Looknig for advice and opinions on turbo option

T

Twinturbo Ranger

Member
Well after a couple years with the KB I've decided I'd like to try something different with my truck. I'm looking at doing a turbo swap as it can give me what I'm looking for, better top end power, better overall power, queiter exhaust, etc... I've had two turbo vehicles before this one I built (hence the name) and one that was turbocharged that I modified. However my knowledge is still limited and this time I want to tackle a custom setup. Here are some of the things I need help with up front.

First my goal is 700- 800 rwhp on pump gas at around 16-18 psi if possible. I feel like the 700 rwhp on pump gas is possible. I want to be able to retain good street manners so a fast responding turbo is necessary. I realize it will not have the KB response, but you know what I mean here. Currently I have a built shortblock with ported heads and Comp 270ah cams. The cams may cause some problems ??

The turbo that was recommended was a GT42-80 believe ?? I was told not to get the ball bearing option as the turbo should spool quick anyway. Thoughts here would be nice.

As far as the headers go, I was looking at possibly being able to use the factory manifolds. Will this limit power or have any other side effects?

Also has anyone done a low mount setup using a oil pump to return the oil instead of a normal gravity feed? I 've got several ideas on mounting location but returning the oil is the problem.

The only other thing before I jump in is the intake. I wanted to use a modified Eaton for a few reasons. Anyway I've seen this done on more than one vehicle and would like to know how it turned out?

I'm sure I'll have more questions, but this is what I need to know before I start.

Thanks Mike
 
I think 700 whp on that combo with pump gas is pretty optimistic. I really think you're going to need more boost than pump gas is happy with to make that kind of power.

FWIW, 16 psi would get you there if your motor was 100% efficient and you turned it 6000+ rpm, and you were able to get the air into the motor at ~ 70 degrees.

Frank passed the 700 rwhp mark on his combo, but that wasn't on pump gas...
 
hmmmm.... If thats the case then this might not be a good option. The 700 rwhp goal on pump gas was one of the biggest reasons I wanted to change. I want to run the factory intercooler I have now along with mu water/meth setup, but I doubt 70 degree temps. This is why I asked though as my knowledge is limited with turbos.

Thanks Mike
 
I don't think 700 is unreasonable. Look at a lot of the guys making 600+ with built motors and that is thier street tune. It is probably safe to say that with a turbo and the HP recovered off the crank and with cooler inlet temps, you would be around 700. Sal from PSP made 800 HP.
 
But Sal didn't do it on pump gas... I didn't say it wouldn't get there, but I find it kind of unlikely it will do it on pump gas. I'm open to be proven wrong. ;)
 
FMOS Racing said:
But Sal didn't do it on pump gas... I didn't say it wouldn't get there, but I find it kind of unlikely it will do it on pump gas. I'm open to be proven wrong. ;)
Click to expand...

I might have to take you up on that in the future....Just waiting on all these turbo kits coming out and for the bugs to be worked out.
 
Twinturbo Ranger said:
The only other thing before I jump in is the intake. I wanted to use a modified Eaton for a few reasons. Anyway I've seen this done on more than one vehicle and would like to know how it turned out?
Click to expand...

Sal at PSP used the modified eaton as a intake manifold. He made 800 HP with it. I seen it in person(the truck and manifold that is) and besides the fact that it looked ugly, it still worked. I am sure something more efficient can be used or made. I don't know if Scott Dunn(guy who owns the truck now) has done anything else to it.
 
I'm pretty confident a GT55 (91.5mm) turbo will get the job done for you (made 847 RWHP at ~14psi on a 6spd LS1 car on 94 oct. pump gas). However, this is a limited production piece which is fairly pricey. I'm pretty sure you could hit that power level with a large frame turbo as well (PT94 on up). As you notice, these are rather big turbos. As you limit the pressure, you're volume needs to make up for it. This will lead you to running larger turbos that usually don't spool quite as well, however, leave you with a lot of potential for later:D The GT4788 has gotten to that range before on Mustangs, however, they usually have less drivetrain loss. It would be a fun turbo for you though:)

On a Forced Inductions 4280 I believe you will run out of sufficient exhaust flow before you get to the power you are looking for. It is pretty important when trying to maximize pump gas power that you get as much exhaust heat out of the cylinder as possible.

I don't know the answer to your factory manifolds question.

On a low mount set-up, many people have done it but I'm not sure if Lightning owners have done it. I generally recommend using a small accumulator (holding tank) below the turbo so that the oil and air can separate (oil becomes foamy as it goes through the turbo) and then it becomes easier to pump.

And I don't know your Eaton answer.

Good luck!
- Brian
 
gasguzzler- Thanks for the reply. I see what you are saying about the turbo size considering I'm trying to stay around a certain boost level. I've learned thru the years that the more boost you run the narrower margin you have in your tune for error, plus theres more heat which would kill the pump gas idea.

When I started thinking about this I figured I'm over 600 rwhp now so I'd pick up 50-75 hp from not driving the blower. That in itself should get me close to my goal. However it seems that it may be a little hard to reach that goal so I may be better off looking at a turbo that can spool fast and work in the 650 rwhp range.

Either way I think I have talked myslef into doing it. I wanted to do it a couple years ago when I did the motor but I did not have time then. I do now and I think theres more help out there now with a turbo on a Lightning so I can get some knowledge there.

I think the biggest thing now is getting the right turbo size and finding out about the exhaust manifolds. That will get me started and I can go from there.

Thanks Mike
 
Lag with a GT55 or PT94 would be a bit much for the street wouldn't it?? I would imagine a PTE76GTS or GT42-80 would easily make those #'s (650rwhp) on pump gas and still have tons of room to spare with excellent spool up. I believe the 76GTS has made over 900rwhp on race fuel on LS1tech.com and the GT42-80 has made 1100rwhp on LS1tech as well.

Gasguzzler is Garrett only making a limited supply of GT55's?? Also how about the GT50?? Are they planning to sell those to the public??
 
The GT42-80 was what was recommended to me by the guys at Forced Induction. More than likely that is probably what I will go with and will just see what the power numbers turn out to be.:)

Anybody know about the stock manifolds?
 
A lot of people have made a lot of power on a lot less manifold than the Gen 2 trucks come with... I'd personally think that wouldn't be too much of a problem, though Brian's comments about exhaust gas evacuation and chamber temperatures is worth noting for pump gas tuning.
 
Okay I yanked the exhuast tonight so I can start getting some ideas. My biggest thing currently is what to do on the hot side. Is there some tables or info on the pipe sizing for the amount of distance the turbo is away?

The reason I ask is I see 3 ways I might do things. My first thoughts are a remote mount turbo which would basically sit were the muffler is. I like this idea alot as the turbo itself would not be far from the header. The two negatives are oiling and a long intake tube which would cause me to do a blow thru setup.

The other is a high single on the drivers side. I would do this a little different then most as I'm wanting to keep the stock fan and not modify hoses if I don't have to. This looks like it can be done, but again in a blow thru application.

The last idea I saw was low mount twins, with the turbo mounted sideways behind the fog light. This also would be a blow thru.

Anyway everyone has their own ideas, but since I have not done a custom setup before I do not know what I should try to accomplish with the hot side to make the turbo spool quick and be effiecent. Thoughts here would be welcome.

Thanks Mike
 
I would feel comfortable running a GT55 on a 5.4L engine on the street, it'll be a little big but nothing horrible. I don't necessarily believe it would be the right turbo for you. I think you would like the GT4788 if you can fit it or the PT88 if you can't fit the 5" downpipe/large frame set-up. The GT4276 can also be suitable for this set-up, although I think Frank5L should be able to shed a little more light on that combo.

Yes, the GT55 is a limited production piece. The GT50 I am not familiar with.

- Brian
 
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