John B

I just tested my Caterham with the 327 hp 2.4L engine. Holy crap, I've created a monster!!! It's just explosive. I Can't wait to bring it to NJMP next weekend.

Wow Jay, That's a bummer! I think you're on the right track with a compression test. A leakdown test and borescope inspection could reveal a valve issue. Other ideas: Could be a cam position sensor. That would make it put fuel in at the wrong time. I've had that happen on another car. It ran rough. Check spark on #4 cylinder. Maybe a bad coil? Good luck!

Are ZZR's better on track than Hoosier R7's, or A7's? I think I had A7's last time and they seemed to be holding up relatively well.

I think we're going to need to do a full fledged intervention at NJMP. We can't let this fleeting moment of sanity gain traction.

Seb, Best of luck with the new job! My Favorite track in the country is not far from MI. Road America at Elkhart Lake, WI. 4.5 miles of bliss!

Simon, that looks great and should be a blast! I think you'll need a Cowboy makeover to pull off that Montana plate though

Thanks Croc. it held up with the 2272 hp MZR. i’ll be careful with it. but... Just in case, what’s a good Plan B?

I think the C.R. is 12:1 but am re-checking with Hasselgren. The 2.3 Cosworth Duratecs used in the Swift 016 Formula Atlantic racecars spend most of their life at 8,900 rpm and get get rebuilt at 15 hours (1,500 miles). This engine will probably have an average rpm of 3,500 throughout it's life with brief spurts up to 8,000 on the street. But it will get a few hours of 7,000-8,000 at track days. I'll log track time and shoot for a rebuild after 20 track hours (about 10 track days). I'm not sure what the trans is, but I know it's not a Sadev. It's a 5-speed of some type. The car is a 2003 SV that originally had a 2.3 Duratec. The Diff could be a weak spot as well...

It was dyno’ed on 93 octane pump gas

It looks to me like it "wants" to live between 7,500 and 8,500, where the power stays about flat at max. But... given that I'd rather not turn this one into a coffee table, I'll keep it below 8,000.

Final pull: 325 hp @ 8.100 244 tq @ 5,700

Correct Croc, it was actually my son that made it go boom. Both times actually... This one will rev to 8,500, but I’ll mostly keep it below 8.

I’m in!

Well it’s been about a year and a half since I blew a hole in the block of the 2.5L MZR engine in my SV at a NJMP track day late in the summer of 2019. Covid induced delays at my engine builder Hasselgren Engineering slowed things down quite a bit. I’ve suffered a fairly severe case of Caterham withdrawal as a result. My wife and I are on a trip out to Santa Clara, CA to visit our son and we drove around the Bay area doing some hikes and stopped for lunch in Berkeley, where Hasselgren’s shop happens to be. Paul Hasselgren has been building the race engines in the Formula Atlantics my son and I have been racing for quite a few years so I naturally wanted to pop in and pay a visit. It was pretty much pure coincidence that this happened to be the day my engine was on the dyno. Paul has done quite a bit of development on it and we went back from the 2.5L stroker crank that failed in favor of a Billet and balanced 2.3L crank. The engine is basically a short stroke 2.5 MZR with a bigger bore and a balanced billet crank from a Cosworth Duratec The whole front end of the engine has been redesigned to run a belt drive for the cams. I was hoping to get a little more power than my previous 2.5 MZR with this higher revving configuration, but I was quite surprised by the result. 312 hp at 7,500 and still climbing. 241 peak torque @ 5,900. Paul says he’s not done yet. He thinks he can get 320 out of it, which will be limited by the barrel throttle dimensions. A redesigned barrel throttle can unlock even more. Paul cautioned this one will hit hard. Good! I can’t wait 😛

For me personally a lot depends on the intended use. Generally, these are my criteria for cycling tires. Daily Driver used for routine local errands: Black Round Tread remains Hold air High performance street car: four above plus the 6-year life. Race car: 6 heat cycles.

Congratulations Craig! Well deserved

Croc - Make sure you use a billet or forged crank in the 2.5L Duratec

I just got up to speed. Your new car sounds awesome Croc! One thing, and I'm speaking from experience here, make sure you use a forged or billet crank! You'll have to have it custom made. That's basically the same engine I had in my Cat when we blew it up last year but engine builder figured a cast 2.5L crank from a Ford Ranger pickup would be ok because it's a street car. - NOT! How was the event? I need posts and pics

Oh Ohh! What did Croc get? I think we're squeezing all we can out of this NA Cosworth Duratec

I still don't have my engine back from my builder in CA :toetap05: So I'm not going to make this one. Have fun and stay safe! Best to all, John

It's touch and go if my engine will be ready, but I optimistically signed up :driving:

The thought has crossed my mind...

Wish I was there. My engine's still in CA.

Hi Croc - I'm not really sure what the HP will be, we're breaking new ground here. For a guess, it's almost the same displacement as the 2.5 which made 200 lb-ft of torque at 7,200 and 274 hp. If we can make maybe 180 lb-ft but about 1,000 rpm higher that could get us over 280 HP. We'll see soon. I'll keep you posted.

I kind of forgot the Cosworth 2.3 Duratec revved to 8,800. That's Formula 1 and Winston Cup piston speeds. (27.5 meters per second avg, 43.3 max). The short stroke engine equivalent would be close to 9,100 but I don't think I'll push it that hard. We'll see what the torque and HP curves look like.