I would like to discuss the relative merits of these two kits as I am looking to go FI in the future and these two kits stand out as providing what I need for my goals.

For some background, I am coming from an Evo IX, and am looking to improve the lackluster power of the S2k to be more on the level of my former ride, yet maintain streetability, reliability, and the ability to perform the occasional track day.

First, I will display a dyno comparison derived from two AP2 dyno graphs, one from MugenRioS2k and the other from devs2k. Both are intercooled, the Greddy at 7 psi and the SOT at 6.5 psi. Since different dynos are used, the absolute numbers should be taken with a grain of salt, though the relative curves should have some bearing on something in the real world.



As you can see, these kits provide somewhat similar power/torque curves, though the edge goes to the SOT kit for top end and low end grunt. I also understand transient response will be different, so this is only part of the picture.

I intend this thread to be a civil discussion of the relatives merits of both kits. I will list my own thoughts

Greddy Advantages:

• Simpler install
• Cheaper price (4k versus 6.5k)
• CARB approved (not a factor for me)
• Possibly slightly beefier midrange
• More efficient
• More "upgradable" (new turbo, IC, downpipe, or up the boost)

SOT Advantages:

• Instant throttle response (no boost lag)
• Better low end and top end out of the box
• More reliable (?)
• Good customer support

I am especially interested in finding out the relative upgradability and especially reliability for track days and daily driving. I'm looking for input from experts and kit owners, not random hear say. I'd be especially interested in MugenRioS2k's opinion since he was interested in the Greddy kit but ended up moving to the SOT. I'd also like to see if StaticX Motorsports will comment since they sell both, as far as I know.

 

I think the price has gone up now to about 5 grand! Also, I *think* the SOT roots comes with a more 'reasonable' tune than Greddy's base map.

Most important is to find a tuner that can tune the EManage Ultimate. You'd be surprised how many cannot!

I can't compare my kit to the SOT roots simply because I never had experience with it. You "pros" of the Greddy kit are mostly spot-on. I've never had a problem due to the kit itself. I had an issue with some fittings which weren't part of the kit but rather a set of oil sensors I was running.

The Greddy kit offers amazing spool qualities (talking full boost at ~3500) rpms, and and for a turbo kit, very good response. The major downside (to some) is that you cannot extract more power out of it. The ceiling seems to be

 

Upgradability..

SOT > Greddy

Daily Driving

SOT = Greddy

Track

Haven't seen it proven yet by a Greddy owner; Mark (mugen) takes his SOT to the track all the time. The biggest problem with the Greddy will be oil temperatures that might be manageable with an oil cooler.

 

I don't understand why the SOT is more upgradable. It is less efficient, and quite close to the max recommended RPM already.

The TD05h-18g turbo should be able to boost up to 20 psi relatively efficiently and as a 40 lb/min turbo should be able to flow up to 400 hp. Is the limiting factor here the engine compression ratio?

On that note, as far as the engine is concerned, isn't a PSI a PSI? For two kits at a given RPM, PSI, Inlet temperature, and Timing Advance, isn't the stress (e.g. cylinder head pressure, temperature) the same?

The big difference appears to be the self-contained oil system on the SOT kit, which may allow lower engine oil temperatures overall. But other than that, shouldn't the two kits be relatively just as "stressful" to the engine?

Thanks for the thoughtful responses.

 

I've personally riden in Mark's car (MugenRioS2K) and been at various dyno session. I have no direct contact with Greddy.

IMO the roots blower will out perform the Greddy. The turbo is way too small and you can't squeeze anymore power out of it.

The SOT still has some power left and can be upgraded using a smaller pullly. Mark is only at approx 5.5-6.5 psi. I have personally considered the smaller pulley and you could be around 10 psi and approx 400hp (which is my goal, when ever I can save up the money).

You are doing the right thing in doing your research. I've asked very knowledgable people on this forum in person about turbo vs supercharger, and a very wise man once told me "Do you care if your engine blows up? If yes then go supercharger" (ok better put my flame suit on). That has stuck with me and it is why I will go SC.

 

First and foremost I am not paid by either SXM or SOT.(I have a full time engineering job)
Some might suggest I get paid by SXM by other means like cheaper parts ( I do not receive any additional compensation then everybody else in my local car club that is sponsored by SXM)
When I bought my SOT beta kit I paid full price (actually a little bit more then the MSRP due to a larger, and unnecessary, capacity Intercooler)

SO with that out of the way.

To stay with in the rules I can not post pricing, availability, or thing of that nature; lets keep this thread technical only.

URBAN_DK dyno graph ( confirmed good data)

Givens of that plot
Greddy ULT
approx 40K on the motor at the time of the dyno
Vtec at stock point
Mugen AP2 Header
Stock OD TP
Stock catback
Motor untouched ( not even so much as a valve adjustment )


Currently the car is
ULT
vtec at 4000
Mugen AP2 Header
Stock OD TP
Mugen AP2 catback

By moving the vtec down to 4K the TQ in the 4000-6500 range is near flat about 218.

With the Mugen AP2 exhaust Mid (3-6.5k rpm ) TQ was bumped up to about 220wtq with peek TQ= 220 at about 7000 and moved max hp from 315 up to 330



Some upgrades that will be going on the car in the next couple of months
Upgraded outlet manifold
Improved design for increased air flow velocity and mass flow.
This is the same manifolds that the Miata guys upgrade to on there MP62

 

I am not sure on the specifics of the roots blower; however, just by reading Mark's posts, it seemed that it is upgradable. I'm sure he'll answer this later on.

The Greddy turbo T518z runs out of flow on the F20/F22. I know on other cars the T518z has been used with great success in achieving high power levels, but those engines are simply not as efficient as ours. However, it is due to the size of this turbo that it achieves a great midrange even on a log manifold.

If I had to compare the T518z to a GT-type, I'd say its close to a GT28rs, which if you used another log manifold kit like the Inline, you would see similar power levels (

 

I looked at both of these went Greddy and would never do it again.

If I had to do it again Inline pro offers a small turbo 5965 that is similar to the Greddy but you have some flexibility with he kit not offered by Greddy. I would buy the base kit with Ball bearing upgrade, oil filter relocation kit, Hondata EMS w/ Boost Solenoid, 750cc RC injectors, Science of Speed 2.5 bar map, Wideband O2, and Berk HF Cat.

I wanted a screw but could not find one, I did come across the roots system but there were not enough of them on the road for me to try.

 

[QUOTE=devs2k,Nov 11 2008, 11:00 AM] I am not sure on the specifics of the roots blower; however, just by reading Mark's posts, it seemed that it is upgradable. I'm sure he'll answer this later on.

The Greddy turbo T518z runs out of flow on the F20/F22. I know on other cars the T518z has been used with great success in achieving high power levels, but those engines are simply not as efficient as ours. However, it is due to the size of this turbo that it achieves a great midrange even on a log manifold.

If I had to compare the T518z to a GT-type, I'd say its close to a GT28rs, which if you used another log manifold kit like the Inline, you would see similar power levels (

 

Just some quick answers I am sure I have missed some.
UrBan_dk If you believe this is not in the area of data you were looking for let me know and I will remove what ever you want. Its your thread after all.



[QUOTE]
SOT Advantages: