What Is Involved in Going Turbo Blacktop?

[Trekka273]

I have a blacktop 20 valve engine, which I currently have completely stripped to build in to a good race engine for an off road buggy.

However, just recently, I have been thinking about the possibility of putting a turbo setup on the engine. It would mean racing in a different class, against much, much tougher opposition that I would have no chance of beating (a lot of the opposition run $50-$60K turbo and big V8 engines).

What are some of the main things to look out for if adding a turbo to this engine? I no longer have the blacktop rods (have swapped them for a set of silvertop rods). Are the silvertop rods strong enough to cope with the added power? Are there manifolds commercially available for this type of application? Is there anything else that I should look into first, as I think the head could be really good with a decent turbo.

The benefits of using a turbo setup (apart from the added power) are that I more than likely wouldn't have to wrry about buying a pair of good cams, the amount of head work required wouldn't be as substantial as if I were looking for every little advantage from the NA engine, and the exhaust side of things is much simpler as I wouldn't need to be as concerned with trying to get decent lengths in pipes, etc. In these cars if they are turbo you can just run a pipe of about 2ft stright from the back of the turbo and that is it.

Any advice or views would be greatly appreciated.

[Screamn_Sleeka]

IMHO, choose a different engine, 4A doesn't suit the application.
By that i mean it will cost more to make it reliable and powerful than others, such as the 3S-GTE.
The whole point of the 20v heads was for high compression and well designed N/A ports, turboing defeats the purpose since you will have to lower the compression (down to something like the 4A-GZE ratio) and cut out the ports as wide as possible, making them more like the big port 4A.

You might want to confirm you are talking about a 4A-GE, i just assume you are by the way you talk and the usual 4AGE'ers talk.

[Trekka273]

Yes, I am talking about a standard 4AGE 20 Valve blacktop engine (at this stage).

I understand that there are other engines that are probably better to do work on to produce more power. As I don't have the money to compete with the big guys of the sport, who are spending $50k-$60k on hugely powerful and reliable turbo engines or importing fancy V8 units from the US, I thought this mihgt be something fun and a bit different. I am by no means certaint hat I will veen do this yet, it is just a thought.

What do you mean by cutting the ports out as wide as possible? The blacktop already has nice ports on the intake side. I thought with a bit of work on the intake and exhaust side, and the fact that the air entering the engine will be under pressure, the porting of the engine isn't quite as critical as that for a NA motor? I understamd that to get the ultimate popwer of the package all of that needs to be done right, etc, but this wouldn't be a motor that is developed right to the edge, if that makes sense.

[IN 05 NT]

its been done many of times b4,.....

you can get EBAY turbo manifolds for under $300.....

then you need intercooler...if you choose to use one,...

cooler piping,

injectors, are they big enuf?

but hey...money gets you evrything....

[Trekka273]

its been done many of times b4,.....

you can get EBAY turbo manifolds for under $300.....

then you need intercooler...if you choose to use one,...

cooler piping,

injectors, are they big enuf?

but hey...money gets you evrything....

Yeah, money does get you everything, but that is part of what I want to know, would it be more expensive for me goign this way, or going with what I was planning (Cams, pistons, lots of head work, variable cam gears, etc).

Naturally running it as a turbo would make the servicing of the engine more expensive, more regular, etc.

[30psi 4agte]

As much as i want you to go turbo! It will be more expensive.
You will need an aftermarket ecu ...if you dont already have one ??

Cost of a turbo depending on what $600-1200
Then you have injectors / intercooler/ piping etc etc like in05nt says.

The biggest thing stopping you ,I think is the fact that you have 20v pistons! They wont really be very durable in a turbo situation.

In saying all that though ..... The turbo will be the most fun to drive and easiest to extract decent hp from. The torque of the engine will also improve.
Owning a buggie ,Im guessing your fairly handy with fab work so IC piping etc should be of no concern to you.

The other up side is that as you progress with the car in you driving ability and feel the time is right for some more hp, having a turbo is far easier to extract that 30 ood hp more than if you had a N/A motor !!!!!

[Trekka273]

As much as i want you to go turbo! It will be more expensive.
You will need an aftermarket ecu ...if you dont already have one ??

Cost of a turbo depending on what $600-1200
Then you have injectors / intercooler/ piping etc etc like in05nt says.

The biggest thing stopping you ,I think is the fact that you have 20v pistons! They wont really be very durable in a turbo situation.

In saying all that though ..... The turbo will be the most fun to drive and easiest to extract decent hp from. The torque of the engine will also improve.
Owning a buggie ,Im guessing your fairly handy with fab work so IC piping etc should be of no concern to you.

The other up side is that as you progress with the car in you driving ability and feel the time is right for some more hp, having a turbo is far easier to extract that 30 ood hp more than if you had a N/A motor !!!!!

I don't yet have an ECU for the motor at all, but I am planning to buy a Motec regardless of which setup I finally decide to run.


With regards to the pistons, whether I go turbo or not I am looking at changing pictons. If I stay NA, I am looking to get a set of forged pistons (higher compression and oversized), so they won't be cheap. If I were to go turbo, I was thinking that I could get a set of the 4AGZE supercharged engines pictons and put them in. Would that be a problem?

Intercooler piping isn't really a problem. It is all added expense, but it shoudln't be too bad to get a nice setup with regards to that.

[30psi 4agte]

With regards to the pistons, whether I go turbo or not I am looking at changing pictons. If I stay NA, I am looking to get a set of forged pistons (higher compression and oversized), so they won't be cheap. If I were to go turbo, I was thinking that I could get a set of the 4AGZE supercharged engines pictons and put them in. Would that be a problem?
.

Sweet ... motec!

Ahh if you are already gonna do pistons go the GZE route and turbo it for sure!
Even if you get a GZE bottom end and wack your head on that would be the go.

The gze bottom end is very durable and no other money would need to be spent. So if you go that way it could work out to be fairly cost effective!

[Trekka273]

Sweet ... motec!

Ahh if you are already gonna do pistons go the GZE route and turbo it for sure!
Even if you get a GZE bottom end and wack your head on that would be the go.

The gze bottom end is very durable and no other money would need to be spent. So if you go that way it could work out to be fairly cost effective!

Yeah, a previous car that I set up ran the Motec M4 Pro and it was a great computer. Veyr easy to use, very reliable... never, ever had a problem with it.

I will have to look a bit deeper in to some of the costs before aI make a final decision. The next problem that running the turbo would cause is added stress on the 'box and driveshafts/cv joints. I guess like the old saying goes, you get nothing for nothing, but i have to look at all of that as well.

[DX20VT]

I say turbo it also.

Price wise, pistons and ECU dont count as you were planning on doing them anyway,
and I believe that the money you save on cams and headwork, will pay for most or all of the turbo conversion.

Reliabilty wise I would also think that a slightly more standard turbo 4age ( standard as in no huge cams and doesnt rev to 10K like a high strung NA)
would be far more reliable than the NA version.

[MRMOPARMAN]

from the reports on toymods and most toyota forums, the blacktop rods arent the strongest, so in a high revving high load turbo application like what your planning youd be wanting silvertop/redtop rods with the GZE pistons, possibly with flycuts for the extra vavle?

[DX20VT]

from the reports on toymods and most toyota forums, the blacktop rods arent the strongest, so in a high revving high load turbo application like what your planning youd be wanting silvertop/redtop rods with the GZE pistons, possibly with flycuts for the extra vavle?

I no longer have the blacktop rods (have swapped them for a set of silvertop rods).

And he has also said he's using aftermarket pistons so may get them with the 5V cut out's,

but why bother with the valve cuts?
they only bend valves if you break a cambelt,
and even with the flycuts for the 5th valve it still bends all the EXH valves as those cuts are in the wrong place too,
so why wreck the good surface on the top of the piston when you don't have too.

[MRMOPARMAN]

hmm thats a good point. it would probably help if i double read threads next time

[30psi 4agte]

I say turbo it also.

Price wise, pistons and ECU dont count as you were planning on doing them anyway,
and I believe that the money you save on cams and headwork, will pay for most or all of the turbo conversion.

Reliabilty wise I would also think that a slightly more standard turbo 4age ( standard as in no huge cams and doesnt rev to 10K like a high strung NA)
would be far more reliable than the NA version.

Couldnt agree more