MyE28.com

I just wanted to introduce myself to the new board with some info about my e28. I look forward to contributing to these forums and I hope I can be good for something to some of you. Anyway, about the car.

The latest project started as a 1988 528e. Produced in 4/87, it was a factory super eta, with the fancy harness and pistons and a good three years less use than my last car. The engine and automatic transmission came out right away. The engine got a down to the block rebuild, and was reinstalled with the manual trans from my old car. The goal was a 250 or 300 hp turbo engine, so it was all stock except for the basic e to i conversion, with a new 325i cam and valvetrain and the 325i intake.

For the turbo setup it got an e34 524td non egr manifold. This required significant modification just to fit over the m20 head studs, and it got some more grinding to open up the insides to better suit its new application. This particular manifold has a T25 flange, so I chose a Garrett GT2560R watercooled, ball bearing turbo. At my altitude and assuming some general engine specifications, its good for over 300 hp at the highest boost levels and is well clear from the surge in absolutely all conditions. That just happens to be the same turbo the Nissan S15 Skyline comes with, so they're also very easy to come by.

I managed to plumb a FMIC under the front bumper and back up into the stock AFM mount on the passengers side of the engine. For fuel enrichment I chose a Cartech RRFPR to work with the stock 325i injectors and a 2.5 bar standard fuel regulator. The exhaust is a single 2.5 inch mandrel bent, half galvanized backyard one-off job.

It all went together this last weekend, and with the exception of a few unforseen hangups, it went smoothly. The first drive this afternoon was invigorating to say the least. I dont have any boost gauge or AFR gauge hooked up yet, so I set the RRFPR for max enrichment. Though its likely running pig rich, it most definitely hauls. I'm looking forward to some more gauges and eventually a dyno run when its more precisely tuned. If I had to guess, I'd say 250HP at the flywheel. But when I get a dyno figure I'll see for sure.

Thats about it though. I'll see if I can come up with some pictures. Thanks for reading.

Pretty neat. Welcome to the board.

Now THAT would be an M20 worth boosting!

welcome

Good stuff! Sounds similar to what I want to do some time in the future.

Neat project. You need to be careful. Have you upgraded the fuel pump? The stock injectors will need 95psi to support more than 7/8psi effectively. You should upgrade to 24lbers.
Todd

I am concerned about fuel. Its got a brand new, but stock main pump. I have the RRFPR almost maxed out on the fuel pressure increase ratio, but I dont know what its really doing as far as fuel pressure. I dont have any other gauges hooked up, so I have no idea what its boosting to or what the AFR is under boost. I believe the WG is set to 10 PSI, so its probably making 12 up here at ~6k feet. Its a stock Nissan S15 Silvia turbo, so its doing whatever they do. I'll have to hook up a gauge and see.

I have a brand new set of 535 injectors I'm considering, but I'm hesitant to swap injectors because I'd hate to lose the off boost driveability. I dont have an o2 hooked up yet, so I'm not sure how it'd handle any upsizing. I'm still taking it pretty easy in general, as I'd hate to blow the new motor up. Thanks for the insight so far. I think I'll have to install some gauges and see whats actually going on. It runs very well, so I'm hoping I lucked out with the initial setup. That'd be a longshot.

turbodan wrote:

I have a brand new set of 535 injectors I'm considering, but I'm hesitant to swap injectors because I'd hate to lose the off boost driveability.

"off boost drivability"? No such thing with inj swaps. The 535i inj's are only 18lb injs. Get the 24lbs like Todd said.

RussC

Hmm. I just remember how the other cars I've swapped injectors on have behaved. Slightly smelly, jerky at the transition between engine braking and cruising. But none of those were turbo cars, so maybe I'll give it a try. The hard part will be to actually stop driving it. Its an incredible experience.

turbodan wrote:Hmm. I just remember how the other cars I've swapped injectors on have behaved. Slightly smelly, jerky at the transition between engine braking and cruising. But none of those were turbo cars, so maybe I'll give it a try. The hard part will be to actually stop driving it. Its an incredible experience.

Your describing a car that was not properly tuned for the inj size being used. Im not supprised.

RussC

Well, until I get some gauges, is there any way to tell if its detonating other than that sound? I dont hear it, its very smooth, and it doesn't blow smoke under boost, so I can only assume its running fine. If its not experiencing any problems I might just stick with the stock stuff. At least until I get an AFR meter and have the ability to really tune it for different injectors. I cant really pull and check the plugs with this manifold and turbo. Not without pulling the turbo and manifold. So thats out.

turbodan wrote: I cant really pull and check the plugs with this manifold and turbo. Not without pulling the turbo and manifold. So thats out.

Thats not good. This will cause you many, many hours additional work. Makes me even happier about my TCD s2 kit.

Even if you had a O2 sensor and gauge, how do you plan on tuning the ECU?

Here is what you can use for 80USD -

http://www.sdsefi.com/mmm.htm



It comes with a NB O2 sensor and will be a starting point for you. Wide Band O2 is what you want eventually.

I was looking at Split Second's ARM1, but thats pretty much the same thing. I dont really plan on tuning the ecu. I'm under the impression that I should be able to get away with just fuel enrichment. The idea is to tune it to run acceptably on a stock 325i chip, so ecu and chip failures down the road dont cause me so much trouble. I'm not looking to get every last bit out of this one, I just want it to run reliably. Can a guy do that without a custom chip?

Don't bother with a narrowband O2 setup for tuning. They're near worthless, especially for turbo tuning. The NB O2 sensor can only read accurate at or very close to stoichiometic, 14:1 or so. You'll want to be tuning to get your AFR around 12-12.5:1 on boost. At those kind of AFRs, the NB O2 will just read "Rich", which could be 13:1, could be 8:1. Doesn't tell you what you really want and need to know.

Innovate makes a nice WB O2 sensor and controller for ~$300 that goes into an extra bung on your exhaust (you can use the stock location if you're running open loop). It will also datalog for you from multiple input sources. It's an essential piece of equipment in the toolbox of any turbo tuner IMHO.

As for running with the bigger injectors, you probably can't just plug them in and have them work correctly. You'll need to re-adjust (tighten) the spring tension in your AFM to compensate. This is another time when the WB O2 is essential to have.

Todd's absolutely right about the fuel pump as well. It's been discovered through multiple failures that the Bosch fuel pump does not enjoy supplying very high pressure. It just won't last very long under that kind of demand. The more that is demanded of it in this regard, the shorter its lifespan will be. You will have fuel delivery issues with your current setup if it stays the way it is.

Jeremy

Cool. I wasn't sure if the current setup would last. Thats the information I was looking for. I really hate to mess with the spring tension because its always a trade off. It just doesnt seem to run quite right under light loads, and you lose response to sudden throttle applications like throttle blips. I cant stand that stuff. I'd rather reshape the inner curve of the AFM like I ended up doing on my last car. That worked very well, but I didn't have to tune for so much more flow. In any case, if thats what I need to do, I guess I'll do it. I've got a set of unidentified magenta topped injectors with yellow pintle caps in addition to the 535 injectors. Are those the 24lber's by chance?