Supercharging a 7A

Bandycoot · 24-09-16, 08:05 PM

Does anyone know of anyone who has successfully supercharged a 7A engine? I turbo'd one a few year ago but the turbo lag was horrendous. I still have that turbo send fittings but unless I can hand a way of significantly reducing the turbo lag I won't be fitting it. This is why I'm interested to talk to someone who has successfully supercharged a 7A.

Andy10v · 24-09-16, 08:38 PM

Supercharged AAN in a 90q

http://www.s2forum.com/forum/showthread.php?t=38833

What turbo did you fit to a 7A before? A turbo 7A does not have to be laggy with the appropriate setup.

There are also a couple of turbo and supercharged 20vs on S2forum.

Bandycoot · 04-10-16, 02:08 PM

Hi Andy. Thanks for your reply. Sorry for not getting back to you. Great link by the way.

I turbo'd my last 7A using a turbo kit developed by 034 Motorsport specifically for the 7A. I was living in Dubai at the time and only came home a couple of weeks a year and this was a much easier option than trying to source a suitable engine, rebuilding and then fitting it. It didn't take long to fit but the problem is that it doesn't come on boost until 4000 rpm and this is not good at all. I tried to sort it but without success. The car it was in died a death a few years ago but I salvaged the turbo and fittings. I would like to fit it again but need to reduce the lag. It was OK on the track but on the road it was a pain.

The turbo itself is a Garret hybrid developed by 034. The kit wasn't intercooled and was running a modest 7PSI boost. My plan was to intercool it but never managed to do so before it died.

sam · 06-10-16, 01:03 PM

it must have been a huge turbo or another issue for a 2.3 to not make boost below 4k?? fit a t25 to it for quick spool and about 250bhp.

4v6 · 06-10-16, 01:10 PM

The turbo lag was because of the turbo being mismatched most likely, i once saw an mr2 with a similar mismatched turbo that would make 600 plus bhp at 8000 rpm mind you with the powerband only from 6k upwards, not what you want on a road going vehicle really, better to go a tad smaller than too large.

Andy10v · 06-10-16, 06:31 PM

Do you have any details on the turbo as I believe they used a couple of variations over the years?

Did you use the 034 7A software?

A stock S2 KKK k24 7000 turbo can make 280bhp on a 2.2 with a very driveable powerband. 20vt is lower compression ratio, intercooled and the ECU has a MAP sensor.

I think you would need the correct size turbo, and a standalone ECU to get the most out of the setup.

Bandycoot · 19-10-16, 09:43 PM

Hi guys. Sorry for the delay in replying to comments. My thoughts are that the turbo is mismatched. As for details of the turbo all I know is that it is a garret hybrid of some description. The EU was sent to 034 for chipping and theoretically the whole thing should be just plug and play but that's being optimistic. I am looking to get the boost to come on much sooner than 4000 rpm, 2500 or 3000 would be acceptable In their blurb 034 say with this kit full boost is achieved by 3000. In my experience this is way off the mark.

Targus · 20-10-16, 01:30 AM

my thoughts are that its 034, i'm yet to see anything they do that is worth the money

Andy10v · 20-10-16, 05:26 PM

Current turbo 034 list is a

Quote:

Garrett/Honeywell OEM T-Series T3/T4 Turbocharger with 50-trim compressor wheel, Stage III turbine wheel and .63AR turbine housing rated for up to 340HP, full boost by 3000 RPM

Older

Quote:

Beta version of the kit with the T3-60 vs the T3/T3 that is now making 207whp

Quick google around shows people using T3/4 50 0.63 as 400bhp turbos with 4000rpm spool on 2l engines.

Smaller turbo would give you faster spool.

I think the generic software is going to have to be very safe, so that is not going to be helping things. 7A ECU has no map sensor.

034 list it as 200 wheel hp / 250 crank hp. Intercooled, bigger injectors, more boost and appropriate software is 250 wheel, 315 crank.

For reference a stock S2 k24 7000 turbo 2470 GGA Compressor, and 6.13 exhaust Turbine, gives 280bhp on an S2, nice spool for road use.

Quote:

For compressors, Garret and KKK use a Trim number. Garrett's trim number is a ratio of the area of the top of the compressor wheel to the bottom of the compressor wheel. For instance: When garret says a 50 trim, they mean the area of the inlet is 50% of the area of the base. take a T04E 50 trim wheel. The base diameter of the wheel is 76.2mm(3"). That makes an area of 7.06 sq. inches. The top area is 50% of that or 3.53 sq. in. working backwards gives up a top inlet diameter of 2.12"

"KKKtrim" is a bit different. They specify compressors by numbers like 2760 or 3060. The first two numbers is the base diameter in decimal inches. So a 27## has a 2.7" base wheel. A 30## is a 3" base wheel. The 2nd pair of numbers is the ratio of the diameters (not the areas). So a 2760 has a base diameter of 2.7" and a top inlet diameter of 1.62" likewise a 2672 (rs2) has a base diameter of 2.6" and a top inlet diameter of 1.872" In Garret speak, the RS2 would be a 51.8 trim compressor wheel with a 66mm base diameter. The RS2 comp has a 2.7" compressor wheel (71.12mm) with a top diameter of 1.872". This is a KKKtrim 2770 wheel. Garret Trim is 48.

What use is all this? Say you want a Garrett wheel that will be similar to a RS2 comp's compressor characteristics. Look for a Garret 12 blade compressor wheel with a base diameter of 71mm and a trim around 50.
The original GT35 has a 71mm wheel and a 50 trim. And lo and behold! the map is very similar to an RS2 in terms of where it falls with regards to PR/and flow. The Knee of the map is even similar in shape to the RS2. You'll find these map similarities exist when comparing a K24 map to a similarly sized Garrett compressor.

For turbine wheels and housings. KKK designates their housings with a stamping on the inside of the inlet. Looking through KKK tech papers this number is the A/R of the housing. So a K27 9.11 housing with a 9 stamped on the inside of the housing is a .9 A/R

Bandycoot · 27-10-16, 10:15 PM

Hi Andy. Many thanks indeed for that very comprehensive information. I've been in touch with 034 to find out what they think. They first of all want rolling road readout which I don't have and will be difficult to get without it being fitted right now. They seem to think it could the cam timing is out slightly. Possible as I had the head rebuilt and may have upset tgd timing on reassembly. What are your thoughts.

Cheers

Steve

24-09-16, 08:38 PM	#2
Andy10v Grown up member Classic Audi Club Member Join Date: Dec 2008 Location: Stirling Posts: 861	Supercharged AAN in a 90q http://www.s2forum.com/forum/showthread.php?t=38833 What turbo did you fit to a 7A before? A turbo 7A does not have to be laggy with the appropriate setup. There are also a couple of turbo and supercharged 20vs on S2forum. __________________ 2005 350z GT Sold-1992 3B S2 coupe-RS2+, 996s, konis, forged rods, rear torsen.... Sold-1993 ABY coupe

06-10-16, 06:31 PM	#6
Andy10v Grown up member Classic Audi Club Member Join Date: Dec 2008 Location: Stirling Posts: 861	Do you have any details on the turbo as I believe they used a couple of variations over the years? Did you use the 034 7A software? A stock S2 KKK k24 7000 turbo can make 280bhp on a 2.2 with a very driveable powerband. 20vt is lower compression ratio, intercooled and the ECU has a MAP sensor. I think you would need the correct size turbo, and a standalone ECU to get the most out of the setup. __________________ 2005 350z GT Sold-1992 3B S2 coupe-RS2+, 996s, konis, forged rods, rear torsen.... Sold-1993 ABY coupe

04-10-16, 02:08 PM	#3
Bandycoot Grown up member Join Date: May 2015 Posts: 24	Hi Andy. Thanks for your reply. Sorry for not getting back to you. Great link by the way. I turbo'd my last 7A using a turbo kit developed by 034 Motorsport specifically for the 7A. I was living in Dubai at the time and only came home a couple of weeks a year and this was a much easier option than trying to source a suitable engine, rebuilding and then fitting it. It didn't take long to fit but the problem is that it doesn't come on boost until 4000 rpm and this is not good at all. I tried to sort it but without success. The car it was in died a death a few years ago but I salvaged the turbo and fittings. I would like to fit it again but need to reduce the lag. It was OK on the track but on the road it was a pain. The turbo itself is a Garret hybrid developed by 034. The kit wasn't intercooled and was running a modest 7PSI boost. My plan was to intercool it but never managed to do so before it died.

06-10-16, 01:03 PM	#4
sam Grown up member Classic Audi Club Member Join Date: May 2008 Location: North east Posts: 778	it must have been a huge turbo or another issue for a 2.3 to not make boost below 4k?? fit a t25 to it for quick spool and about 250bhp.

06-10-16, 01:10 PM	#5
4v6 Ex Member Classic Audi Club Member Join Date: Dec 2007 Posts: 5,565	The turbo lag was because of the turbo being mismatched most likely, i once saw an mr2 with a similar mismatched turbo that would make 600 plus bhp at 8000 rpm mind you with the powerband only from 6k upwards, not what you want on a road going vehicle really, better to go a tad smaller than too large.

19-10-16, 09:43 PM	#7
Bandycoot Grown up member Join Date: May 2015 Posts: 24	Hi guys. Sorry for the delay in replying to comments. My thoughts are that the turbo is mismatched. As for details of the turbo all I know is that it is a garret hybrid of some description. The EU was sent to 034 for chipping and theoretically the whole thing should be just plug and play but that's being optimistic. I am looking to get the boost to come on much sooner than 4000 rpm, 2500 or 3000 would be acceptable In their blurb 034 say with this kit full boost is achieved by 3000. In my experience this is way off the mark.

20-10-16, 01:30 AM	#8
Targus Grown up member Join Date: Nov 2012 Posts: 312	my thoughts are that its 034, i'm yet to see anything they do that is worth the money

27-10-16, 10:15 PM	#10
Bandycoot Grown up member Join Date: May 2015 Posts: 24	Hi Andy. Many thanks indeed for that very comprehensive information. I've been in touch with 034 to find out what they think. They first of all want rolling road readout which I don't have and will be difficult to get without it being fitted right now. They seem to think it could the cam timing is out slightly. Possible as I had the head rebuilt and may have upset tgd timing on reassembly. What are your thoughts. Cheers Steve