Best upgrade turbo for a CIS engine

[spjuvern]

What options are the best today on a upgrade turbo for a cis engine?

I have a euro 964 turbo car
And looking for better spolup and performance

[slow&rusty]

I recommend discussing further with Brian at RarlyL8 Motorsports. He'll have some good options for you.

[1979-930]

I have Rarleyl8 headers with a Garrett GT35R from Turbo Craft. It's a slightly larger than stock performance. You will need to tune with the modified WUR from Leask.

I think the GT30 is a bolt on replacement that will require no added mods. Check with Turbo Craft on that.

[RarlyL8]

For the 964T the bolt-on upgrade would be to modify the existing OE K27-7200. Quicker spool and more power.

[timc]

Pull the turbo and send it to Charlie at Evergreen for his recommended modifications. I'd call him and discuss first, you will be very impressed.

[TurboKraft]

#1: modify the stock K27-7200 turbocharger. It remains 100% bolt-in.
And un-clog that exhaust. Nearly anything helps.

If you want still faster spool-up and a wider torque band, then the GT35R is what you want, but it requires additional work to install (trim opening in sheetmetal over turbo, install new oil feed line, etc.)

[Tonger]

My suggestion is to talk to Chris Carroll at Turbokraft. I am running one of his twin scroll dual wastegate Garrett GT35R header/exhaust systems on my CIS 930 and it made 390 hp at 1 bar of boost at the rear wheels on its first untuned pull on a Mustang Dyno. The car is very streetable and is a lot of fun to drive.

Edit - I see Chris posted above while I was typing. He has been great to work with.

[MZ3 SBC]

Originally Posted by TurboKraft

#1: modify the stock K27-7200 turbocharger. It remains 100% bolt-in.
And un-clog that exhaust. Nearly anything helps.

If you want still faster spool-up and a wider torque band, then the GT35R is what you want, but it requires additional work to install (trim opening in sheetmetal over turbo, install new oil feed line, etc.)

Chris - is there anywhere I see exactyt and completely what is involved in fitting the GT35r.

OP might want to consider plan B above unless he gets lucky. My hunt for a rebuidable k27 7200 that I can send to Charlie to " Raptor "continues....but I am loosing faith. Gotta be a year and half already...

Considering that I have already cut the tins for the 7006....and changing an oil line is not big deal....and assuming I have the fuel up top.....

Would love to see and hear more about Tongers set up? Could you possible post some pictures?

I am planning on a dyno day and man it be great if I had access to 7200 raptor, gt35r and my re-imagined 7006 to comparesame day same car same dyno.

Thanks

[TurboKraft]

Hi, sure — can post detailed photos next week when I’m back

Originally Posted by MZ3 SBC

Chris - is there anywhere I see exactyt and completely what is involved in fitting the GT35r.

OP might want to consider plan B above unless he gets lucky. My hunt for a rebuidable k27 7200 that I can send to Charlie to " Raptor "continues....but I am loosing faith. Gotta be a year and half already...

Considering that I have already cut the tins for the 7006....and changing an oil line is not big deal....and assuming I have the fuel up top.....

Would love to see and hear more about Tongers set up? Could you possible post some pictures?

I am planning on a dyno day and man it be great if I had access to 7200 raptor, gt35r and my re-imagined 7006 to comparesame day same car same dyno.

Thanks

[MZ3 SBC]

Originally Posted by TurboKraft

Hi, sure — can post detailed photos next week when I’m back

Thanks. Your customer Tonger pointed me to a thread where he posted pictures of the GT35r installed.

I visited your online store and see you offer the oil line with the reducing fitting.
I see there are three versions of the turbo and the forst options mates up to the 930 charge pipe and exhaust flange.

In the meantime I will keep looking around for pictures of the tin cutting which I assue is nearest the hozel that the cold side of turbo sticks through tin,

My understanding is the GT35r when compared to the modified K27 turbos, it starts to spool lower providing more torgue and power in the low RPM ( big!!) and carries that power across the curve when comp.

Is the orientation of the GT35r the same as the K27 as far as the downpipe connection and charge pipe connection?

Is there anydown side to to adding the GT35r to CIS car besides the possible fitment adjustments ?

1)AFR can go lean at high RPM...not a downside per se, but a condition which needs to be addressed ??....the specific CIS needs to be beefed up to fuel that turbo to your desired shift point,

2) How about "feel ' or driveablillity ? Like less turbo 'HIT"....that feeling of boost......maybe not a downside to those seeking more HP / TQ , but smoother boost delivery could feel a little less exciting than say a K29....the feel of boost is exciting but the latent explossive delivery of a big turbo also makes the car less driveable ......

3) Any issues with surging? Does it require more than one diverter valve?

4) known installation modifications as previouslly addressed....cutting tins, charge pipe connection to turbo, oil line with checkvalve.

I like the idea that any repairs or modifciations will support the eventual EFI conversion as in adding the GT35r over a 7200 raptor. Swapping out CDI boxes for mutispark or rebuilding a WUR does not

[spjuvern]

Originally Posted by MZ3 SBC

Thanks. Your customer Tonger pointed me to a thread where he posted pictures of the GT35r installed.

I visited your online store and see you offer the oil line with the reducing fitting.
I see there are three versions of the turbo and the forst options mates up to the 930 charge pipe and exhaust flange.

In the meantime I will keep looking around for pictures of the tin cutting which I assue is nearest the hozel that the cold side of turbo sticks through tin,

My understanding is the GT35r when compared to the modified K27 turbos, it starts to spool lower providing more torgue and power in the low RPM ( big!!) and carries that power across the curve when comp.

Is the orientation of the GT35r the same as the K27 as far as the downpipe connection and charge pipe connection?

Is there anydown side to to adding the GT35r to CIS car besides the possible fitment adjustments ?

1)AFR can go lean at high RPM...not a downside per se, but a condition which needs to be addressed ??....the specific CIS needs to be beefed up to fuel that turbo to your desired shift point,

2) How about "feel ' or driveablillity ? Like less turbo 'HIT"....that feeling of boost......maybe not a downside to those seeking more HP / TQ , but smoother boost delivery could feel a little less exciting than say a K29....the feel of boost is exciting but the latent explossive delivery of a big turbo also makes the car less driveable ......

3) Any issues with surging? Does it require more than one diverter valve?

4) known installation modifications as previouslly addressed....cutting tins, charge pipe connection to turbo, oil line with checkvalve.

I like the idea that any repairs or modifciations will support the eventual EFI conversion as in adding the GT35r over a 7200 raptor. Swapping out CDI boxes for mutispark or rebuilding a WUR does not

Very good 4 questions

[16Volt]

Best upgrade for a CIS engine is EFI.

[MZ3 SBC]

Originally Posted by 16Volt

Best upgrade for a CIS engine is EFI.

I am so with you there. It really is the ony way to get the driveability, performance, and safety margins all working in harmony. No more RICH Afrs for cooling cylinders and detonation risk, good fuel economy? want a big ass turbo? no problem! Driving up the rockies to 10K feet ? no prioblem.....hot and humid? no problem! Bad gas.....how about something unusual....good gas? no problem!!

I hear that EFI is so much cheaper today relative to 20 years ago.....

20 years ago EFI cost 15 to 20K and the car cost 20K - almost 1:1

Today EFI is still 15-20K and the car atleast 100K - almost 5: 1

[spjuvern]

For me it’s not all about what is best performance , I have been working with sports/racecars last 20 years and mostly aftermarket standalone EFI.
But it it’s about keeping most of the original ideas and figure out how to make the best of it is more of a fun challenge.

[unclebilly]

How does a GT35 compare to a K27 Hyflo?

I have a K27 Hyflo that did 440 at the wheels at 1.1 bars of boost and over 500 with more. I’m running a BB muffler, 964 cams, coil air intake, and an andial IC.

My k27 needs to be rebuilt this winter so I’m curious about the GT35r.

[RarlyL8]

The GT35 is a larger capacity turbo than the K27-7200 based variants. To compare performance you would need to use engines with the same mods. Headers are pretty much mandatory and other mods such as ported heads, cams, etc will be enhanced as the turbos have such high flow capability. I use modified K27 turbos for stock and mildly modified engines as they are robust, spool quick (all in before 3k RPM at 1bar), pull hard and drop right in with zero mods. For highly modified engines there are plenty of aftermarket choices and the GT35 is a good one.

[Tonger]

Originally Posted by RarlyL8

The GT35 is a larger capacity turbo than the K27-7200 based variants. To compare performance you would need to use engines with the same mods. Headers are pretty much mandatory and other mods such as ported heads, cams, etc will be enhanced as the turbos have such high flow capability. I use modified K27 turbos for stock and mildly modified engines as they are robust, spool quick (all in before 3k RPM at 1bar), pull hard and drop right in with zero mods. For highly modified engines there are plenty of aftermarket choices and the GT35 is a good one.

My Garrett GT35R twin scroll car is running a stock intake, 964 cams, modified CIS, stock heads, stock CDI ignition and Turbokraft headers/exhaust. It’s definitely not a highly modified motor and the 1 bar of boost is all in by 3100 rpm.

[RarlyL8]

Sure it'll work but it's not being fully utilized. That turbo will probably support 100hp more than is being put out.

[MZ3 SBC]

Brian makes a good point.....if we are going to make claims of modification improvements between products....it needs to be supported and validated by data.

I will be adding a GT35r soon. I will be running the turbo on a dyno along side the current rebuilt and modified K27 7006. Lets see where and how each one effects the characteristics of the engine.

Same car, same supporting mods, same fuel, same dyno ,same correction values etc.

I read claims that the modified k27 7200 raptor spools lower and pulls harder than the 7200 and modified 7006....and theGT35r spools and boosts even better.

The modified 7006 is definitelt spooling better than it was when worn out.....but I am looking for LOWER SPOOL AND MORE TORGUE BELOW 3500 lower spool where the majority of my real wolrd happens while NOT GIVING up anything above 6000 where my built motor lives......lets see how things play out. Looks like I can support the GT35r at .9 - 1bar with fuel....so lets see how it goes. If a 7200 raptor is available for sale or to test on my dyno day....and you arecomfortable loaning it to me for a few pulls.......hit me up

[TurboKraft]

Originally Posted by MZ3 SBC

Thanks. Your customer Tonger pointed me to a thread where he posted pictures of the GT35r installed.

I visited your online store and see you offer the oil line with the reducing fitting.
I see there are three versions of the turbo and the forst options mates up to the 930 charge pipe and exhaust flange.

In the meantime I will keep looking around for pictures of the tin cutting which I assue is nearest the hozel that the cold side of turbo sticks through tin,

My understanding is the GT35r when compared to the modified K27 turbos, it starts to spool lower providing more torgue and power in the low RPM ( big!!) and carries that power across the curve when comp.

Correct.

Originally Posted by MZ3 SBC

Is the orientation of the GT35r the same as the K27 as far as the downpipe connection and charge pipe connection?

See below.

Originally Posted by MZ3 SBC

Is there anydown side to to adding the GT35r to CIS car besides the possible fitment adjustments ?

None.

Originally Posted by MZ3 SBC

1)AFR can go lean at high RPM...not a downside per se, but a condition which needs to be addressed ??....the specific CIS needs to be beefed up to fuel that turbo to your desired shift point,

Traditionally, with stock cams and CR, you only have to adjust the CO and richen it up.
If you're running aftermarket cams and/or different compression, then the VE of the engine changes considerably, and you should be adjusting the CIS accordingly by means of adjusting the WUR. The old BTRs got away with turning up the CO to 3.0-3.5, but consequently they ran rich at idle and part-throttle.
Will the stock CIS keep up? To a point, yes, *IF* it is all working to spec -- and it usually isn't because it's 30+ years old and owners tend to defer necessary maintenance. If it's all been remanufactured to spec and your pumps are getting proper voltage and delivering fuel per spec, then start with the factory pressure values and adjust from there as needed.

Originally Posted by MZ3 SBC

2) How about "feel ' or driveablillity ? Like less turbo 'HIT"....that feeling of boost......maybe not a downside to those seeking more HP / TQ , but smoother boost delivery could feel a little less exciting than say a K29....the feel of boost is exciting but the latent explossive delivery of a big turbo also makes the car less driveable ......

Much more linear power delivery, more punch than a K27/hybrid. Yes, you'll always have a second of lag, but it's about as good as you can achieve from a single turbocharger on a single throttle engine.

Originally Posted by MZ3 SBC

3) Any issues with surging? Does it require more than one diverter valve?

Never had a GT35R surge on a 930, even ones with tiny stock 32mm heads and stock tiny cams.
Three times we have fitted 3 cars with dual diverter valves -- Tonger's CIS car, and the other two were EFI cars where customers wanted the valves recirculated. It's not been a "must-do" for most CIS builds, but it's not a bad idea either on an engine that's ported and cammed and making 400hp+. It's a lot of airflow, and all those OEM-style valves with 25mm hoses connections can only divert so much air.

Originally Posted by MZ3 SBC

4) known installation modifications as previouslly addressed....cutting tins, charge pipe connection to turbo, oil line with checkvalve.

TurboKraft sells the following in a complete installation kit:
1. Air inlet coupler & new OE stainless clamps
2. Air outlet coupler & new OE stainless clamps
3. Oil supply line with check valve, oil restrictor
4. Oil drain accumulator with braided scavenge line
5. OE exhaust inlet gasket, stainless bolts, small-hex all-metal locknuts
6. Exhaust outlet gasket, stainless bolts
7. Stainless turbo hanger bracket with hardware -- because while that stock bracket setup is strong, it's just awful to install
8. Stainless turbine heat shield -- reduce radiant heat to the tins, bumper, rear reflector, distributor...



With the latest compressor castings, the opening in the tin above the turbocharger needs only minor trimming:







The turbine outlet flange is offset slightly towards the passenger's side, and has essentially the same bolt pattern but using 8mm fasteners instead of 10mm. In nearly every case, we've been able to bolt up someone's aftermarket muffler and, if necessary, readjust the outlets/tips. Easy.

For the compressor outlet: if the car is using an intercooler that retains the original cast aluminum charge pipe, we modify the end of it to accept a coupler. It's an easy mod that can be done at home with basic tools.