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I’m looking for some help chasing power from my current set-up, failing that, recommendations on what a new set-up should look like.
The current set-up is a completely reconditioned NB 1.8 engine (balanced, forged rods, stock pistons (slightly machined to a lower CR from 9.5:1 to around 9.35:1) NBFL VVT oil pump, new crank pulley, stock head.
The manifold is a ‘flowy log’ with inspiration from Sturovo / people on here, using 1.25” SCH40 primaries. The manifold flange was reverse engineered from the gasket and therefore larger than the ports, this meant the 1.25” SCH40 pipe was actually too small for the flange and needed beating out to fit. The manifold is mildly polished.
The turbo is a port & polished hybrid TD04L-19T (was a TD04L-13T which made 242 whp at 14psi on the old engine). The downpipe is 2.5”, with 2.5” straight through to an MX5Parts back box (muffler). The back box isn’t the best design in the world with a central chamber and 2.25” twin tips, although I have taken the back box off and seen zero difference in spool or power on maps/Virtual Dyno.
The old engine (same setup but standard 9.5:1 pistons) made 242whp at 14psi on the 13T. New injectors (700cc DW’s), 19T billet wheel on the turbo new head and rebuilt engine, produced 250whp at 18psi. To say I was disappointed was an understatement. I was shooting for 300whp and achieved 8 more than before after spending around £2500.
We couldn’t get the turbo to make any more boost on the 10psi wastegate and EBC so plumbed in a small pipe with a hole in it to help the EBC vent more, this achieved ~18-19psi & 250whp.
My current thoughts are:-
· My manifold is crap and needs redoing in the style of Absurdflow / Wittyworks and keep the TD04L-19T and turn the boost up.
· The TD04L hotside is just too small at higher RPMs and is the bottleneck, creating high back pressure and EGT
· The stock head cannot flow enough (although looking at a lot of the builds on here the head should be good for many more horses than I currently have). IAT’s continue to rise up to redline at 18psi and I read when they stop rising this indicates the system has stopped ‘flowing’ per sé.
Sorry for the rambling. I’m quite pissed off with only making 8 more horsepower and 300 really was the magic number I was looking for. I want to easily slide past E46 M3’s, not chase after them and battle to get past.
I'm on crap wifi at the moment so can't upload pics to this post but will try to update shortly.
The hallmark of a maxed-out turbo is "more boost but no power". You're there.
If you want a specific result, the easiest way to do it is to study those that have come before you and duplicate the important aspects of their build. With your bottom end and injectors, you're a hotside swap away from an easy 300whp, with lots and lots of headroom should you decide you want more.
Thanks for the quick responses guys, I'll read the threads and take it on board. I am reticent to change the turbo completely at this point BUT given the instant response stating the tiny TD04L is the issue, I may have to bite the bullet.
Turbo too small. There are many journal bearing garrett clones on ebay, spool is not great, but better woth a good manifold. Patsmx5 has run multiple different setups with ebay turbos, the lowest whp of which was 350whp on a gt2871r clone. 200 dollar turbo, 1000 dollar diy rebuild engine.
Get a tse setup (best spool from bw efr turbo) most expensive, least amount of parts, best quality turbo
or kraken setup (comes with full exhaust for 1100 shipped) but need to choose a turbo contact kraken miata on facebook
Not having any info on your ic setup makes me guess that is also not efficient. Make sure your ic core is a good one, minimize piping bends... Buy a track dog racing over the rad ic setup if you want the easy button.
Thanks Thumpetto007 the intercooler is a generic medium sized cooler from eBay - 550x140x65 with 2.25" pipes.
It's placed as far forward in the NB bumper mouth as possible and I have shrouded in the intercooler and oil cooler, typically the intake air temp pre TB is around 20°c above ambient.
One full pull (after many) goes from ~10°c to ~25°c at 18psi on a 5°c evening. On track it typically sits around 25 -30°c at at 10-15°c ambient, which I believed to be quite good.
Oh really? Thats the first i heard about the tdr not being good. I was under the impression they are the best on the market.
Is the ic core just too small for over 300whp?
Correct. It's a small tube/fin core that simply can't deal with big power.
There are at least 3 other cores that are just as good, but also come in sizes and configurations capable of supporting 300, 400, etc.
I did a 6758 car ~18mos ago for a customer in the Midwest, he asked me to keep his TDR IC and I was not impressed with it. Had I known, I would have insisted on changing the IC setup in that car (~300whp pump gas track car).
I mean the pipe routing is the correct way, but just needs a different/bigger core. I would hope your ic kit goes over the rad. Its the easiest way to achieve the least amount of bends, oem radiator supports are just replaced with longer ones for pipe clearance. Oh and the minor added cost of running hood raisers, not the hood prop.
Are you sure? There are also tons of other VF turbo's that are nearly identical to the 39, they are extremely common here. In fact, I even have a near-new VF48 I'll be selling soon
Sorry for needing to be spoon fed, I am severely lacking in time at the moment although I have managed to read the suggested posts and the EFR is looking very tempting, need my wallet to agree though.
01-06-2018, 02:01 PM
Help me chase 300whp
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