Jump to content
SAU Community

Recommended Posts

Hey guys,

I am after some guesstimates on the following.

When should I see boost with the following setup:

rb30dett low CR 8:1

Standard rb26 head & plennum

Garrett 2860-10 twin turbos

HKS Dumps

3.5" with hi-flow cat

70mm GTR FMIC

At the moment there coming on at 4500rpm. I am trying to establish if I have a problem elsewhere, or if it's the low CR and -10's that are just making it a "oink oink".

I know it's not an ideal setup, but that's just how it's ended up unfortunately. My reasoning is that with the rb30, it should still be coming on way earlier than that despite the low CR.

Cheers.

Edited by James_03
Link to comment
https://www.sau.com.au/forums/topic/302960-garrett-2860rb30-question/
Share on other sites

Well the -5's come on around the same on a 2.6ltr.

You've now gone to the big daddy's, but on a bit more capacity. Virtually cancelling out each other. So sounds "around" about right.

Perhaps they might/should be coming on ~300-400rpm earlier but at the end of the day that's what you would assume.

I take it by info thus far you've not played with the cam gears?

There are always gains there which would see it closer to 4000rpm one would assume.

Yeah haven't played with gears yet, that's probably our very next point of call but.

I think I really made a bad choice by going the -10's. The whole reason I did the 30 was for response, it had N1's on before and started to ramp at like 2000 which was a dream to drive.

Ah well, might have to get some half decent cam's for it now.

I wouldn't expect cam's to change the response terribly much :(

I was hoping when i clicked the thread, it was going to have -5's & 26/30 :)

That would be similar to GT-SS on a 2.6ltr... super responsive and 400rwkw... ye baby!

I wouldnt change the cams, if you must, only go to 260's

The low compression will make it feel like a p!g to drive. If you could get CR up to around 9:1 it would feel a lot nicer to drive.

Ash, there's 2 people up here doing that combo currently :rant:

Hey guys,

I will be changing the turbo's and chucking some cams in. Even if the cams help a little I will be happy.

CR is actually 7:1

So what cam's would you guys go for? You reckon nothing over 260's so I was thinking a set of tomei poncams type B.

Also should I go the -5, or the -7 2860's?

Cheers.

7:1?

Are you sure?

If that's correct, do what you can to change that instead of cam and turbo changes

Yeah it pulled up 125psi/cylinder, which is around there. Made shit power on the dyno, tuner did his best with it but. Top end is reasonable, but the 30 doesn't like being up there like the 26 which makes for a real shitter of a motor. I pretty much lost the one thing that didn't make it such a p1g, which was the smaller housings of the nismos I had before.

I just don't know if I have the strength to pull it all down again just to change the pistons over. It's a massive fkn job. It's running a tomei MLS HG too which just seals the deal as far as low CR is concerned.

Any other ways of upping the CR without doing slugs guys?

Or just bite the bullet and strip it down again?

Open to suggestions. Ill probably still go the -5's as you said Ash regardless of what happens with CR.

Pull it down and build it to between 8.5 and 9.0:1

everything else you've got is fine and does not need to be changed.

I know it's an effort, but it's the solution to your problem.

Also, don't believe a 30 won't rev. There's plenty doing 9000rpm without issue, but stick to 8000 cause allthat revving is just extra wear and tear

and unless you want 450rwkw+

you might as well put -5's on there and be happy with a super easy 380-400rwkw.

So combined with the stuff above - could fix the problems where you feel the setup is lacking. Not perfect, but certainly much cheaper.

Ok thanks guys.

Yeah I am going to strip it down again and change the pistons over. I just got it back together again with the -10's too after some crank work lol.

I am going to sell the -10's and put -5's on too. When I built the block which was a while back now, they didn't have rb30det specific pistons, I must have used homo rb30et slugs.

Lesson learnt anyway.

Cheers.

I wouldnt change the cams, if you must, only go to 260's

The low compression will make it feel like a p!g to drive. If you could get CR up to around 9:1 it would feel a lot nicer to drive.

Ash, there's 2 people up here doing that combo currently :happy:

You dont recommend changing cams? are the 270s to big?

How are your 270s with the -10s in terms of driverbility/boost

Thanks

You dont recommend changing cams? are the 270s to big?

How are your 270s with the -10s in terms of driverbility/boost

Thanks

It was a huge choice between 260 270 and 280s.

Doing it again I'd go 260s, the 270s are great but if the power was a tad earlier that would be nice. Reving it to 9000rpm feels great with nice even power and torque delivery which means it's easy to drive quickly. The closest car I've driven power delivery wise is a 997 GT3, there is no big boost hit like a laggy single for example. Yep, i'm very happy with it, 260 cams would just finish it off

Also, it's GTRS's not -10's :happy:

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Welcome to my 2004 Toyota Mark ii IR-V Fortuna (series 2) With a 1JZ-GTE powerplant under the bonnet (hood) it'll give me plenty of scope for power upgrades. For those who aren't familiar with imports, the 1JZ-GTE is a 2.5L 6 cylinder VVTi engine with a single turbocharger. This has the factory R154 5 speed gearbox, along with a aftermarket 2 way LSD differential (brand unknown). Under the arches are a set of CST Zero 1 alloys, 18x9 +30 225/40 up front and 18x9.5 +15 265/35 on the rear. The car was quite low in Japan and there's evidence of the wheels catching the rolled arches/fenders. The tyre's aren't great so I'm in two minds whether to replace both or just the tyres and put up with the wider wheels on the rear. The car still uses stock brakes with the addition of some braided hoses. The exterior is stock with the exception of a BN Sports front bumper and a replacement Fortuna grill  Moving to the interior, the steering wheel has been replaced with a dished MOMO steering wheel (which will get swapped for my Momo Tuner for the time being) Defi Link Gauges are mounted above the climate controls and on the A pillar, the Oil Temp,Oil Pressure,Water Temp and Boost gauges should help with spirited and track driving  The stock seats have been replaced with some retrimmed Recaro bucket seats. Being a larger build these are a little snug, unfortunately the orange isn't for me so I'll look into replacing these down the line. Other modifications include a twin plate clutch, Blitz intercooler, Evolve alloy radiator, a stainless exhaust with decat, HKS EVC-S boost controller and coil overs
    • Apologies for the long read My R34 GTT was up for sale at the beginning of spring due to a few repairs creeping up. The strut tops needed replacing, roof and bonnet (hood) painting (yay for 3 stage pearl) and the underside stripped and treated. I sold the car which allowed me to be in a much better place financially. Leading up to the sale I was already thinking about the replacement. In an ideal world it needed to be a good all-rounder. Something I can mess around with, modify, do track days, do the school run, go on long drives etc.  Options included but not limited to... Laurel C35, Evo 8/9, Civic FD2, Impreza Hawkeye, Aristo and even an Audi S4 Avant (I've already got the Mazda 6 wagon). But there was always one car at the top of the list The Toyota Mark ii JZX110 I found an advert on a Facebook group for an example in Japan, from a seller called Jon at Rising Sun Exports. A few messages back and forth and Jon calls me from Yokohama one morning (or afternoon in his case). He briefly explained the import process, the costs involved and a repeat of the advert. After much deliberation, the price was agreed and the sale was locked in. I've never imported a vehicle so I jumped into the unknown head first. The money transfer was completed through wise.com (fees apply), very easy to use and the money was with him within a day or two.  The car suspension was raised for the vessel and the car dropped off at the port. It was 7 weeks later when the bill of lading was received and the freight invoice sent to me, followed by the export certificate a couple of days after (both digital copies) In the mean time the port had been in contact. I needed an agent to deal with the NOVA (notification of vehicle arrival) along with the tax/duty invoice, this was £75.00. The port also had a fee of £100, I'm guessing to cover the cost of the 10 day 'free storage' and for moving the car off the boat etc. They need a copy of the vehicle invoice, freight invoice and export certificate to allow the vehicle to pass through customs. The vessel arrived on Tuesday 5th August, the tax/duty invoice was generated and sent over. This is generally tax 20% and duty 10% of the vehicle value. Although the invoice came in at a higher amount than I had calculated. Once HMRC had received the payment the vehicle could be released from customs. I thought once the tax/duty was paid you could collect at any point, that's not the case. Your agent will need to book a collection slot, I requested Thursday 7th which was accepted, with a 9:00am slot allocated. It was a 5:00am start from Norfolk heading to Southampton. We eventually found the compound, upon presenting the bill of lading and some ID they released the car (they drove it out of the compound to the front ready for us to load up). The email from the port stated each slot had a 10 minute window, which seemed abit farfetched but the staff said it's not a strict rule. We were there for approx. 30-40 mins in total. A week prior to collecting I contacted my garage and explained the situation, I was able to get an inspection slot that afternoon. For the registration, DVLA require the car to be insured, for this I used a company called Adrian Flux who can insure the vehicle using the VIN number. 
    • Hey guys, looking for these side skirts if anyone can help me out. 
    • Wife and I are still looking for a new home. One condition was a large enough garage for a full-size lift in one bay. Now if only we could find something... We've been looking for almost a year now.
    • Thanks everyone for the ideas! Sadly, ramps are a no go for me. With young kids at home, I do most of my work late at night while they're sleeping. Starting the car multiple times wouldn't be a great idea.  I'll go see one of those new long reach low profile jacks and take a couple measurements to see if they will fit.   
×
×
  • Create New...