DanJ 374 Report post Posted April 19, 2017 It allows forced induction cars to run a little cooler which in turn allows a little more ignition advance, the same is true for NA but to a lesser extent. An NA car in warm climate will be absolutely fine on the stock thermostat, Toyota/Subaru will have development tested the car in much hotter ambient temperatures than high 30's deg.C. 1 Ade reacted to this Share this post Link to post Share on other sites
surrey86 352 Report post Posted April 19, 2017 It's been reported by a couple guys on the owners club that the Cosworth box now contains a Mishimoto thermostat. Share this post Link to post Share on other sites
DanJ 374 Report post Posted April 19, 2017 Yeah they're the same now, James from Amber Performance (Mishimoto distributor) mentioned it at one of the MK meets earlier this year. Share this post Link to post Share on other sites
Steeps 294 Report post Posted April 19, 2017 It was stamped Mishimoto, but I don't think the new ones are same specification as the original Mishimoto thermostat that were having issues. Cosworth were in the process of changing suppliers so I am assuming it will be a new version manufactured by Mishimoto. Share this post Link to post Share on other sites
Lauren 2259 Report post Posted April 19, 2017 You don't need it. Seriously don't worry about it. I've did a track day at Donington in 2013, it was 37C. No problem with water temps, oil temps was a bit more tricky. Also done the Alps clockwise and anti-clockwise with temps in the mid 30's. Again no issue. Near Tokyo in a hired GT86 the temperature hit 49C. Again no problem. Share this post Link to post Share on other sites
will300 812 Report post Posted April 19, 2017 I've got one fitted and I agree it's a waste of money. The stock one is efficient enough and less likely to fail. 1 surrey86 reacted to this Share this post Link to post Share on other sites
surrey86 352 Report post Posted April 19, 2017 Anecdotally the Oem one never seems to fail whereas there's been multiple reports of the old Cosworth item going. The Mishimoto item has a lifetime warranty so you'd be a nutter to pay twice as much for the same part with less warranty. It does seem to offer minimal benefit in order to justify adding an extra potential failure point on the car. If you're doing tourist laps of the ring temperatures probably won't be an issue as usual practice is to stop after 11 minutes or so to chat shit about how "I woulda beat 10 mins apart from that pesky GT3 holding me up on the carousel" before doing another lap. Share this post Link to post Share on other sites
Ade 517 Report post Posted April 20, 2017 I've only heard of the one cosworth one going on a chap on the other forum (bought it used). His wasnt closing so engine was never getting up to temp. Ive heard of quite a few of the Mishi going, and when they go it stays closed which means you can overheat the engine. I wrote a lengthy post on the other forum about them. Someone at cosworth made a cockup and didnt pay the thermostat manufacturer. With a 6 month lead time the management made the cleaver silly decision to use the mishimoto stat. Its design was changed slightly since the failed units. When they get proper units back in a few months they will be supplying them with new kit again. I must stress it was not something the lead engineer Matt@Cosworth agreed with doing. Regarding NEEDING a stat. It a bit like an air filter. OEM one is fine but you still change it out for a few HP. Cosworth measured a 2-3hp improvement over stock (N/A power) but it needs to be tuned. As DanJ said its because they can run a little more ignition advance. With the Cosworth tune, it takes this into account. The reason the stock runs so hot is because you get a little better fuel economy. I had the manifold off when I was fitting the Moroso (please dont ever buy one of these) so it was a fairly quick job for me to fit it then. I dont think I would bother just to fit the Tstat, but if you are taking the manifold off you might as well. 1 surrey86 reacted to this Share this post Link to post Share on other sites
Benoxen 0 Report post Posted January 25, 2019 Just reading this now after installing the Mishimoto thermostat i got out of a Cosworth box this afternoon....only time will tell... Share this post Link to post Share on other sites
Lucas 244 Report post Posted January 25, 2019 8 hours ago, Benoxen said: Just reading this now after installing the Mishimoto thermostat i got out of a Cosworth box this afternoon....only time will tell... It's exactly same thing. Cosworth just charge more. Share this post Link to post Share on other sites
