Antlaw

I'm currently in the middle of swapping my engine with an IPP Stage I. I already have a JWT 530BB TT kit with the GT25's. MY question is this: Is it possible to swap the turbos for bigger ones with external wastegates or am I going to have to get a whole new kit to make this work?

rcdash

iTrader: (18)

700bb also require new manifold I believe. Call JWT to see if they have GTX options available. Otherwise you will need a new kit.

wannabuy350z

iTrader: (27)

i have swapped mine with minor clearance adjustments. GT28's

Robert_K

iTrader: (25)

IMO the 530BB kit is perfect match for an IPP stage I block. I wouldn't swap.

djamps

iTrader: (1)

25's are going to blow hot air on a low comp engine (they already do on a stock engine @8psi). I'd at least go with 28's.

Robert_K

iTrader: (25)

The Cost: Benefits is what he needs to figure out. With only pistons and rods the 25's will make for a fun driving experience. Of course the 28's will provide more power but for the cost is the question.

rcdash

iTrader: (18)

I agree GT25s are small for a built motor but some folks like low end torque...

Antlaw

Well, I'll be more specific... I want to make 500+whp. My setup is going to be the IPP stage 1 long block, JWT 530BB kit, APS 3" exhaust, 600cc injectors. Is it possible to get that much power out of what I have?

djamps

iTrader: (1)

No way you'll get 500whp on a low compression engine with those turbos. Maaaaybe 450whp/500wtq if you're super aggressive on the timing and boost.

Antlaw

Thanks for the input guys. Looks like I will be shopping for a new kit.

Robert_K

iTrader: (25)

Get the 28's.

Eno

iTrader: (1)

As RC mentioned as far as I know it's just the manifolds that differentiate between the 530 and the 700. That and the turbos of course. All the existing piping would be pretty close to the same if not the same.

I think you could snooze to 500hp with what you describe (provided you are MT) with the proper supporting mods- clutch etc... on a 700 kit I think you're starting to get into RFS territory around that power level...

With that being said if you're getting a built long block (not sure right off the top what their stage 1 involves) I think you'll find the 700 turbos are a bit lacking- quick spooling but will run out of breath before your block does. The equivalent to the 700bb turbo with more efficient billet wheel would be a perfect balance of quick spool and I imagine close to the same flow through to the top end as the conventional 28s... but judging by what I'm seeing on RC's build the 700 kit requires a totally different manifold altogether to accommodate the new billet style turbos- I think his is custom.

Sylvan Lake V35

iTrader: (23)

Not sure if you ever went ahead with anything, but one manifold and the turbos need to be swapped to make a 530bb into a 700-850bb kit. I think the manifold sells for about $400 I can't recall what the turbos go for. I have always wanted to see what the 530bb with a good amount of meth/water would do on a built block. I would be happier with 450whp/500ftlbs than I would be with 500whp/450ftlbs. Or talk to Jim Wolf and see if he can swap billet wheels into your 530bb kit. Email the support on thier web site they are pretty good and I have even had Jim email me back a few times and if you get him on the phone make sure you have some free time...he likes to talk.

djamps

iTrader: (1)

From my experience the biggest limitation of the 530's are the internal wastegates. Boost is very creepy and inconsistent over 400whp even with porting. If going to the hassle of external wastegates it makes sense to swap the turbos while you're in there.

Sylvan Lake V35

iTrader: (23)

If you're doing external gates...ditch the entire kit it will be cheaper/less hassle in the long run.

Zume

Can you explain what you mean by "hot air". Sam stated this to me many moons ago. My research from the flow vs pressure table on the T25 turbo show the 25 to be pretty ideal efficiency wise at say 12 psi.

I am certainly no expert but I see the JWT 530 set up as 2 turbos each one powering a 3 cylinder engine. And, from the table @ 12 to 14 psi it is right in the sweet spot.

Welcome any input.

Thx

Eno

iTrader: (1)

The question from my limited understanding is whether or not that "sweet spot" is going to result in 500 hp... and from what I'm gathering is being said by the time you're spinning the cold side compressor fast enough to get up to 500 hp... (which I assume isn't going to happen at 12-14psi considering I don't think I can do that with the 700 turbos) the air is going to be so hot from compression and high flow that it would allow for the air expansion necessary to ensure maximum generation of power from the engine.

I'm assuming that as the volume of air going through the compressor side goes up (with larger housings / turbos), that the pressure required to feed the engine to 500 will go down... as pressure requirement goes down and volume goes up... AITs come down.

Am I close?

Zume

Compressor maps are a "fixed amount" in equation of determining what turbo is good for what horse power. If Antlaw wants 500 whp then I would suggest starting at that amount and working backward to determine what and how large a turbo will be required.

Get the Compressor maps (charts) off www. Garrett site and use formulas from a turbo car book (Cork's Maximum Boost) to come up with a required air flow.

If one knows what flow is required then pick a likely turbo and pull up the compressor map...start at the bottom and find the flow you need, move up the map (chart) until you intersect the sweet-spot line then move left to the required pressure.

I don't mean to hijack this thread. In my case at this point I just want the most power that will result from the sweet spot. ....there is no way a GT25 turbo will result in 500whp.

Zume

Pardon me ITNKIN for butching your post.

My limited understanding says that any decent turbo set up is going to seek the "sweet-spot". One would never want to push more pressure then the specific map says to push for the most efficient operation because this would put one fully in the chock zone... and this would be wasteful and yes just hot air...

So to say a turbo is just pushing hot air makes no sense to me...why would one ever build a system that is not fully efficient.

Sylvan Lake V35

iTrader: (23)

Because turbos are expensive and your goals change some time people will push the turbos that are on the small side too hard to reach the new goal i have seen it lots and it often works. No one intentionally use turbos that are too small for thier goals but plans change or budgets shrink. That's the point of this thread he wants to know if the turbos will get him to his goal or does he need new ones...in a perfect world we would all have perfectly sized turbos for our goals and driving style.