GTScotT

Id honestly love to have a GTS4 over a GTR, there is a certain element of surprise that allures me. Personally, having done the RB20 and 25 things in the past, Id probably try to pick up the shortest ratio diff I can and keep the RB20. Having a good turbo on it that will max out at something like 230rwkw would make for a very fun and respectable car. If I had to have more, I would buy an RB25 donk and retune the exact above setup with non vct cams. That would unlock about 20kw more and all bolt back into place. Doing an RB26 is probably going to set you back atleast 5k more than the above and will still be in stock trim... Only just faster than above if not at all.

isn't that rb25de as is? Uses Rb20 injection etc??? Logic tells me turbo it and save big dollars, then slam stocky gtrs with it. just confirm what motor u have and when i get to a pc I'll comment further...

Consider they are the OEM item for a fairly well tuned OEM motor (R34 n1). Going to an enormous cam would be futile in a search for gains. Consider again that they are well within the motors factory scope and a cost benefit analysis will begin to form. Ultimately when wouldn't a ported head and the right cams be good? I say if your really serious about maxing out what you've got you should look harder at step 1 based cams and relax on the dreams of expensive port jobs. Be it myself I would run a set of gears as it seems the forum has proved they are a bang for buck performer. step 1 cam size can be seen as 25x or milder 26x variants.. GL

The RB is a cancer cell of its own in comparison to a 4G63, Im surprised you even compared them in terms of reliability. And yes the Evo's are thirsty. Go and test drive one at a dealer and see about a trade in if your serious. GL

Its actually a similarly sized turbo to staos ss range, I know he can make you a housing with ease as his bearing cartridges are also Garrett design. I'm far from a fan of the Garrett internal housings, so, be it myself I would ask stao to build me a housing from scratch (not op6).

I gave up my Evo for the simple issue of trouble.. It is a difficult car to drive sedately and for me required far too little effort to get into way too much trouble. The turbo comes on with little to no throttle and speed pickup is blisteringly fast. For reference, a rolling start from 50kph my next to stock evo 4 vs a friends well developed SR-S13 me in 3rd and him in 2nd I would still all out haul away from him. We pushed the envelope further to see just how ridiculous it was, the same could be expected from 80kph with the evo in 4th and the silvia in 2nd OR 3rd. Make note that my evo only had a dump pipe on it and no other mods, 3rd gear also ends at 140kph so 80 in 4th was a 'little' out of the optimal band. I moved to a R33 GTST for the simple factor of price and something to do.. The skyline will more so be the track/weekend car that I found too hard to do with the evo. I honestly paid a pittance for my next to perfect 33 at the time, so given the opportunity to spend 20g again Im pretty sure I know what I would pick.. To my own detriment. For experience speaking sake, if I were building a 700hp car I would buy a GTR. And LOL @ Evo-curious, classic!

Like luvpsi said, there are 'cheap and easy' ways to go about it but they will definitely cost you the better part of 10 grand. Get a manual one then buy a skyline halfcut and bolt it all in... is the easiest way to go by far. Even if its an RB20, it sounds like all you want is a turbo. Be it myself, I would need a good reason to have a R31 to begin with lol... But then if it was what I wanted, I would buy the R33 or R34 half cut, then conjur up a RB2530DET hybrid by following instructions well documented on this site, then get a full exhaust, fmic, fuel pump, good injectors, good afm, tunable ecu and a 500ish HP turbo (id be willing to try an ATR43G3 on this budget project) and get it all together. With epic torque I would saaayyy.... thats the better part of 15 grand though. GL

Push 20psi and tune it harder. Can I get a +1?

Calm down mate, your right about the price.. 500+ for the 4 bolt or 700+ for the v band housings is an outright rip though.. The internal gate price and the price for the actuator is a joke also.

Can OP please note if a custom dump had to be made and if a spacer had to be used on the manifold or if the turbo bolted up and used the same dump pipe design as the stock turbo? If no spacer and same dump flange as stock then the rear housing is one of those choker RB specific items, if not the response actually looks fine and a high strength actuator at 20psi should be employed. I think that will wake it up as stated prior but only if its the Garrett housing and not the special skyline one.

Some facts from an ex evo owner: Evo 4, 5 and 6 weigh 1350kg Evo 7, 8 and 9 weigh 1450kg+ Stock boost on all models is 14psi Gearing depends on what model you have and what country you got it from. US and European models have taller gearing while Japanese have shorter. Evos 4 to 7 have a close ratio 5 speed box, while ADM 8s have a Euro spec 5 speed and JDM 8s and 9s have a cruise 6 speeder. The close ratio 5 speed is the one you want. My Evo was a 4, which has the smallest turbo of the 4-9 range with a td05hr-16g6 9cm, dry on a weighbridge it came in just over 1300 and it had no side intrusion bars in the doors. I had an aftermarket dump pipe and no other mods. Another member on this site with a R32 GTR had his tuned with a HKS cooler, hard pipe kit, full exhaust, pods and heat sheilds, twin plate, 16psi and 264kw atw is a personal friend and had quite a few goes at the evo. I admit he had some advantage over the 160kmh mark.... Enough said about straight line speed really. Not speaking for drivers yet there was no comparison through the royal national park, having driven it myself plenty I can also say it is a cumbersome car where the evo will simply dance and prance along asif mockingly (in certain situations). On the open road I am confident the GTR is the better car, and its even better to drive around at traffic speeds. On a larger sized race track I could also see some stability and speed advantage in the GTR. Apples and oranges really, but to the average hills enthusiast the evo is near second to none. Take it as you will, I havent even watched the said video at the top of the page, just sheer honest opinion.

Mitch, 260 @ 17psi seems fine. These turbos seem to come alive above 20psi, consider that Simon is making roughly 360+ on an ethanol mix and 26psi. If the drivability is where you want it than leave it as is yet obviously dont be scared to screw in more boost as thats hardly going to kill the motor any quicker (provided its tuned right). Glad to hear its making the right numbers for what youve got atm, and also glad to see your doing it all through a sloppy auto! Shows your setup and the new turbo are working well!

+1 not going to be a 'cheap way out'. They dont match to what comes on it and you are far better with a used set of -7/9s. GL

MY VTEC FELL OFF!! I knew it would eventually find its way to SAU, MY TURBO FELL OFF!! Sorry mate had to do it.. In reality its probably nothing to do with the turbo, try to troubleshoot the electrics as stated above and follow the FSM diagnosis methods

The question is: how much better can the GTX be? Its a new compressor wheel stuck onto the same old exhaust wheel. I am least surprised with the results, factors I believe contribute to their lack of excellence must be related to the step away from high and low blades along with larger trim sizes in general. I note that the EFR still use the high and low blades. I think it would be a nighmare to develope such a product in a lab, you have to have the backing of a real world performance application to be successful with this sort of product. If successful surely Garrett would have plastered it all over the web to show everyone their marvel, however there was no such talk. I suspect these were purely lab bred items with limited environment testing. Scotty, not to discredit your setup, I hope it works out really well and I also have faith in the bigger housing. Your workmanship thus far is also VERY impressive, GL.

First diagnose everything and see where you come up. Check compression, fuel pressure, resistance across the usual sensors and diagnostic error codes. Start with the basics, the factory service manual (FSM) can tell you all this. Once you have checked that everything is running as it should.. Then you can start wondering what gremlins you may have.

After much reading, calculating and guessing I am going to say I believe a 7670 T4 IW on a 2.5L 6cyl would just about be completely loss-less. Loss less implying you would always have a turbo under your foot capable of supply enough airflow at all RPMs to match the motors want for flow. Obviously I dont think a 650hp turbo would be standing up hard at 3000rpm like a GTRS, BUT, I do think this turbo would never have leave you waiting and all while seeing a neat 400rwkw. Come tax return I am considering placing an order. If all goes to plan I will buy it with a low pressure actuator and a high pressure one so I can see how it responds to the factory 1JZ ecu. I have a strong feeling this particular sized turbo would almost feel like an OEM item at lower boost levels, after all I think this is what they were trying to achieve.. I could be wrong and may be better off with a 7064 BUT the map seems to plot better on the 7670, provided the larger exhaust wheel doesnt simply account for more lag.. Hopping Gamma-Ti and twin scroll will come to my 400rwkw party for that one!

Do it once do it right. The HKS manifold is a good thing but if its a low mount rather than a high mount you will not have space to run an adapter. Its hard to fit a turbo under the low mount manifolds as it is. If it is a highmount of some sort again you may be hitting the bonnet with an adaptor in place... BUT, a highmount is likely to be stainless which you could just chop off the flange and put the flange you want on it. You need to decide two things, how much power and how much money. 300rwkw you will be wasting your time with a T4 flanged turbo, 400+rwkw you will be spending 20grand in total to get there. If its 300 you want, sell the HKS manifold and get something suitable.. Probably a stock manifold to be honest. If you DO want over 400rwkw, hang onto what youve got and get the right turbo. If its a twin scroll manifold then pick up a T04Z or 3788R. Recent results for the 3788R have been very impressive. Lets just say your an odd ball and want 350rwkw, you can actually get a T4 35R from GCG for $1450, I would say that is a good option.. However a member has recently found a twin scroll 3788R to be about as responsive as single scroll 35R (on a very built *read expensive* setup).. Again it all comes down to BUDGET. GL anyway, this forum has more info than you will ever need... If the info is on another forum another member will find it and put it here

Hey mate, I think your block may be warped to some extent. I recommend you pull it down and have it X rayed and then decked. X raying the block will show you if the problem will simply reoccur with time. If the block is bowed it is likely that the bow is formed deep into the casting and will just continue to warp its form over and over with time. It would take some serious heat to cause such damage.

Missed them lb's didn't you Simon, haha. All round very impressive results anyway, am very happy to see that a size up in turbo can be combated by a move to a twin scroll housing. Time to have another read of the EFR thread.. I need a price in time for tax return.

It appears to be some sort of older tech garrett unit, I found some yanks talking about one of the PNs on a US based forum yet stating different trim sizes to your own. Regardless, if it did 450rwkw on an SR20 theres no way its going to be choking the 3L, simple as that really. If you want a guaranteed result, your better off buying something else that suits the manifold you already have. If you are yet to make a manifold and were going to make one to suit this turbo, give up while your ahead and start over. The world is your oyster. As stated, the AR is almost a pointless number to gauge without knowing the turbos specs. To the point that, more 35Rs run .63 rears without issue than 30Rs do and they are actually the same housing on both.

Thanks

Can we confirm the 3788 fitted is T3 open frame or T4 TS? Very impressed none the less! Lets see 600+ at the tyres

With a budget of 10 grand I would say you could pick up an ex track only civic or similar and a reasonable condition commodore. Commons are more reliable than their ford counterpart IMO and getting an ecotec fitted moddel will mean you could buy a water pump off a 1930s model buick if you needed to. My neighbors are skip and seem to only own commodores, one after the other, they definitely seem to have a good run with them. Most other cars will cost a packet on their own whereas you can get a common for a couple of grand. For the record I watched a pair of office job asian dudes with EK civics running 1.07s around wakefield on the same day I saw a dedicated track GTR competing at 1.06s. On inspection one of the civics ran a near factory drop in B18C from a DC2R and the other ran a mild B16 crate motor. I recently picked up an EG with a mate for 1500, last one I worked one we fitted with DC2R suspension for no more than a grand (new bushes, DC2R sways, used DC2R shocks/springs), B18C conversion costed about 7. You could buy one done for less, a B16 converted example would do the job. GL

I would also say you might have popped a hose off or an intercooler pipe for that matter. The next thing you have to ask; is it still making boost? If zero your turbo is blown. If it is still boosting but it sounds rooted, try find that air leak.. If not you might want to do a compression test. My first car underwent a "rexy conversion" under the same sort of circumstances, was thrashing its guts out and it suddenly sounded awesome! But had no power.. Compression test revealed I had blown the gasket between cyl 3 and 4. GL