SuperS Forged Turbo Build

Low Rider

Poindexter
Staff member
#1
After a long silence on the MSC forums, (life tends to get in the way of things sometimes), together with a general lack of blogs overall on the forums, I thought it would be good to make one of my SuperS engine build.

Before I jump in, a little back story will help to set the tone of what's to come...

For those of you who don't know me, I'm somewhat of an "old timer" on the MSC having been a member since 2001. I've owned a white '94 SuperS since 2001 and have kept and enjoyed it since. It was subject to a major restoration in 2007 and finally taken off the road and stored in 2011 when I skipped the country for a few years. After a lengthy time of being unused, it's about time it came out of the woodwork!. Before it retired, it was running a standard CG13DE long block with 264deg cams, Jenvey throttlebodies and an Omex 600 ECU, which made just under 100bhp@wheels.

After being lucky enough to acquire James (Nis) 2000 Sport+ Turbo back in 2014, I've become rather partial to the power delivery that a turbo offers. James and Ed (Fusion Motorsport) put this car together some 10+years ago and it's delivered on it's original intent since then which was to be a reliable and VERY fast road car.

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Cutting a long story short, after making some much needed tweaks, we reached the limits of the engine in its current form and after a thorough session at Surrey Rolling Road, we conceded at 200bhp@wheels from a hybrid GT2854R turbocharger. Power reached a limit due to a number of factors mainly down to the camshaft choice at the time but also because, (due to budget), the engine was built with a standard cylinder head. It also retains the OEM intake manifold, which has been proven to limit the engine's ability to breath above 6500rpm. All in all there were a lot of things holding the car back but a lot of lessons learned along the way. Dynos often get a bad reputation because of arguments over power figures but they prove themselves time and time again as an extremely valuable diagnostic tool.

After building up a very nice spec'd naturally aspirated CGA3DE engine for the SuperS, which had a significant amount of focus put into the cylinder head, I decided to change the scope to bring the best bits of each of my two K11's into one car. So the engine is about to be dismantled and will be re-built with a set of turbo pistons and a suitable camshaft for turbocharged application.

The main difference with this build is, rather than opting for a somewhat random selection of parts (turbo, off-the-shelf camshafts etc), we will be flow benching the cylinder head to obtain flow/lift curves for intake and exhaust, so we can grind camshafts that will fully optimize the flow potential of the head. We can then derive a realistic power target, turbocharger selection and final compression ratio to give us the best package possible. We'll also be scrapping the OEM intake manifold for a Jenvey turbo plenum to allow the head to flow efficiently.

Below is how the car currently stands after numerous modifications carried out over the last few years.

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Low Rider

Poindexter
Staff member
#7
My M10 x 75 socket head caps were delivered today, which allowed me to get the engine up onto it's stand. So, the engine now sits ready for the head to be removed at my leisure.

Royal mail was good to me today. The 100mm square acrylic sheet I need to cc the head also turned up, which means I now have a full suite of equipment to cc the head and calculate the new piston bowl volume :geek:

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Low Rider

Poindexter
Staff member
#8
Mocked up part of what will be our new inlet manifold tonight, mainly out of curiosity so I could have a good look at the overall system taper and start taking measurements to work out how much clearance I have to work with between the engine and bulkhead.

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The Jenvey inlet manifold was port matched when the head work was done. I had some CNC billet trumpets machined out to suit the size of the manifold for use inside the plenum. Those who have used the turbo plenums in the past have stated that the cast trumpets they offer as a default offering have been improved upon by many. Jenvey also state that their standard spun trumpets aren't strong enough for forced induction, so billet trumpets are the only option.

This is pretty low on the list of immediate priorities at the moment, but with the engine out and on the stand it's easy to have a more intimate look at things to come. In terms of the overall build, this is a modification that will allow the engine to breath significantly better than it does with the OEM intake manifold which is designed to produce early peak torque.

I'll re-visit this once the engine has been re-built, as there are more pressing items to sort currently :)

For those who are interested, the full Jenvey turbo plenums look like this.

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pork

Club Member
#9
Look cool man, saw a set of these on a build on retro rides, Renault 5 le car turbo......was awesome

His engine was was the pointing north/south, so had more room I guess.


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SuperUno

Buy & Sell Member
#11
Mocked up part of what will be our new inlet manifold tonight, mainly out of curiosity so I could have a good look at the overall system taper and start taking measurements to work out how much clearance I have to work with between the engine and bulkhead.

View attachment 57128

The Jenvey inlet manifold was port matched when the head work was done. I had some CNC billet trumpets machined out to suit the size of the manifold for use inside the plenum. Those who have used the turbo plenums in the past have stated that the cast trumpets they offer as a default offering have been improved upon by many. Jenvey also state that their standard spun trumpets aren't strong enough for forced induction, so billet trumpets are the only option.

This is pretty low on the list of immediate priorities at the moment, but with the engine out and on the stand it's easy to have a more intimate look at things to come. In terms of the overall build, this is a modification that will allow the engine to breath significantly better than it does with the OEM intake manifold which is designed to produce early peak torque.

I'll re-visit this once the engine has been re-built, as there are more pressing items to sort currently :)

For those who are interested, the full Jenvey turbo plenums look like this.

View attachment 57129
I do think would be one way to install ITB's and still keep the standard ECU setup. You could install this and use the standard TB to do throttle job and you get the MAF values. Would still need mapping but would avoid re-wiring, and new ECU costs....
 

Low Rider

Poindexter
Staff member
#12
I do think would be one way to install ITB's and still keep the standard ECU setup. You could install this and use the standard TB to do throttle job and you get the MAF values. Would still need mapping but would avoid re-wiring, and new ECU costs....
That would be a very expensive way to do it. I've seen people adapt the plenum chamber from a GTIR on several applications in the past.

You can easily obtain a manifold from a 4EFE / 4EFTE and bastardise one of those. Mulholland in Japan used to do it, so there must be merit there.

Or Matt has pre-made tubular manifolds available off the shelf that are machined to accept a standard throttlebody. These are made to improve mid range torque though, so selection would depend upon what one was aiming for, (he's mainly aimed at the rally community).

Either way the car needs to be re-mapped, so there would be costs involved even if it's mapping the stock ecu as opposed to standalone.

I may go ITBs if there's enough room but they would be the 30mm short versions. If not then I would have to compromise with a single throttle, which could potentially make the overall throttle response a tad sluggish due to the increased plenum volume. It's still very much on the drawing board at the moment in terms of final selection.

Planning an electric water pump I guess?

Liking this build - please keep up the posts :)
I'm undecided at the moment. This engine was originally spec'd to be revving to around 8500rpm where cooling problems can arise with a stock mechanical pump, so I spec'd in an EWP to provide more flexibility. This engine will be spec'd to peak around 7500rpm, which means a standard water pump is viable again. I may revert back to a stock pump for simplicity sake. Something to think about while I'm working on the main hardware.
 

Low Rider

Poindexter
Staff member
#13
With such lovely weather, it was a shame to waste it sitting around watching the royal wedding (sorry Harry & Megan), so I decided to crack on and take the head off the engine.

Cam cover off, cams out which revealed a nice set of shimless buckets.

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One of the benefits of running a CGA3 is the longer valve stems. This will make shimming in a new set of cams significantly easier as you can either go for a set of standard followers from someone like Catcams and use tophats to shim or, you can go for individually ground buckets, (which is what this head is).

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Studs all undone leaving just the short block.

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The head now rests on its side which will allow the last of the oil, that I wasn't able to mop up prior to removal, to drain out.

I'll make up a box with cardboard dividers in it, so I can number and place the individual buckets, springs and valves from all but one cylinder. The cylinder which will be flowed will have the springs replaced for light springs to allow valve positions to be easily set.

I'll wait for the flow data to come back before doing anything further, so this will be the last update for a few weeks :)

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Low Rider

Poindexter
Staff member
#15
Ok, so I couldn't stay away and I decided to cc the cylinder head before it goes of to be flow tested. That way I can get a head start on sorting a piston order.

Combustion chambers come out at 23cc on the dot. Factoring in the head gasket dimensions and deck height, that puts the piston bowl volume at 14.3cc. We'll be going for a decent cam in this engine, so we've decided to go with a 9:1 compression ratio.
 
#16
I've been considering a electric water pump for the power gains but don't like the extra worry of reliability,
So I've thought about running a oversize water pump pulley to under drive the impeller, have you heard of anyone doing this before on a cg13 ?
 

Low Rider

Poindexter
Staff member
#17
I've been considering a electric water pump for the power gains but don't like the extra worry of reliability,
So I've thought about running a oversize water pump pulley to under drive the impeller, have you heard of anyone doing this before on a cg13 ?
Yes, it's quite a common modification in Japan and oversize pulleys were quite a common thing listed on various tuning sites. I actually have an underdrive pulley on the engine already from TTV Racing, which achieves the same thing, all be it a more expensive route :confused:

The Davies Craig EWP I have are proven to be reliable. I also considered one because it was possible to run the fans and pump after engine shut-down which helps with heat soak. You also have greater control over pump operation and target coolant temperatures too.
 
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