3100 Topend --> Turbo 3.1 Conversion

[dbtk2]

My sister totaled her '95 Beretta Z26 a few weeks ago and my dad bought the car back from the insurance company for $200. This leaves a 3100 lying around available for me to purchase for a VERY reasonable price. I'm not sure of the miles on the engine because it was replaced shortly before we bought the car with 75k on it, but the car only has 95k on it, so I would imagine the engine has significantly less. Anyways, the engine runs very good and is in very good shape, so it is perfect for a donor engine. So I know people swap the topend of 3100's onto their 3.1's and it is supposed to give a pretty big power gain, especially on the Turbo engines.

I am interested in doing this to my STE, and want to know what all work is involved in doing this. I was thinking I would swap the heads, lower & upper intake manifolds, and throttle body, but if I remember from what I have been told in the past, going as far as the heads is difficult because of the different shape of exhaust ports and because the 3100 is roller and the 3.1 is flat tappet. So, is it possible to just swap the intake manifolds & throttle body? If so, how much work is involved in that, and what kind of power gain should I expect. If I end up swapping the heads also what kind of power gain should I expect with that and what exactly will I need to do?

Any suggestions would be very helpful.

Thanks,

Shawn

[EurosportZ34]

Ohhhh no that would be a bad idea cause then you'll get more top end. Hahaha, well good luck with it if you are going to do it. I'll still be looking for that race come spring!
-bRad

[RareGMFan]

I'm also very interested in info on this swap. Been thinking about it even before I bought the GPs, when I picked up the parts TGP to have a motor for the AWD.

[tyroelite]

sorry, wrong option. i ment the second one not third ops:

[LukeZ34]

I've heard, that if you do the 3100 heads and intake swap, then you'll probably have to upgrade your turbo.. since the Gen III setup flows so much better than the older Gen II..

I could be wrong though.. I'm not sure. :?

[dbtk2]

I've heard, that if you do the 3100 heads and intake swap, then you'll probably have to upgrade your turbo.. since the Gen III setup flows so much better than the older Gen II..

I could be wrong though.. I'm not sure. :?

With stock boost (which I am almost running, my car pushes about 8.5psi boost thanks to a modified boost controller, and thats only 1psi over stock) the turbo definately won't need to be upgraded. But if you are talking about what Jeff M posted in the topic about cams about the exhaust pressure being too high, that is with heads that flow equivelant to ported & polished Gen III heads, which would flow significantly better than stock Gen III heads. Still, there will be more exhaust pressure than stock, and the turbo won't be able to run as much boost, but it should still easily be able to push 11.5psi boost when I get a chip. I have heard that people have problems running much over 14psi with P&P'ed heads, so it shouldn't be a problem running 11.5. I definately won't be running over 14psi boost anytime soon. And eventually I plan to do a turbo upgrade of some sort anyways, just not right away.

But I am still not 100% sure I am going to swap the heads. Swapping heads is quite a bit of work, especially with the engine in the car, and I would still need to get some exhaust manifolds fabricated to bolt up to the heads. (hmmm....can anyone say custom headers ), and head gaskets aren't cheap at all. I think that is a bit more work than I want to do to the engine right now, even though I really want to do it. If I find out that I warped my heads when I overheated the engine on Thursday (it was warm enough for the SES light to come on...oops!), then I will have an excuse to do the swap, otherwise I think I will leave the stock heads there and just do the intake & tb. (please convince me to do the heads, I really want to, I just don't wanna do the work if you couldn't tell)

Shawn

[mfewtrail]

Although this was written for a 93 GP w/ a 3.1, a good bit still applies to this topic, http://www.60degreev6.com/index.php?p=pages&pid=181

[TurboSedan]

that T-too small should be upgraded even on a Gen-2!

i was under the impression that you'd have to install the Gen-3 heads if you wanted to use the Gen-3 intakes? if that were the case, you probably couldn't use the TGP rear exhaust manifold (the important one), or the crossover pipe. if you had to build a custom crossover pipe, you might as well build one with a T3 flange and forget about that T25. then you'd probably need new oil/coolant lines, a new downpipe for the T3, a new turbo support bracket.....

heck just do a custom turbo 3100 and try to replace the 3100 engine with a 3400 later. the only person that i know of that has turbocharged a 3100 is Mick, but he didn't use any TGP parts.
joshua

[no1kicker]

Maybe get a 3100 block and cam to go roller. Then use a TGP rebuild kit to get the hardened crank. And use all 3100 top end.

[dbtk2]

All in all, that page has a lot of useful information, but I have a few questions for anyone that has any clue about these things.

1) Why do I need to swap the power steering pump? (I don't really want to because not only is it going to be a PITA, but the Power Steering pump on the Beretta isn't the best, you can barely turn the wheel when the engine is cold)
2) For the throttle cable, can I just buy one for a GP with the 3100?
3) It says I need the 3100 Vacuum lines, obviously I have these since I have an entire engine, but how do they wire up. Obviously they are different, so does anyone know how I would need to route them to work properly?
4) About the coolant temp sensor, does anyone know if it will work with the '95 heads?


Luckily I have '95 heads & intake, so I won't have any problems with the rocker arms or the EGR.

I know Jeff M did the swap to a TGP, so I may talk to him when he isn't so busy (why is he always SO busy) and see what he did to make it work.

Shawn

[dbtk2]

Maybe get a 3100 block and cam to go roller. Then use a TGP rebuild kit to get the hardened crank. And use all 3100 top end.

I have the whole 3100 engine, so I don't think I would have to get a 3100 block, I'm thinking I could use the one I already have, and if I wanted to do a budget build up, I could use the hardened crank out of the TGP engine also, that would save me some serious money. I could do one hell of a build up and then swap the engines out if I wanted to, but I don't want to do that much work right now, and I don't think the car needs it right now. I think I may set the block aside to leave that as an option for later, but for right now, I don't want to break into the engine that far. The engine doesn't have a huge amount of miles on it, so there is no sense in replacing or rebuilding a perfectly good, lower mileage engine. Also, I don't know how much performance gain there would be switching to the roller valvetrain. I think if I want a bigger cam and such, I will just put it in the stock block. Upgrading the valvetrain in a flat tappet engine is cheaper anyways. (at least it was last time I checked) But all I really want to do for right now is the heads, intake, and throttle body.

If I'm gonna do a serious build up though, a 3400 would definately be going in. If I talk to the Fiero guys I can get a rebuilt 3.4L shortblock for like $580 IIRC. With P&P'ed intake manifolds and heads, the 3.4L upgrade would add some serious power, especially with a bigger cam.

Shawn

[gp90se]

Id say do the top end swap with sum fab'd up headers, your looking at lot more flow from the 3100 heads. The bottom end of a TGP is pretty strong and I would think the better flow would decrease the compression allowing more boost, but I could be wrong. If you do descide 2 do the swap, do a writeup about it.

-Jeff

[TurboZ24]

1) Why do I need to swap the power steering pump? (I don't really want to because not only is it going to be a PITA, but the Power Steering pump on the Beretta isn't the best, you can barely turn the wheel when the engine is cold)

The powersteering reservoir is different on the 3.1 vs the 3100/3400. I believe the pump is the same, but the pulley itself is different.

2) For the throttle cable, can I just buy one for a GP with the 3100?

As long as you don't have a tranny kickdown cable. The 3100/3400 was never used with a manual valve body auto.


3) It says I need the 3100 Vacuum lines, obviously I have these since I have an entire engine, but how do they wire up. Obviously they are different, so does anyone know how I would need to route them to work properly?

You will need the PCV valve line (it's a funky line), but you can just use hose for the rest with T fittings if you want too.

4) About the coolant temp sensor, does anyone know if it will work with the '95 heads?

I believe the 95' heads have a hole for the coolant sensor on them. If there is no hole in the head, there is a 3 wire coolant sensor where the standard ECM sensor goes that should work.

[TurboZ24]

Personally I would use a 3.1 bottom end and a 3100/3400 top end if I was doing something like this. The lack of aftermarket cams is one problem. I can get a billet roller cam for the 3100/3400, but its expensive. You will also be able to retain your A/C compressor, since the 3100/3400 uses a compressor that directly bolts to the block (in most cases). I believe that the W Body 3100 for a while used a stardard V-5 compressor like the 3.1 used, but only the W Body.

[dbtk2]

Id say do the top end swap with sum fab'd up headers, your looking at lot more flow from the 3100 heads. The bottom end of a TGP is pretty strong and I would think the better flow would decrease the compression allowing more boost, but I could be wrong. If you do descide 2 do the swap, do a writeup about it.

-Jeff

I am thinking that is what I would have to do. Custom fabricate some headers for it (headers would be nice anyways, and I think I would be the only TGP with them), and use the 3100 heads. I am not sure if the compression would be changed, but I don't think it will be from what I have read. The compression may be higher with those heads because the 3100 compression is 9.5:1 instead of 8.8:1 like the TGP, but I think the only difference is in the pistons.

And there will DEFINATELY be a write-up if I do the swap. I have only been researching it for a day, and I see that there is a LOT involved, and I wouldn't want others to have to go through the search for info that I am on.

You will also be able to retain your A/C compressor, since the 3100/3400 uses a compressor that directly bolts to the block (in most cases). I believe that the W Body 3100 for a while used a stardard V-5 compressor like the 3.1 used, but only the W Body.

Well, its nice to know that I can retain the A/C compressor for my A/C that doesn't work anyways.

The powersteering reservoir is different on the 3.1 vs the 3100/3400. I believe the pump is the same, but the pulley itself is different.

So there is a clearance issue with it or something? I would think it would be out of the way enough.

2) For the throttle cable, can I just buy one for a GP with the 3100?

As long as you don't have a tranny kickdown cable. The 3100/3400 was never used with a manual valve body auto.

Well, I don't know for sure, but I think that TGP's do have a tranny kick down cable. I know the trannies aren't electronically controlled, so I am guessing it has the kickdown cable. Does anyone know? And if so, how difficult is it to modify the throttle cable to work? (as you can tell, I don't know much about trannies)

Shawn