Installed SSI System by RarlyL8 + K27S, impressions...

[911st]

B, Was not worried about the exaust design. It is very nice.

More a thought about the turbo's hot side to compressor ratio. I once had a simmilar turbo with a .7 bar Tial WG that would overboost up to 1.1 bar in taller gears (not short gears). However, that was with a B&B system with larger tubes than the SSI (its WG circut was alwas suspect to me) and the intake side that was well opened up and free breathing.

[911st]

B, Sorry, I thought the turbo was a HF variant. My experance probably dose not fit.

[bkreigsr]

Originally Posted by RarlyL8

...The Y-joint can be swapped out for one having dual waste gates should a high flow turbo be used.

Brian, what's the advantage of dual waste gates on a single turbo? Faster elimination of a possible over boost?
thanks
Bill K

[JFairman]

Seems to me there is none other than the $ profit for the guy selling them..
..with one turbo it would just be extra weight where you don't want it.

[911st]

Most the time single is more than adequate.

Double is only needed where the turbo has a large compressor for efficiency's and to support power at higher RPM. Then to give people the low end drivability every one seems to want they put a smallish hot side on it. With this there is potental for the WG to become overloaded and become a restriction. Then the work around it to add more WG capacity with a second.

Some of the K29 quick spools and HF style turbos have bumped up against this depending on the rest of the motors tune.

Another time is where the turbo has a split hot side where the exhaust gasses from each side of the motor are keep separate in support of faster turbo spool. In this case it is best to have a WG on each side.

[RarlyL8]

Brian, what's the advantage of dual waste gates on a single turbo? Faster elimination of a possible over boost?

Yes, dual wategates allow more efficient control of the exhaust bleed which becomes more important with higher flow turbos and higher HP applications. There is one waste gate per bank and the pipe angle much better.

Seems to me there is none other than the $ profit for the guy selling them..

No it is not profit driven. The dual waste gate system is actually less expensive than the single. Just so happens that the smaller waste gate size is used by the ricers. The savings is passed on to the client.

..with one turbo it would just be extra weight where you don't want it.

No the weight is not a factor. The dual waste gate system actually weighs less than the single. That 46mm monster is heavy.

Another time is where the turbo has a split hot side where the exhaust gasses from each side of the motor are keep separate in support of faster turbo spool. In this case it is best to have a WG on each side.

This is another application that lends itself to more precise exhaust waste control. Ben has this system on his car.

[mb911]

here is my setup and no over boost just dead nuts

[iamchappy]

What size dual wastegates do you use then, 38's, 40's?

I likeum.........

[mb911]

Originally Posted by iamchappy

What size dual wastegates do you use then, 38's, 40's?

I likeum.........

38mm v band

[iamchappy]

Kooool.....

[djdawson2]

[quote=jwasbury;4725048]Dave,

I haven't run any scientific tests to measure improvement with this set up. I'm not going to tell you that the new turbo and exhaust has changed my life...it hasn't.

Hmmm... I guess that's a little disappointing. I would think that $5k worth of hardware would result in a substantial "wow" factor. I'm a data guy... love seeing before and after results in any form, be it 0-60, 1/4 miles, or dyno.

I did see your exhaust pics. I imagine a lot of your satisfaction (and rationalization for your wife ) came from replacing some trashed out components with ones of very high quality. Clearly yours were past their wear limit.

Again, nice work... looks great.

Dave

[RarlyL8]

As stated the shining star, and the expense, is the quality. 321 stainless will last longer than 304 and the heat exchangers produce factory-like real heat.
This build should produce good driveability while greatly increasing the torque band while also adding power on top. At stock boost you should gain ~100whp and the same amount of torque. The long gears and smooth onset of boost can make it feel less exciting than the 3LDZ on/off switch.

[911st]

Brian,

I am impressed if you can pick up 100hp/TQ from just an exaust & turbo change at the same boost? Even if that is 85 at the wheels?

I would think a 33% increase in VE would also require an Intercooler and possably larger intake ports/ cams with the exaust/turbo and still might need more boost to get there.

Again, impressive.

[RarlyL8]

Remember the starting point. The USA exhaust system is very restrictive. Just changing the US exchangers to the later J-pipe or Euro exchangers moves the power from 265chp for the US 930 to 300chp for the Euro. That is with the stock 3LDZ and stock muffler!!
So adding headers, a K27 and free-flowing muffler on top of that you can see this claim is easy to meet.
I run stock 0.7bar boost on my personal car using a K27-7200, stock Euro exchangers, B&B intercooler and SC cams which yields 315hp to the wheels. Yes the cams help but I don't have headers so that is a trade-off.

[forwheeler]

Not to hijack this thread but, what is the estimated gain from headers over the euro exhaust?

[911st]

Brian,

Forgot 265hp was starting point. I keep thinking US cars were 285-300hp. Thus 100hp would have us shooting for more like 365fwhp. Still, 100hp is impressive from an exhaust and turbo change but sounds possible w the early US exhaust depending on the car.

Per Bruce Anderson's book a motor w exhaust, ports/cams, shaved heads, IC, and turbo should make about 360-410hp at .9 bar. (say 345-390 at .8) About the same HP as we are hoping for here.

Still, seems an IC is going to be almost a requirement for such a dramatic increase in efficiency. Not only is the stock IC in-efficient but I suspect it is a restriction just like the stock exhaust.

My reference was my C2 Turbo. I had SC cams, opened ports, S2 intercooler (C2 w larger core via Andial), Full Euro injection injectors & lines, blueprinted metering assembly to ensure full pin travel, Andial fueler w custom programmable driver for near perfect on boost 12.2 AFR's through HP peak, B&B headers w custom Borla straight through right exit muffler, new K27-7200, EBC set for 1 bar and a light weight Cup flywheel. We averaged about 335rwhp or about 395 fwhp. Dyno was the type where you removed the rear wheels and bolted the car to the drive units so the ratings might be light. I know my turbo cost me about 30hp as the 7200 could only hold about .85 to .92 bar boost through red line, but even with all my mods I did not have enough fuel to go there anyway. That and a desire for a faster spool turbo is why I went to a K27-7200 after my K29/7006 and early HF/7006 turbos.

If this is right, with all the mods I was making about 80 hp over a stock 91/2 C2 Turbo. About a 19% improvement. Of course, the C2T already had most of the easy efficiency increases done.

[RarlyL8]

what is the estimated gain from headers over the euro exhaust?

Headers do a few things. Off-boost torque is increased which helps driveability, equal length primaries allow each exhaust pulse to hit the collector independently, there is a small bump in high end power and the entire system breathes better. Nothing earth shattering but a good addition to the system.
The more mods you add the more performance you will receive from headers. They are a facilitator if you will.

[JFairman]

I always read and heard the 86-89 3.3 liter USA cars are 282 horsepower stock and thats with the catalytic converter.
I think thats what it says in my owners manual.

If I remember correctly the origonal 3.0 liter 930 was 265hp.

[bkreigsr]

Originally Posted by jfairman

....if i remember correctly the origonal 3.0 liter 930 was 265hp.

234 advertised

[RarlyL8]

'76/7 3.0L 930 - 234chp or 245chp depending on reference book
'78/9 USA 3.3L 930 - 265chp
'78-'89 Euro 3.3L 930 - 300chp
'86-'89 USA 3.3L 930 - 282chp