Rotrex C30-94 supercharger install and modification: pulley choice
 

Hi everybody,

I have a TTS Performance Supercharger kit, base on a Rotrex C30-94, RC750 injectors and Walbro 255 l/h fuel pump.
This kit has been removed from a RHD AP1 and the french tuner decided to limit the engine RPM to 8500 "by safety". The car made 376 bhp and 322 Nm.

I now have to install it back on my RHD AP1 my2002 (with 2004 2.0L inside) and might do some modifications on the installation (some things can be better fixed), and maybe on the piping and intercooler.

But first I have one main question: the crank pulley is a 125 mm and I suppose the SC pulley to be a "standard" 110 mm (I have to check), which is made to respect the max input speed of 10 500 rpm for the C30-94, with a 9 000 rpm engine speed.

The question is: if I tune the EMS to max 8 800 rpm (or less), then I can go for a 105 mm SC pulley and still respect the max C30-94 speed. Would this be a way to get more boost and mode torque/bhp ???
Or is it better to stay with 110 mm pulley and full 9 000 rpm range ???

Thanks for your answers.

All the trq you will make out of that motor happens under 8500 rpm supercharged and minimal increase in hp as it starts to taper off but still does increase above 8500. So that said, your going to make more peak trq output with the current higher boost pulley but 8500rpm limit, and hp may be a wash because of the lower boost pulley option but higher engine redline. I would probably stick with the higher boost pulley and lower rev limit in this particular case.

Thank you for your answer and precision.
I still have to check which pulley I have, all I know is that the tuning has been made with a 8500rpm redline but I am not sure of the pulley size actually fitted.

:thumbup:

As my TTS kit is an old version (2015 with C30-94), I have some problems to find precise technical informations on it.
So yesterday, I made a lot of measurement on the various parts of my kit, in ordre to know what could be improved.

Here is what I have:

• Supercharger is Rotrex C30-94, inlet 3", outlet 2".
  Rotrex théorical data: power range 197-435hp, max mass flow rate 0,39kg/s, max pressure ratio 2,52, max input rpm 10 500. (see complete datasheet)
• Crank pulley is ø125mm, SC pulley already is ø105mm. => that means I have to keep a tune with max 8800rpm to respect the SC max rpm.
• Oil cooler (for Supercharger oil) core is: 230x75x50mm (9"x2.95"x2").
• Intercooler core is 450x160x90mm (17,7"x6,3"x3,5"). Inlet is ø50mm (2") and outlet is ø63mm (2,5").
• Intake (air filter) piping is ø76mm (3"), hot piping is ø50mm (2"), cold piping is ø63mm (2,5").

The installation on the previous car was made that way:

https://cimg4.ibsrv.net/gimg/www.s2k...8e72bb4661.jpg
https://cimg5.ibsrv.net/gimg/www.s2k...826f95a6eb.jpg
https://cimg5.ibsrv.net/gimg/www.s2k...e3740e40f8.jpg
https://cimg3.ibsrv.net/gimg/www.s2k...fc8f63a147.jpg
https://cimg6.ibsrv.net/gimg/www.s2k...4a17a658fb.jpg
https://cimg4.ibsrv.net/gimg/www.s2k...1c8ef28bdc.jpg
https://cimg6.ibsrv.net/gimg/www.s2k...57b4d83515.jpg

The hot piping goes on the left of the engine radiator, and then comes in the intercooler from the top right end.
The cold piping comes out of the intercooler from the left, turns around the radiator, passes just next to the radiator drain valve, and the goes up to the throttle body.


What I want to study is:
- improving intercooler size
- improving hot & cold piping routing, and size maybe ?
- improving air intake with a "K&N CAI Style" home made compartment/partitioning

The objectives are:
- burn cooler air, to reduce engine heat
- get some more bhp if possible

I also have the possibility to make a flexfuel tune: SP98 (in France, is equal to US Oct 93 i think) and E85 (Ethanol 85%). But not sure about the interest, and the risks of E85 for the fuel tank/pump/lines/injectors if my car stays 1 month or more without running (which is frequent).


I would be glad to read your comments and advices on my build.
Thanks.

Just run a simple water/meth injection kit, will lower IAT better then anything you will do with the intake routing, or even running E85 for that matter. Cant lose.

I absolutely don't know anything about water/meth injection. Supercharging is already new to me, so going with injection is quite affraying for me to be honest :D

My car sits for several months during the winter with E85 in tank, no problems.
If your injectors and fuel pump are up to the task you can get a lot more power with a E85 tune.

Pizzai69...

This might be of some help as I have already done some of this...
https://www.s2ki.com/forums/s2000-fo...-92-a-1086804/

mods begin here...
https://www.s2ki.com/forums/s2000-fo.../#post23945935

Thanks for your experience with E85 !
E85 fuel pumps are rare near my home, but they exist. So a flexfuel tune can be interesting !
I have RC 750 injectors, and Walbro 255 pump: following the first informations I found, this seems to be too small for E85 400bhp tune. It looks like I would have to go ID 1000 at least...

I know your fabulous thread, but had not read it entire. Thanks for the second link for the piping and IC modification, which is quite similair to what I aim to do.
Your car is awesome!

I won't reach that level of perfection, neither that level of power with my C30, but some modifications are interesting :)

I have 3 options:
- don't touch anything, stay 370bhp
- change IC for a bigger one, upgrade hot piping to 2.5" (even if blower output is only 2"...) and cold piping to 3" => maybe 20bhp to hope ??
- do that AND change injectors fuel pump + add flexfuel E85 sensor and tune => maybe 40-50bhp to hope ??

Thank you for the kind words.

Now, to answer your questions...

I have 3 options:
- don't touch anything, stay 370bhp (too boring...and no fun! ...don't do this!)

- change IC for a bigger one, upgrade hot piping to 2.5" (even if blower output is only 2"...) and cold piping to 3" => maybe 20bhp to hope ?? (yes, do this! ...but maybe keep original I/C core and re-work the end tanks...more cost effective than buying a new IC) I'd go 2.75" hot side if you can make it fit...be sure to make all bends and radiuses as gradual as possible and smooth.

- do that AND change injectors fuel pump + add flexfuel E85 sensor and tune => maybe 40-50bhp to hope ?? (yes...this too if you are feeling up to it!)

Good luck! :tipwink:

My actual IC is not that big, it's the Supersport version, see dimensions in a previous post.
I can get a brand nwe IC sucah as 500x300x76mm for less than 170$, maybe this is not worth modifying my actual one...

2.75" hot side: isn't it too big ? I mean, the C30 output is only 2"...
Did you feel some "lag" when upgrading bigger piping ?

Well first you can't just buy any I/C core and expect it to be better than the one you have just because it is bigger...that is only one factor in the equation. It should also have equal to or better flow characteristics. Air flow is one thing that many people don't take the time to investigate, but yet is very important. Since there are many different manufacturers of cores there are also many different core designs and therefore flow characteristics. Regarding lag...no I do not have any increase in lag. Since I effectively shortened the entire flow path the response is actually slightly better than it was before. With a supercharger due to its direct drive to the engine, this lag tends to not be as noticeable in the same manner as a turbo setup. You can see this in comparisons between the TTS kit and the KW kit. The only real difference is the I/C core...from a flow point of view. The TTS kit tends to make a bit more power and have a slightly higher boost level.

Make sure you upgrade the fuel pump wiring, if you haven't already done that.
I think the Walbro 255 should support over 400whp on E85 but there are better pumps out there so it might be worth upgrading after all.

Some people say it is not necessary to re-wire for the Walbro 255.
It was not re-wired on the S2000 that was equiped with my kit, and it worked fine but only 370bhp ...

Due to the thin factory wiring there will be a noticeable voltage drop at the pump.
Now the Walbro 255 flows ~255l/h at 3bar and 13.5V, but at 12V it only flows ~220l/h.
Sometimes it works and sometimes not :)

Thanks for precision ! That is a factual answer.

I understand that, but it is quite difficult to have good informations about the IC Cores.

I found this seller :
https://fmic.eu/420-fmiceu

The inside of the Core looks like the left photo:
https://fmic.eu/89449-thickbox_defau...0x140x65mm.jpg
https://fmic.eu/89450-thickbox_defau...0x140x65mm.jpg

The seller gives bhp indication for each IC. But it still is difficult to know if is flowing better than my actual TTS Supersport one.

Yes I agree. It is difficult to know if one core is better than another unless the manufacturer explains the specifics. In the website listed below you will see specifications in their listings for intercoolers that shows the cfm and the pressure loss...this is one way of comparing cores. https://www.treadstoneperformance.co...t=Intercoolers

There are many core designs such as bar and plate (the ones you showed in your pictures) as well as tube and fin (what the TTS race kit's core is) and perhaps others I'm not aware of. Generally speaking the more fins per square inch the better the cooling but may have less flow...not to mention the design of the fins. Getting these two in balance is key...as well as for the given application. For example in something such as track use where continuous heat is a major concern one may forgo maximum flow for better cooling but in something like drag racing ultimate flow and horsepower may be the biggest concern and the best flow will be the major concern to keep horsepower as high as possible but for a short duration.

In my experience the TTS Race kit's I/C core has proven to flow better than some bar and plate designs. I'm not suggesting that either is better overall but each has its benefits. In a street application like my car, I personally would choose better flow over better cooling due to the fact that most of the time the car does not see high intake air temps.

I hope that this helps.

Brian :tipwink:

This sure helps :)

Note that my acutal TTS Intercooler is "bar and plate" type. (see picture in previous post)
In my case, I want a track proof car, so cooling is important.

I asked directly TTS for advices: they told me that : "For a C30-94 376 hp is quite reasonable. The intercooler is the restriction deliberately to limit power. So going to our Race intercooler would increase power". I am waiting for a quotation on the race IC, as I can't find it on the online shop.

Ok. We'll that's good to know. I've never seen the Supersport kit's I/C. My TTS Race kit's I/C has a tube and fin core. Excellent!

Good luck then! :tipwink:

Sorry 06S2k07Si you will be dissapointed :D
I have had already too much work on the car (full bushings change etc.), and it is on jack stands since 1 year now! (got a child)

So I have begun assembling the supercharger kit as it is, with no major modification: no big IC, no E85...
Just a few adjustments on pipings and fixations.

Here is how it looks when pre-assembled: nothing fixed because I have to run the car NA to the technicial inspection soon.
https://cimg4.ibsrv.net/gimg/www.s2k...c677777c12.jpg


I am just going to take care about the intake: change this extra-small foam filter (don't like it) by a traditionnal one. And try to install aluminium panels to feed it only wish fresh air.
Also have to install the OCT, rotrex oil accessories, and engin oil cooler.

I hope I will have some time to finish the car in about 2 months (including mapping).

I tried designing some heat shields for the intake, which would look quite similar to the KN FIPK but adapted to my rotrex and pipings.
https://cimg7.ibsrv.net/gimg/www.s2k...88bb89e3cd.jpg


I think I will forget this idea: difficult to adjust, and not really sure about the gain it would produce...

^^ Yeah that is a dinky filter! Definitely a restriction there. What is the pipe diameter? I have a big brand new AEM dryflow which may fit. Or will with a coupler of sorts. I've got a couple other filters as well, which would require a 6" velocity stack coupled in-between to accommodate. All stuff on my shelf I don't foresee needing.

This rotrex is a C30-94 so the intaje pipe is 3". This pipercross foam filter is 3" inlet, but quite small overall and I don't like foam...
I plan to go with this K&N filter:
https://www.knfilters.com/search/pro...x?prod=RE-0910
https://www.knfilters.com/images/l/RE-0910_Dim.jpg

AEM dryflow filter are quite similair to this, I think ?
Do you think I should go to a velocity stack + bigger filter ?

My problem is the diameter of the filter base. Depending on the excat position of my silicone and aluminium intake parts, the filter is quite near the oem fan. I mesured that I should stay with a filter which is about 5.1 to 5.5" of base diameter , if I don't want it to touch the fan (and the heat shield, if I do it...). I guess the velocity stak solution will be bigger than that.

Last thing: do you agree that my heat shield prototype (K&N FIPK style) is useless ? or should I keep the idea of doing it ?

Actually, something like this may fit: the length of the inlet diameter adapter can help me move the filter away from the rad...
https://www.kseriesparts.com/SK2-343-99-0600.html
https://www.kseriesparts.com/graphic...00_500x500.jpg

News :) I need your help again :D

I can't fin any tool to estimate the boost I should have with my pulley sizes : does this tool exist ??
I know the old KW C30-94 high-boost pulley was 100mm and provided 10psi. But I have a 105mm one, and would like to know what boost to expect...

I also had a long conversation with a serious tuner I would like to work with.
He explained me many things, and I have questions about some of them:

• my injectors (RC750) are not the best, and are too small for E85 application. Because of the cost of the ID1050x + flexfuel sensor, i don't plan to change them and would like to stay on pump gas (called SP98 in France).
  This tuner really really really (... :D ) recommends me to go with E85 , not only for power but above all for reliability (cooling, knock protection).
  Is it really that necessary ?! I am not ready for the cost, and would like to stay on a reliable (road & trackday) SP98 tuning...
• This guy would like me to install one EGT sensor to each cylinder ... in order to check/troubleshoot the temperature by cylinder, in case there would be a problem on fuel injection, air intake, or compression or else...
  I think this is extreme, and too much job for me. I did not see many people do that on s2ki...
  Is that really usefull for the tuning ? Maybe only one EGT on the downside of the header could be enough ? Or no EGT at all ?! (my preference, because of job)
• He also recommends a fuel pressure sensor, in order to set a failsafe security in the ECU (in complement of failsafes with oil T°, oil Pressure and wideband). Some job again... for a very rare problem, isn't it ?
• The C30-94 TTS kit I bought made 376bhp and 322nm on the pervious ap1 it was fitted, with the 105mm pulley and TTS Supersport FMIC.
  This tuner thinks the dyno was optimistic and I may not get as high resultats as that...
  What do you think of these numbers ?

Other question: did somebody ever monitor the rotrex oil temperature ? I plan to do it (a sensor connected to ECU) because I don't know if the 9 row oil cooler provided with the kit will be enough on track to keep under 80°C...

I am too considering upgrading my pulley size to 85mm on the C30-94 blower.

Rotrex Calculators
https://www.rotrexshop.com/rotrex-calculators/

85mm ?! what crank pulley size and rev limiter do you have ?

I have a 105mm pulley on the C30-94 and it have to set the limiter to 8800rpm to be 100% of max spinning speed, with 125mm crank pulley.

News again :)

I ran the car and now know that it pushes near to 10psi.
I ordered the Doctronic ProECU-S2K and my tuner still wants me to go for E85 for reliability reasons (and a bit of extra power in the same time of course).

To be honest, going for E85 would cost me about extra 1300$ (ID1050x, ethanol sensor, and extra tuning cost) over my actual setup. And I did not plan this...
I don't really need that extra power. But knock protection and cooling effect are arguments that I am considering.

I need your advices: am I really taking risks, especially thinking about engine temperatures during trackdays, if staying with 93Oct pump fuel ??
Remember my setup:
F20C stock with AP2 retainers
10psi rotrex C30-94 TTS kit, with small "supersport" intercooler
Aluminium coolant radiator + engine oil cooler and thermostatic sandwich plate
Custom Airbox/heatshield with K&N filter
Grade 8 spark plugs
Stock hood, no opening.

10psi is totally reliable on the street. There is plenty of timing/tuning headroom at that pressure with this engine, especially given how it is seeing much less boost through 3/4 of the rpm range not being turbo. Track duty is going to put more pressure on the tuner to set hot peramiters correctly so the engine stays safe. If it were me, i would run a water/meth injection system (and i do). It's more effective in IAT cooling and works just as well for detonation suppressant. You also arent married to running alternative fuels or the cost of moving to E85 components and the compromise of now having to run that fuel and its availability. Sounds like your tuner could be just trying to take the easy way out and make you invest more more so it takes the pressure off of him to tune properly. Water/meth will help give a good margine of safety without any compromises.

@s2000junky how much $$ are you spending on water meth you ever price it out? I get it would be depending on how you drive. your setup how much you are using. Kind just want a ballpark # with usage if you have ever done that. You strike me of the type of guy to do so :)

You can mix your own for the cheapest option, however there is a "convienance fee" with that so not everyone may be up for it. I have done it but these days summit racing sells a case of 4 gal of boost juice for about $35 and will ship anything free with $100 purchase so i order 3 cases at a time becuase its the best deal. Shipping on 4 gal is so spendy otherwise. I go through that 3 cases about once a year or 10k miles. Thats how much i drive my car on average. I have a pretty sizable injection amount as well. So that should give you something to work from for yourself/use.