2G 4g63 Euro N/A tuning options

[Nickolay]

I'm sure this has been asked thousand times over, though h can't find anything with the search option.

I got myself a GS with 4g63 N/A engine with 146hp (I believe).
Are there any options that would increase the hp noticeably?

I've seen a lot of threads regarding the 420a, especially regarding turbo conversion, and how It's not worth it.
Though does it go the same with the 4g63 N/A, or are there more options?

 

[Zack Huffman]

Definitely more options. Basically, anything that fits a turbo DSM will also fit yours. Hard parts would be interchangeable. The wiring would be the only part that might be a little different. I'm not really sure about the details since across the pond here we only got the 420a in our 2G N/T coupes, and there are indeed a few minor differences in the wiring for the 4G64 N/T spyders compared to the 4G63T models. A harness from a USDM turbo model would be mostly plug and play on yours if you absolutely had to go that route though. I've not seen any 2G European spec N/T wiring diagrams to compare.

Super jealous that you guys got the 4g63 in all trim levels there.

 

[Kryndon]

Big post incoming!

First and foremost, you've got three main options:

• Staying N/A and trying to squeeze out power out of all components possible (Very costly, little gains)
  
• Swapping to a whole different engine (Very costly, time consuming, lots of fab work and it wont be a DSM anymore)
• Simply turbocharging the damn thing! (Most efficient in terms of investment per power gained)

I'm sure there are people who can argue for and against each point, and that's fine. Some have made beastly N/A 4G63, some have swapped LSs/RBs in it and ripped up the drag strip. But frankly, the DSM was always meant to be a 4 cylinder turbocharged AWD street ripper, so that's what you should aim for if you want to be in the DSM game and really enjoy it!

----------------------
Now, let's get some basics noted down:

The differences between a USDM 2G turbo DSM and an EU 2G GS are very little, in terms of powertrain and components.

Starting from top to bottom, the cylinder heads are identical. Valves, lifters, oil galleries, springs etc... The only difference is the intake and exhaust camshafts. The N/A cams tend to have higher lift and duration to help with the linearity of the powerband and provide adequate airflow up to 7000 RPM. This is actually good if you use the N/A cams with a turbocharger, because it would allow you to tune for that extra air.

Moving down, the head gasket is also the same, using the same part number. However, some other 4G6_ blocks use identical but thicker or thinner gaskets, so it's good to keep an eye on that.
The 2G blocks are identical for both cars. The difference of switching to split thrust bearing design from '98 to '99 is the same in our EU blocks as well, so pay attention to the actual build date for your car and not "first registration date". But seeing that yours is pre-facelift, it will have the single-thrust bearing, which honestly is fine. Things like ACL main and conrod bearings fit perfectly in EU blocks as they do in US blocks. ALL EU blocks have oil squirters, including our 1G 6 bolts! I'm currently running an N/A block from a '96 GS and it looked identical internally, it had oil jets in the same spots!

The crankshafts are identical, same stroke, length... The conrods are the same too, however the obvious difference are the pistons. They are also cast aluminium but have 10:1 compression ratio and are almost perfectly flat on the crown. For reference, stock 2G turbo pistons are 8.5:1 compression to account for the forced induction. HOWEVER, it has been proven that the stock N/A pistons are fine with small turbos and stock boost, such as a T-25 running up to 14 psi. I personally ran my previous engine like that for some years without any pistons leaving the block. The rods are the weakest link in the DSM/Evo 1-2-3, 7 bolt blocks!

Back to the similarities/differences. The oil pan is identical, however the N/A doesn't have the actual turbo return line hole drilled out. You do have the same flat spot for it, though. So it's as easy as cutting out the middle hole and welding two nuts on the back so you can bolt up a stock T25/16G return line.

The front case and oil pumps are identical, including the balance shafts. All the accessories (AC/PS/Belts/Water pump) are identical. The difference is in the oil filter housing. Some turbo engines have the oil cooler sandwich plate, some don't. But in both cases, the filter housing is different. The turbo one has the high pressure oil supply hard line running from it, to the top of the T25 turbo. On the N/A housing, you can remove the plug and tap into the same supply hole to run any turbo requiring a high pressure supply, or if running things like a 16G, you can just feed it normally from the head (again by removing the plug there).

One thing I forgot to mention is the water pump pipe going to the thermostat housing. It's different in terms of not having the extra water nipple for the turbo coolant line. Additionally, the top part of the thermostat housing (the one with the cap) doesn't have the extra nipple for the turbo coolant return line also. You can simply drill, tap and insert a barbed fitting into the same spot if needed!

Some other differences are in the intake system, of course. MAFs are the same, but the throttle body on the turbo engine features an elbow for the upper intercooler pipe hose. The N/A throttle body doesn't have an elbow, so you will need to make your own set of hoses/piping once you decide to turbo it. The intake manifold is slightly different in terms of nipples and mounting spots. The N/A manifold doesn't have the extra nipple for the Blow off Valve and it doesn't have the hole for the stock MDP sensor drilled. Technically the MDP is only for the EGR system, so you don't really need to worry about it for now.

In terms of electronics, the N/A GS ECU is different than the turbo one, of course. I've heard some people could run a turbo with the stock ECU or somehow chip it, but I haven't seen it done myself so I can't comment. Best is to find an EPROM 2G Turbo ECU and install that. You may need to play around with some of the pins and fuel pump wiring, but there are other DSMers from Europe who have done this and can help you with info I'm sure.

This is the very basic info that you need to form your decision on what to do, I think. Honestly if you really can't find a GSX anywhere near you, and if your GS is in great condition, I would say it's worth to turbo it. You can easily do the conversion either with a stock T25 setup or an EVO 3 16G but with custom intake piping and cooler.

 

[Nickolay]

Well, after looking through what would need to be done, I'm better off looking for a GST.
It's my daily, and considering I got limited mechanical experience it probably would stand on a jack for multiple months

GSX is as good as impossible to find in Norway, and the prices are insane.
Even GST isn't easy to find.

 

[Kryndon]

I'd have to agree with you. Even if you had all the parts for the swap and gave them to a shop/tuner to do it for you, you would never be sure whether they did everything right and it would be a huge risk. And like you said, if you don't have some mechanical experience you may end up doing the swap over a month or more. Although I have a friend who managed to turbo his GS super quickly without having prior knowledge, and he did a great job!

P.S, prices in Norway are "insane" because the salaries you get in Norway are literally one of the highest in the world . Start looking for adverts around Europe. I bet you can find a decent GS-T or GSX for under 5k euros if you look hard enough. But you'd need to first travel across the continent and either drive the car all the way back up or put it on a flatbed. Just for reference, a flatbed from the UK to Bulgaria (both far corners of the EU) is about ~600 euros. So it may be something similar if for example you find one in Spain and want to transport it to Norway.

You just gotta look hard if you really want to find what you want. That's how I found my Talon. I searched every country's most popular used car websites in their own language using google translate. Been doing that for 3 years and then one day I saw the listing for it in Romania in the middle of buttfuck nowhere (literally). Alternatively there might be Roll On-Roll Off ferries that go from the US to Norway. You can use import companies to find you a good GSX from the US and have it transported to Norway. It may end up costing less than finding one for sale in Europe, but it would depend on the condition!

 

[Nickolay]

Yeah, wouldn't be surprised if it took a month.
My prior knowledge comes from motorcycles, and that goes only to a certain limit on cars

Been looking mostly on Scandinavian sites for around a year, plus Germany for GST, though even with all these countries, there's really few out there.
Last time I saw a GST for a decent price was last summer.
Last time a GSX was for sale, it was a project car to 12k euros.

I've considered importing one from the US, though I'm insecure when it comes to buying a car when you aren't there to check it yourself.
Might be some companies who check the car for you before shipping it I guess?

 

[CptDeadPool123]

Big post incoming!

First and foremost, you've got three main options:

• Staying N/A and trying to squeeze out power out of all components possible (Very costly, little gains)
  
• Swapping to a whole different engine (Very costly, time consuming, lots of fab work and it wont be a DSM anymore)
• Simply turbocharging the damn thing! (Most efficient in terms of investment per power gained)

I'm sure there are people who can argue for and against each point, and that's fine. Some have made beastly N/A 4G63, some have swapped LSs/RBs in it and ripped up the drag strip. But frankly, the DSM was always meant to be a 4 cylinder turbocharged AWD street ripper, so that's what you should aim for if you want to be in the DSM game and really enjoy it!

----------------------
Now, let's get some basics noted down:

The differences between a USDM 2G turbo DSM and an EU 2G GS are very little, in terms of powertrain and components.

Starting from top to bottom, the cylinder heads are identical. Valves, lifters, oil galleries, springs etc... The only difference is the intake and exhaust camshafts. The N/A cams tend to have higher lift and duration to help with the linearity of the powerband and provide adequate airflow up to 7000 RPM. This is actually good if you use the N/A cams with a turbocharger, because it would allow you to tune for that extra air.

Moving down, the head gasket is also the same, using the same part number. However, some other 4G6_ blocks use identical but thicker or thinner gaskets, so it's good to keep an eye on that.
The 2G blocks are identical for both cars. The difference of switching to split thrust bearing design from '98 to '99 is the same in our EU blocks as well, so pay attention to the actual build date for your car and not "first registration date". But seeing that yours is pre-facelift, it will have the single-thrust bearing, which honestly is fine. Things like ACL main and conrod bearings fit perfectly in EU blocks as they do in US blocks. ALL EU blocks have oil squirters, including our 1G 6 bolts! I'm currently running an N/A block from a '96 GS and it looked identical internally, it had oil jets in the same spots!

The crankshafts are identical, same stroke, length... The conrods are the same too, however the obvious difference are the pistons. They are also cast aluminium but have 10:1 compression ratio and are almost perfectly flat on the crown. For reference, stock 2G turbo pistons are 8.5:1 compression to account for the forced induction. HOWEVER, it has been proven that the stock N/A pistons are fine with small turbos and stock boost, such as a T-25 running up to 14 psi. I personally ran my previous engine like that for some years without any pistons leaving the block. The rods are the weakest link in the DSM/Evo 1-2-3, 7 bolt blocks!

Back to the similarities/differences. The oil pan is identical, however the N/A doesn't have the actual turbo return line hole drilled out. You do have the same flat spot for it, though. So it's as easy as cutting out the middle hole and welding two nuts on the back so you can bolt up a stock T25/16G return line.

The front case and oil pumps are identical, including the balance shafts. All the accessories (AC/PS/Belts/Water pump) are identical. The difference is in the oil filter housing. Some turbo engines have the oil cooler sandwich plate, some don't. But in both cases, the filter housing is different. The turbo one has the high pressure oil supply hard line running from it, to the top of the T25 turbo. On the N/A housing, you can remove the plug and tap into the same supply hole to run any turbo requiring a high pressure supply, or if running things like a 16G, you can just feed it normally from the head (again by removing the plug there).

One thing I forgot to mention is the water pump pipe going to the thermostat housing. It's different in terms of not having the extra water nipple for the turbo coolant line. Additionally, the top part of the thermostat housing (the one with the cap) doesn't have the extra nipple for the turbo coolant return line also. You can simply drill, tap and insert a barbed fitting into the same spot if needed!

Some other differences are in the intake system, of course. MAFs are the same, but the throttle body on the turbo engine features an elbow for the upper intercooler pipe hose. The N/A throttle body doesn't have an elbow, so you will need to make your own set of hoses/piping once you decide to turbo it. The intake manifold is slightly different in terms of nipples and mounting spots. The N/A manifold doesn't have the extra nipple for the Blow off Valve and it doesn't have the hole for the stock MDP sensor drilled. Technically the MDP is only for the EGR system, so you don't really need to worry about it for now.

In terms of electronics, the N/A GS ECU is different than the turbo one, of course. I've heard some people could run a turbo with the stock ECU or somehow chip it, but I haven't seen it done myself so I can't comment. Best is to find an EPROM 2G Turbo ECU and install that. You may need to play around with some of the pins and fuel pump wiring, but there are other DSMers from Europe who have done this and can help you with info I'm sure.

This is the very basic info that you need to form your decision on what to do, I think. Honestly if you really can't find a GSX anywhere near you, and if your GS is in great condition, I would say it's worth to turbo it. You can easily do the conversion either with a stock T25 setup or an EVO 3 16G but with custom intake piping and cooler.

So I live in EU and I'm trying to do the turbo conversion , what parts exactly should I change, because I find very mixed answers and I don't know what to do, or what to buy, I have a 1996 2g 4g63 n/a