Hitchhikkr

I briefly met Zac a few years ago when he was working for Rotorsports. Seems like a level headed guy, but Rotorsports as a business I dont much care for. I wont run my mouth or anything about that though.

Go with what your tuner is comfortable with, and what is known to work well. Bandwagons almost never pan out it seems.

2GeclipseRST

That's why he left. However, i have no complaints with my engine they rebuilt. I've heard mixed things about rotorsports but as far as what people say about zac, haven't heard ---- in the negative. I can't wait til he comes down here to pageland to tear the rustang rednecks a new ------- in the 1/8th mile. I enjoy going to the dragstrip when the imports come down. ALOT of bruised egos from "them ------- jap cars".

You local?

Hitchhikkr

There are quite a few NC/SC HMT'ers.

Im in Asheville.

Aaron Cake

And I'm sure everyone will give you a different answer. Hence my post to follow...


To me, stuff like this seems weird. Why would someone blow an engine "for fun"? In blowing an engine, it's likely that a god rotor, good housing, and possibly a good turbo are damaged. I don't see the point and I would tend to question anyone who would blow up an engine "for fun".

Building a 400HP engine with a stock ECU and an S-AFC is a recipe for disaster. At WOT it's probably fine, but where it will tend to blow is around 3800 RPM when the secondary injectors stage. With the stock ECU, no matter what piggback you use (aside from an AIC), you'll end up with a lean spot at 3800 RPM. And that's where it will pop with an upgraded turbo.

I'm not familiar with Holsets but was able to find a bit of info on the HX35 via some searching. Based on the compressor map, it looks similar to the GT35R. So we can make a few assumptions. One of those is that it will put down 350HP with a sane level of boost (15 PSI). However all the hotsides on the HX35 look to be small T3 sized housings. If this is the case, and there are no larger housing available, the minimum size you will want to run is 1.0 or larger. T3 stuff is very small for a 4 port 13B, and very, very small for a 6 port 13B. I suspect that if you don't have a good wastegate setup, you will have issues with boost creep.

First, that's not enough fuel. I'm not familiar with the RTek as I don't believe in "standalones" that use the existing wiring harness. I've seen a number of cars blown with early RTeks due to wiring problems and spotty timing control. However from what I understand, the new RTeks allow full timing control and will allow you to run different sized injectors. Thus, you don't have to mess with the CAS (which retards the entire operation of the engine, not just timing) and you can run a more appropriately sized 720CC primary and 800-1000CC secondaries.

If the budget is a problem, then it's probably prudent to just wait until the budget is no longer a limitation. You don't have to spend a million dollars to have a good setup, but being able to spend the money where it is important (ie. engine management) is necessary.

Are you suggesting you are going to run that HX35 under 10 PSI? Why not go with a more appropriately sized turbo then?

Or just get a J-spec and swap the engine.

On a stock turbo and ECU, you should not have to bump the timing back and the S-AFC will do the job as well.

The Megasquirt is a good choice if you know enough about electronics to set it up. But if you don't know these things, then the installation will be a disaster and far more prone to noise then a Haltech ever could hope to be.

Tom-Guy

Having only been through one miracle engine, the only reliable 20 year old motor on the face of the planet, you know very little about what it's taken to determine the safe limits of engines. Where I am from we build cheap setups to destroy in the name of progress, and it is one of the ways I've determined most of the safe limits for power/octane are invalid. It takes a lot more than one engine to figure these things out.


If you looked at the inducer/exducer specs you'd realise it's a small trim big wheel compressor and sucks compared to GT35 on low boost operation. 12-15+ is the sweet spot on them as they require a larger PR.

If by small you mean "P-trim T04" size turbine wheel. Well, the housing AR is speculated to be .55-.70, which doesn't mean what everyone thinks it does as the turbine wheel is so big.

Aaron Cake

You seem to be under the impression that I've only tuned my own car, which is incorrect to assume. I've worked on enough RX-7s to have lost count at this point and tuned everything from bone stock 13B NAs, to 12As with ITBs, big bridgeports, 13Bs running the HT-18, GT35R, GT40R, TO4R, T4B, 60-1, 62-1 and a bunch I am probably forgetting. I've had my hands in more then a handful of RX-7s making 350-400 wheel HP and above, as well as some Supras (a Supra-Celica NA inline 6 on Megasquirt, a newer Supra single turbo on AEM which made 600 wheel HP), a few random 4 cylinders on Megasquirt (Turbo Daytona, 240SX) and a twin turbo Windsor V8 (uh, 350? 302? I don't know V8s...). I don't do my learning by blowing stuff up, but by not blowing stuff up.

It seems to be no wonder that someone who thinks a reliable rotary is a "miracle engine" would think that blowing stuff up on purpose is a good idea. Learning by failure is an important thing to do, but when the method of failure is known (S-AFC) and the end result is known (blown engine due to lean spot) then nothing will be learned and the only result will be a waste of good parts.

I know how to tune to avoid blowing stuff up, and indeed, have never blown any engine. In fact, the only people I know who blow rotary engines are those who attempt to bandaid improper tuning and use things like the S-AFC to make high power numbers.

I did, however, build one engine that was blown "out of the box". It was done late at night, around 2AM, with a lot of distractions and crappy petroleum jelly holding things in place. A corner seal fell into an intake port and we didn't notice until the engine mysteriously didn't have compression on one side. Oops. The seal went through a few cycles and trashed a rotor and housing.

Now that you mention it is a common practice to build cheap stuff and blow it up where you live, it starts to make sense to me why you had mentioned the amount of blown 13Bs in your area in our previous conversation. What blows up a rotary is well known and experimentation should not be needed to figure it out.

As I indicated, I could only find a compressor map and fully admitted that I know nothing about Holeset turbos. It was a mildly educated guess on my part as to what the turbo will do, and I mentioned this in my reply.

If it really is similar to the T04 P-trim and is a .70, then it's too small. .96 on a p-trim is the smallest you will want to use on a 13B and will give you turbo response basically like stock. Anything less will be a cork in the exhaust, leading to very high pre-turbine backpressure and EGTs, making it far easier to blow the engine especially on shaky management.

Tom-Guy

Ten years ago it was common knowledge that a B-series Honda engine couldn't handle more than "8 psi." Without people like me pushing limits (just not with other people's cars) people like you wouldn't be able to make mediochre power figures with reliability.

Don't throw AFCs in as why my line of reasoning is invalid. I don't tune with AFCs, and your insertion of AFC tuning is a logical red herring meant to confuse my point. Further, if the rotary was as reliable as you claim then you wouldn't be worried about conserving on good rebuildable rotors and housings. I can think of a dozen valid reasons to destroy an engine on a dyno, in order to learn things that simply don't exist in engineering texts or the common (or not so common) body of knowledge. If you can't, I really don't know what to say?


Stupid stuff happens to all of us, is a fact of life, but it has no bearing on the discussion at hand. Stop with the logical red herrings intended to obfuscate the discussion.


Listen, nobody, it is common practice to build cheap stuff that eats $60K+ cars and lasts for years, but when I want to mix pumpgas with accelerants and oxidizers to see what I can squeeze out of it I build a $250 D-series and take it to the limits, then inspect the wreckage for the cause of failure. Quit with the insinuations that I am stupid or inept, as it is another logical red herring meant to detract from my point without addressing it.


And I fed you the rest of the details you needed about it.


This is the only thing in your reply that had any tech in it, can you stick to stuff like this? Brass tacks how-to on any car is always welcome.

Larger cm^2 Holset housings are easily available off of other turbos, IIRC up to 22 cm^2 can be slapped on. Given the low price they command for having pretty low miles one might be good for a budget build, just requires a little more research. devast8r would be the first person I asked for details, then Jaymez at Diesel injection Service in Cincy.

Foowee

Jaymez is no longer with Diesel injection service... They recently moved, significantly increasing his commute. I'm sure I've got his digits somewhere if you really need to chew on his ear.

2GeclipseRST

To Aaron and jd, thanks for keeping it somewhat civil.

To aaron in particular:

Zac likes to play around and blow ---- up. If it's his, he'll play with it and see what happens. It's no problem for him to find motors. He's pretty hooked up and i'm sure as hard as he works that money isn't much of an issue in that department. Pretty much he was testing the limits with skeleton crew management and found them pretty quick. Said the motor lasted a few months so that's not as bad as if he popped it on the 2nd or 3rd dyno pull.

Aaron, what engine management do YOU suggest for me? Apexi Power fc? HKS F-con? Greddy e-manage? Help me out here. It makes sense to go ahead and get this out of the way since i do have upgrades planned and i know the stock afm and ecu has it's limitations. I know i can use an safc on a stock motor but the thing is, for how much those are, i'd rather buy something that's more worthwhile. Aic controllers are pretty pricey. I looked into one for my dsm when i wanted to go gt35r and build a long rod motor. Also wanted to be the first to have a destroked 420a (420a had both 2.0 and 2.4L variants). ---- hit the fan when i went over budget but the point is, i looked into them already and found better alternatives. Thanks for the info about the injector crossover. Had you not informed me, i wouldn't have known.

About the turbo, if you think that is too small (and i do listen to what you have to say above most) how do you feel about an hx40 variant? If so, which? 400hp on tap would be nice but i'd like to keep the boost sane at 300whp during spirited driving. It's been also 100% decided that we will pursue aux injection.

I do not want to do a turbo II swap. I did but the motor quality is always going to be questionable until i check it out when it arrives on a pallet at my doorstep. I know my six port is tip top. Rotorsports rebuilt it not to long ago. The shortblock itself and alot of the intake parts saw most of the labor. I know the alt is new, water pump and oil pump is new, thermal pellet is new, all seals are new, I think oem corner seals with rubber inserts were used, new oil control springs, oil rings, side seals, apex seals, side and apex seal springs......etc.... Not sure if that will cause a problem in the future but only time will tell. All i have is a recipt with rotorsports' name on it and a price. Most of the recipt is covered with soda....i hope it's soda anyway. I did find a pair of pantyhose under the drivers seat.....

Tom-Guy

Yah, well, we may not see eye to eye on some things but he knows his rotaries. If people are asking rotary questions he needs to stick around and point them in the right direction.