Good Luck.

We only use 321 Stainless which is correct for the application. The thick walled Asian 304 that others use will not hold up to the heat and stress. We have systems on turbo racecars that have been in the field for 10 years now with no cracks. To date I've never had a set returned to repair a crack.
The heat exchangers were designed to be sacrificial. If you have an off road excursion they will break away and can be replaced. The Gen IV headers will have a slightly different heat exchanger design that fits more snugly and should be even easier to swap out if damaged.


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Brian will the new heat exchangers work with the older headers?

Heater works as well as the factory. Which in Atlanta is good enough for me :-)

The lambda in its stock configuration, which is closed loop mixture control at idle, doesn't serve us well today.

However the lambda as a closed loop mixture control mechanism to supplement the existing CIS system off idle with a microsquirt is an excellent tool.

the op has a euro car thus has the better fuel head....a good start assuming he stays cis.

my car was:

modified fuel head
kokelin intercooler
k27hf
b&b headers w/ heat
underground racing custom exhaust w/ burns ss resonator
tial wastegate
gt2 cams
billet blow off valve
air box and intake...some expensive stock retrofit

all mods reversible (cams not so much) and not mods to cosmetics/exterior.


I owned the car car for 15 years and never had issue one. bullet proof and very, very strong!! have fun with your mods!

I did many of the same mods Ferraripete mentioned. I did them all at once and they completely transformed the car. I have RarlyL8s headers with heat, and always found that they put out plenty of heat even in sub-freezing outdoor temps. If you get chilly, just get into boost. The sound truly has no equal. I copied what some on here have done and modified my airbox to fit the TK long neck intercooler.

Mods
TK LNIC
Leask WUR
DC-13 cams
GT35 turbo
RarlyL8 headers
RarlyL8 street muffler
Tial wastegate

http://forums.pelicanparts.com/uploa...1523130655.jpg

A statement, properly few people in the racing industry, also in the 70's would agree to. They understood puls pattern well back in the days, and they did not had a product to promote.
IMO, too much marketing/commercial interests in posts, and IMO wrong information in this statement to promote products (My opionion). I think the question is very much relevant, and deserves some more insight for picking up a product.

For a starter, the equal length marketing hype is one of the easiest pulled "bling bling" USP arguments within low knowledge/high value asset segment not knowing what really happens priory to the turbo entrance. Usually sales words like “billet”, “equal length”, “isolated banks” sells if the segment is not capable of asking the right questions. I will properly take a long beating in this post now from all the RarlyL8 header owners and fans, but truth is IMO however, that the RarlyL8 headers are nice quality, yes a very nice upgrade for street applications, but not state of the art. Several issues could be pointed out on this product in various areas also. It is a commercial product, a business, promoting products, properly (hopefully) paying Pelican for post advertisement (which is ok btw). I have nothing against this nice product, dont get me wrong, what I find sad is the imo increasing amount of wrong facts that seems to float the forum around them, neglecting other designs and best practice. That contribute to a business, not to the forum. And I hope the forum allows, a member, to be critical to a suppliers promotion and knowledge sharing.

BACK to the question, regarding equal lenght. From my experience (and this is purely my own hands on experience), fact is, that if configured correctly, you CAN build unequal length headers and come out just fine – or even a better and more efficient turbo header desing than a snakeroll equal length. That is due to fewer bends and shorter length. You could call such an unequal short pipe length design a "puls separated" header layout, if made correct. The equal length fuss is primarily due to two factors:

• A) tune for optimal venturi effect between inlet runners and end of exhaust primaries which is used primarily for NA, and account above our boost rpm levels, if not building a stroker diesel engine. A lot has to be taken into account to extract any "venturi" gains on a turbo engine and for most people and professionals it does not make much sense - it basically means you have to build it like an NA on a different atmospheric pressure (i.e. boost vs. back pressure ratios carefully measured, linked cam profiles, huge turbine, simulation in calculation programs such as pipemax etc.). Instead most people just turn up the boost, and make sure you have a separated puls layout.
  
• And B) more important and relevant in regards to turbo engines is o keep exhaust pulses not interfering with each other in collectors and block up turbine housing too soon. A key note is turbine efficiency. The turbine effiency is still the same whether the pulses come entering separated in an equal spread out pattern (as from the engine) or separated but not in equal spread out pattern - only are the pulses to be SEPARATED and not to come in together or too close. Meaning shorter primaries can be unequal to a certain extent without having the pulses coming in too close. And for the sake of it, please remember, we are dealing with 4 stroke engines, 720 degree between each puls, two rotation per ignition.

For that reason you never build huge secondary diameter piping in a turbo header application after a merging collector if pulses are well separated. When seeing turbo headers running with looong distance >2-2,5 inch secondary piping to get to equal length, then it is IMO thought out wrong, and completely misunderstood. And I would never call such a design for a "tuned design". Why?, each puls enters ALONE through all pipings when separated, and each puls now loose speed and energy in a looong >2-2,5 inch volume piping. Only if all pulses were coming in together, you would compensate with big volume, and still never such a length. For such layout you would properly believe you are merging 3 cylinders into 1, but that is misunderstood if you have pulses separated. Length of primaries and secondary piping has to be set in relation to cylinder, stroke and ignition cycle and it is possible thereby to gain velocity and less back pressure (more power) compared to a "snake-roll" bent equal length setup. Obvious an equal length turbo header design with few bends, and short distance is ideal and just as good. However adding length, volume and bends without benefits, only add the “bling bling” equal length word to it IMO.

How is it done. In order to keep the pulses separated in a well out sorted turbo header, you can CALCULATE from stroke/cyllinder/ignition setup which tubes could be of which length in order for the pulses not to interfere with each other. Most people make them equal length just to be sure, and hence extend tubes and add bends as a penalty to get to equal length. It is easy to make them equal length if you have the space for it, but if building your self, and you find optimal routes to lay down your pipes, you can take your cylinder/ignition setup into calculation and make beneficial shortcuts. For such reasons among others, extreme tuners change the firing order of engines, also the flat six engine (Pat Williams for one), if space is limited to header design (which it is normally not on the 911).

Having said that, you can have both excellent equal and unequal lenth headers. The most important factor is to keep the "pulses" happy. Pulses don’t like alot of bends, low speed, long distances, and getting in contact with each other. Do it right, and you get them "pulses" happy and hitting your turbine wheel hard individually. Pulses like speed and freedom, just like the rest of us when racing.

Turbokraft also make headers btw. Turbokraft seems highly experienced in turn-key high-end power applications, (and seems aligned with the market developments outsite the porsche community), and to my opinion properly the company that shares its learning most open minded with its customers when buildig these high powered applications. I like the humble- and knowledge oriented approach a lot, when in fact they are properly some of the most experienced. A lot more variable comes to play when you are responsible of a customers savings and BUILDING af full package engine making +800 whp, compared to selling a single product. High power/early boost best practice applies to both race and street applications.

My point is, and purely from my own opinion, I would like to see the commercial interests turn a bit down product-wise in posts, and focus on content rather than dissing other products. It is a balance. Above B&B header comment is another example, no one asked, but still a business is dissing another business product.

@MaRu, you are fine with both RarlyL8 products and others IMO for your purpose. Personally, I would build everything around a twin-scroll setup (single turbo, split turbine housing), choose header design in that direction, primarely due to spool-up. I would never choose the old K27 turbo as I dont care about stock-appearance. Go twin-scroll with a turbine wheel exducer around 60-64mm, and compressor wheel inducer around the same. then you are good for 350whp to +500whp and still within bulls-eye of the map, and safe on back-pressure. Intercooler, go as big as possible.

High power/early boost twin scroll header example by Turbokraft (btw somewhat same layout design as 935 in the 70's, as commented on above)
http://forums.pelicanparts.com/uploa...1490820769.JPG

Excactly.

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Jakob

There are a few things from a technical standpoint in your quite informational post that I would take issue with, not from the standpoint of disagreement per se but more from the standpoint of clarification. For example (not a direct rebuttal) while some of the dynamic advantages of pulse timing are for increasing scavenging in an NA motor are possibly diminished in a turbo motor in general any increase in pumping efficiency in an NA motor will be also valuable in a forced induction motor, although the relative values between each feature might change somewhat. Some features work well at some frequencies and not at others. Hence the comparison between street vehicles and pure race vehicles (I know you know this)

Nevertheless I would argue you are missing one of the most important points, if not the most important point around your complaints.

People want to do business with someone they believe is a "stand up guy" who will stand behind his/her product and cares about delivering service and a quality product, who values their reputation over a quick buck, who'll sit late on the phone on a Friday evening for a long conversation that at best nets them an $800 sale. Someone who genuinely shares the enthusiasm. Other than for dedicated racers, most of us are quite happy picking a well made product that is 80% of the "perfect efficiency" (however you measure that), that "just works", and has the backing of a person/company like that.

Thank you, svcetiquette. I am glad you are enjoying your intercooler. That's a good engine package you have.

An update / point of clarification for the OP and anyone else interested in TurboKraft's Longneck Intercooler: our newest revision (v3.0) does not require modifying the factory air filter housing.

"thick walled Asian 304"-- ???

Brian could you explain in more detail what changes have been made to your 930 headers? I've had a set of your headers on my '87 for 4 years now. While I like the headers, and love the sound when driving, I do not like the leaks at the slip joints.

Had I known about the double slip joint option when I purchased my headers I probably would have gone that route.

It's some sort of S&M thing. Rawknee can help you with this question. :D