Horsepower from your Z?

[Ron Earp]

I know, a "secretive" question for sure, but an interesting one.

I run a 260Z that I'm getting ready to do a couple of things to in order to free up some power, or at least improve breathing. As some of you know I run some crappy air filters that came with the car and I plan to build a larger panel type filter to get rid of those. A few folks have pointed out that should be worth a couple of ponies.

I also plan to do something with my exhaust to improve flow. I am running a side exit exhaust with a muffler and it is fairly quiet. Do you Z guys use mufflers at all? I was thinking of a straight pipe that went back to the axles and turned down, no muffler. Will I still be able to pass sound?

I still haven't dynoed the 260Z yet but I really need to for tuning purposes and to simply see where it is at on the horsepower scale. Any of you guys have some dyno results from your Z?

[Tom Donnelly]

Ron,

I ran 6 into 2 and then a y collector to a straight pipe that ran out to the right side just ahead of the rear tire. No muffler, passed sound control because sound control was usually on the left side, not the right. Jim Thompson setup. 172hp Sunbelt motor.

My new car has a John Williams style setup, similar header, straight back and exits thru a muffler just behind the driver, with a pipe pointing down. No dyno tests yet. Although it snags on a trailer every time and I have an exhaust leak I need to fix. So I'm not sure I really like it.

Like everyone else, I usually look to Keith (Katman) for the best answer. He had a post a while back on exhaust systems. The one on Chet's ARRC winning car had an interesting exhaust system. But if Keith is around he could better tell the story.

Tom

[lateapex911]

Katman probably did 100 dyno runs with 12 headers and other combos...LOL. His stuff was pretty thorough. Tom was that 172 at the wheels? The hubs? or the flywheel?

[Tom Donnelly]

Jake,
That was 172 at the flywheel. The motor was built in 1999. I've heard of much higher numbers later on. Chet won one of the ARRC's with hp around thereabouts and turned 1.41 / 1.42's at Road Atlanta. Again, Keith would know. I didn't have a great motor, but it lasted and was good for enduros. And you're right, they did their homework and tested a good bit.
More hp = more money. And real dyno testing isn't cheap.
Tom

[Ron Earp]

I remember that too Tom. Seems they won with less hp than some of the best Z's are making nowadays, 175 rwhp and a bit more. But, I do remember a post from Katman that said they got to those power levels at the end of the program too.

I'm interested in seeing what the various flavors of Zs make. I don't think anyone has dynoed a 260Z on a Dynojet yet, but I'll be posting stuff up once we do. I'm not too ashamed to let folks see what I make!

Best,
Ron

[pballance]

Hey Ron, If I had a clue on how little HP I was getting I would post it up.

If the motor survives me and Roebling for one more event I will be putting it on a dyno the next weekend. I will then have a clue (or maybe not depending on who you listen to).

FWIW, I have a Datsun Comp header into a single pipe with a muffler in the OEM location. Exit is at the OEM location. I think I was measured at 78 db's at Roebling last year. I am sure I am giving up some hp. Friends at the track said they couldn't hear me coming and were amazed at how quiet my car was, especially when compared to the rotaries. Katman drove my car early last year and commented about how quiet it was. FWIW, my RX8 turned 93 db with a Magnaflow catback.

I will start the upgrade and measurement of hp changes after school. My order of change will be intake : get rid of the K&N style air filters and build heat shield cold air intake out of OEM air filter backing plate and use a Pipercross filter. Yeah I know I need to be careful here but it will not be a "ram" induction and it will be legal


Then it will be exhaust and I am not sure what I will do there but try to find an exit other than under my butt! I am hoping Keith will tell us all how to finish the exhaust as somewhere I already have a copy of his posts regarding headers.

[kthomas]

I'm a big fan of quiet for a few reasons that don't have anything to do with performance. First, like solidly mounted engines, loud pipes tend to loosen and crack things. Second, the in car video usually comes out better. Third, it spooks your competitors when you pass them. Color me weird. Oh, and I've also had a win taken away because we exceeded sound. Another brilliantly written appeal with 8x10 color glossies and affidavits from acoustic engineers that somehow was "unfounded". %$@#*.

Best sounding exhaust for a Z is dual megaphones. Schuweeet! Unfortunately also about 108db and 10hp less than a single.

The last iteration of Chet's exhaust aft of the headers was a simple 2-1/2 that transitioned to an oval and exited in front of the right rear wheel. Simple, light, weight to the right. Not particularly quiet. If we could afford a Borla I would have liked to have put one in line. I believe the Stepp car and the Williams car both had an oval Borla in the tranny tunnel with 3" pipe that ended just in front of the diff, turned down. This sounds pretty good, doesn't hurt performance, but does have clearance problems. Plus, I ain't a big fan of exhaust fumes under my driver, although it does help blow the track clean.

The only thing I don't like about the stock setup is the extra weight and the location, left. The Williams setup is theoretically about the right length (when you look at where the open pipe needs to be for proper wave reflection), however, we've shown that what happens after the header doesn't have too big an effect on performance as long as it's at least 2-1/2 dia. FYI, a Dynomax Super Turbo, 2-1/2 in and out, only costs you about 1 hp at the wheels. The biggest problem with mufflers is they take up space and and have weight. Not a lot of space under a Z other than the stock location. If I ran a lot of enduro's I would definitely run a stock arrangement, but because of the length I'd proly transition the 2-1/2 to 2-3/4 at the front of the diff.

I think in 1999 we came in second at the ARRC. That exhaust system had a home made long oval muffler with a big open chamber at the front, then a straight thru bullet muffler type section, and then another open section at the back. I was trying to get a sound wave reflected back to the exhaust valve at the right time. On the engine dyno after the race it made a whopping 165 hp. So much for theory. However, it does show you can be competitive without killer hp if the rest of your program is sound. Sunbelt's biggest number for an ITS Z engine was 208 hp. We won the next 2 ARRC's with less than 198. I think 185 is pretty dang stout, and doable. I don't think we'll ever see 208 again.

But to answer Ron's original question with a question, what are your headers? We have to start there. PM me and I'll scan in some dyno runs and send them to you next week. You can post them here.

[Ron Earp]

I On the engine dyno after the race it made a whopping 165 hp. So much for theory. However, it does show you can be competitive without killer hp if the rest of your program is sound. Sunbelt's biggest number for an ITS Z engine was 208 hp. We won the next 2 ARRC's with less than 198. I think 185 is pretty dang stout, and doable. I don't think we'll ever see 208 again.

So are all of these numbers engine dyno numbers?

My exhaust is about what you describe on Chet's car - 2.5" mandrel bent tubes,bullet muffler (but not extremely high quality), and a side exit exhaust. My muffler location isn't ideal, it is about under your butt in the tunnel area and right after that we have a 90 degree mandrel bend out to the passenger side. Sort of cuts down on ground clearance a bit, but on the other hand the guy that did it for me worked extremely hard to make it fit well and it isn't bad.

My header is that one that is shown on my blowed up motor thread some months back, here:




I'll shoot you a PM here is a few.

Thanks!
Ron

[Ron Earp]

Keith,

Your profile won't allow PMs or emails, as far as I can tell. My email is [email protected] though and you can definitely send me stuff there, same for you too Chuck.

Best,
Ron

[kthomas]

Hmm, dunno why the PM's don't work, can't see anything in my profile that prohibits that. I'll drop you a note tomorrow.

All my dyno numbers are engine dyno, SAE east coast (i.e. real calibrated SAE). What's the diameter of the primaries and collectors on those headers?

[ddewhurst]

Guys, looking for a 1.187 inch diameter three hole adjustable sway bar for the front of a 240Z car.

I am told a guy by the name of Sayner from FL makes/has them for sale. Anyone have some info, have a bar or have a contact for Sayner?

Looking at doing a Speedway Engineering but it would be simpler if someone had a contact for a 1.187 inch diameter bar.

Thanks
David

[Ron Earp]

Too big I think Keith. Greater than 1.5", probably around 1 5/8s. They go into two collectors each about 1.75", then merge into a 2.5" single.

On the other hand, it has a bit more displacement and a larger exhaust valve than a 240z. what do you think?

R

[Tom Donnelly]

David,
Both my cars had speedway bars. (Didn't mean to rhyme there, but did anyway).


Ron,
My Z has the Borla like Keith describes. And it scrapes every time on and off the trailer. There's some posts about headers around here from before.
Tom

[mom'sZ]

Ron:
In that picture of your engine, where did you get that pan? Custom made? Sorry for thread jack

[x-ring]

I'm interested in the answer to that too, Ron. After my little, um, episode last fall I need a new pan.

http://i237.photobucket.com/albums/f...r/IMG_0099.jpg

[Parrish57]

The pan in Ron's picture looks like a Nismo pan. They work great, but can have clearance problems depending on the header.

Ty... It looks like you were using an Arizona Z pan when you had your "episode". What did the autopsy determine was the cause of death? I've started using the Arizona Z pan myself, it's cheaper than the Nismo pan by about half.

[JeffYoung]

Yes, it is a bitch getting the header and the pan in the car. Hardest thing about engine removal/reinstall for us (on the NISMO).

[mom'sZ]

Man.... that picture of Ty's motor was not what I needed to see first thing in the morning. Scary... how did that happen? If I missed the story, sorry.
I'm using the arizona Zcar pan as well. My engine builder told me it bolted up perfect, no holes needed so much as filed or reamed to bolt up. Further more, having pulled the engine in and out twice now since installing it and tranny R&I, I can say it fits well as far as clearing the core support ect during engine swaps. Header (MSA cheapy) also clears it well. Ground clearance is same as stock. Adds 1 quart capacity and has the nifty trap doors like the nismo piece. It's heavy
I thought the nismo one was cast as well, that pan on Ron's motor looks like sheet aluminum. My guy tried to get the Nismo pan but said the pan was available but the oickup was back ordered for months. The Arizona Zcar one uses the stock pickup.

[Ron Earp]

The only reason I'm using the NISMO is that it came with the car. It does create some issues on install. Actually the worst issue is that it will sit on the steering rack with some engine mounts and needs a couple of shims to get up off of it. That actually caused our steering issue I wrote about some months ago.

On the other hand, like the AZ pan it is well constructed with trap doors and so on. Capacity is 8 qts it look like, so quite a bit of oil on an oil change. The NISMO isn't cast as far as I know. It seems to be a cut and welded sheet assembly, or, at least mine has some of that on the bottom. Could be mine is some bastardized NISMO pan as I've never seen any pan but this one.

[x-ring]

Ty... It looks like you were using an Arizona Z pan when you had your "episode". What did the autopsy determine was the cause of death? I've started using the Arizona Z pan myself, it's cheaper than the Nismo pan by about half.

Actually that pan was from MSA. The Arizona Z pan was out of stock when I needed one (in 2003 I think). I'll be going with the Arizona Z pan now. I don't think it's any better than the MSA pan, or any worse, but it looks nicer and it is (or was anyway) $100 cheaper.

As for the engine, the failure was that the crank broke down around the last con-rod at about 6500 rpm. The guy behind me said the fireball from the oil was pretty spectacular. Wish he had video. I have another photo around here somewhere showing shrapnel holes entering the RH side footwell. I didn't realize it until I was pulling the transmission (which also was trashed), but one of them is maybe 0.5" from a fuel line. A *little* sobering.

The cause? Well, it's hard to tell for sure, but the three main cap bolts in the middle were tight The ones on the front two came loose with just a little bump on the wrench. Maybe a phone call during engine assembly? Who knows, but the damn thing only had about six hours on it. Suffice to say I've found a new engine builder. It's a lot longer story than that; one that I don't care to relate right now (I still have several hours of work to crank out before I can call it a night). But if anyone is really interested I'll be happy to share later.