My admittedly lacking understanding in this area says that lowering the compression ratio was sort of an "old tech" way of preventing knock when going big on boost. Like, when your only fuel control was a rising rate fuel pressure regulator...
But with more modern fuel and spark control, you probably don't want to lower compression at all. I think focusing on e85 (injectors/pump/tune) and leaving the pistons alone would probably net you much better gains.
For injectors, I have no idea if these will work for you, but let me shamelessly plug this for sale thread:
In reply to Robbie (Forum Supporter) :
It's getting harder and harder to ignore your ad when you keep pasting it all over the forum.
In reply to Robbie (Forum Supporter) :
Agreed- lower CR for boost is definitely old school. In a perfect world I wouldn't want to change the CR, but if I want to go over 200hp I need to upgrade the rods. One upgrade path is 7.3 CR and $200 against my budget, and the other is 9.5 CR and closer to $500 against my budget (which I probably don't have). I also have most of the parts for the $200 option.
In the context of the challenge I don't see the 7.3CR making my car 300$ slower. Three benjamins a long way at the challenge.
I love a good shameless plug, but already have injectors! That makeshifter is almost trophy worthy though.
Here goes a bunch pause while I nerd out...
You don't "need" to upgrade rods at 200hp on a D you need to not have a big low RPM torque spike and detonation at the same time. All the d16s with 16g's bolted to crappy manifolds or Edelbrock turbo kits that look like a hand grenade went off inside them are victims of that specific phenomenon. A Conservative boost curve or a really big turbo will keep you out of the woods. For example, just playing around here that beat to death D15 that was in the CRX the year I met you lived through a post-challenge installation of a GT35, street tuning and like a month of really fun runs around the farm roads easily 300hp it did finally bend a rod. D series rods are not strong but they're not quite as weak as everyone says.
Plenty of people monkey around with stock B rods which yes are much stronger if you have an engine machinist buddy getting B16 rods to fit a D is surprisingly easy.
Talking about Eagles and Vitaras yes 7:1 compression can work and can make mega power. An easy way to think about it is you're narrowing one window to expand another. Low compression makes for a big tuning window that's pretty hard to mess up however your power band is likely to be narrower yes you can make up for that with engine speed but let's be real we're talking about Ds 8000 is around the time where things start to get weird.
Where do we find compression... Well longer rods or correctly shaped pistons are ideal. It's relatively inexpensive to have lock ring grooves cut into the stock pistons where a set up like that gives up the ghost I don't know but keep in mind there's nothing special or strong about vitaras. Longer rods are a nonstarter for challenge money and you'd exacerbate one of the larger D series problems in doing so.
Let's mill. Let's mill a lot. If we start with a Y8 head (cheapest "good" d series head) and a Z6 block/crank (oiling) all we have to do is take .020 of the block and .060 off the head (you'll likely end up using a D15 belt or B16 water pump gear) we arrive at 10:1 compression assuming a 28cc chamber (stock Y8 roughly 32.8 cc this amount of milling usually results in a 28ish cc chamber)
$100 of machine work to allow something like a T3/T4 50 trim to really come to the party is totally worth it.
What sort of power do you want to make? How are you tuning again?
In reply to Byrneon27 :
This is good nerding.
I'm aiming for 300 hp. It's mostly a WAG of what I think I can build, safely tune, and get through the challenge with. Tuning will probably be on the street-if I get cocky I'll play with some of the virtual dynos to see if I can improve the timing. Having a big tuning window sounds pretty nice
I got the H-beams for 80$ and I'm pretty sure I can trade this neuspeed front sway bar and some small stuff for the vitaras-but a machine shop isn't likely to want to make that trade for the circlip machining.
The milling idea is something that I need to look at. The next step for the d16a6 that I have in there is to pull the engine and have the block decked, so it's already going to the machine shop. Not sure how much the milling would be, but I was quoted 120 to make sure the block was flat.
If I end up going with the 7.3 CR I'll try to move the curve a little bit lower with an adjustable cam gear and definitely want to try an EBC as well. At the end of the day, I don't think this engine will be below 3000 RPM in competition, so I just can't see a reason to make tuning more difficult. Won't the power bands once in boost be roughly similar if we're at 7.3 CR vs. 9 CR?
Proposed setup-let me know if you see anything that would prevent 300hp (or break first after I'm there):
Just posted this to the for sale forum. I'm trying to buy this and then sell the shell to max out my recoup. If anybody is interested in buying the shell (and possibly my current drivetrain!), let me know.
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https://www.facebook.com/marketplace/item/687350381881821
I'm going to see this on Sunday and hope to buy it, pull the engine/transmission/ECU/Obd0-1 Jumpers/battery and then sell the shell for $550 (max recoup for my challenge budget).
If anybody is interested in buying the shell (same as pictured, minus the stuff listed above), let me know. If I buy this then in January I will also have a complete (but sometimes overheating!) d16a6 engine/trans/ebay turbo/obd0 ECU setup that I can sell separately for FMV. FMV is likely between $600-$800, but we'll have to see what the forum says.
If you're in the Tampa/Naples/Miami area, and want to join the challenge in 2021, here is your easy button!
Mark me down for the cluster and interior panels if you pick that hatch up.
What can you comfortably spend on a starting from zero engine/trans/turbo kit/electronics set up?
Thanks! I'm hoping to just sell the whole shell, but if I part it out you'll get first crack.
I just added it up, looks like I'm $738 against budget for the engine/trans/turbo/ECU.
| D16A6 w/5spd Transmission and Axles | $ 150.00 |
| D16A6 Gasket/Bearing Kit | $ 79.95 |
| ECU | $ 39.00 |
| Chip from Tuning Kit | $ 16.00 |
| Intake Manifold | $ 20.00 |
| Axle Seals | $ 22.00 |
| Bolts for Water Pump | $ 1.50 |
| Cylinder Dowel Pin | $ 8.75 |
| Head Refinishing and Clean | $ 96.30 |
| Throttle Body Gasket | $ 4.79 |
| Used Turbo, w/injectors | $ 300.00 |
What's the engine in that donor you're looking at?
I'm not super familiar with Honda yet but am curious because I think itd be a good fit for powering my x1/9.
If the valve cover is correct to the engine it's a D16z6 92-95 Civic SI and EX and Del Sol si
What Bryneon27 said. This whole deal is almost entirely because of challenge math. If I can haggle this guy down to 600, pull the drivetrain and ECU, and sell the shell for $550 (maxing out my recoup) I can pull another $200 or so back out of the budget. For challenge purposes my current engine and the one in the swap are identical. Both heads flow well, neither have oiling problems like later versions. Yeah, the Z6 has vtec but it doesnt matter when you're running a turbo anyhow.
If you're getting into d-series engines the d16a6 (currently in Crusty) and the d16z6 (currently in the shell-i-don't-yet-own-but-am-trying-to-sell) are the ones to get. IMHO D16 is better than B16 because every honda kid thinks that the b-series is still the engine to have, and it drives prices up. Looks like k-swaps are an option for you as well, I know Bryneon27 is going that direction for his next challenge build.
Edit: One last thing. The reason NOT to do d-series is the lack of LSD options. Yes, there are aftermarket pieces out there, but they are expensive and I've never actually seen one on the used market. I think that's not the case for the b-series, and maybe k as well.
I'm a vtec fan turbo or not you can argue the A6 head flows a smidge better. Ultimately it doesn't matter that much.
As to the D, B, K debate you have to remember one was designed each in the 80s, 90s, and 00s one designed purely for economy, one purely for performance, the last to replace both.
Ds are small, light, and cheap surprisingly big power is just a gt35 away.
Bs are iconic, I recently bought an unmolested Integra gsr and while difficult to describe why it's just perfect and the vtec crossover just makes the best noise even from the stock exhaust. There's a personal connection to this car that might be clouding my judgement.
Ks well Ks are Ks big, heavy, relatively expensive (if you buy a "good" one) and kinda soulless but man do they make power.
It's worth remembering if you're planning to adapt a Honda engine to a non Honda trans D's, B's, Fs, and Hs spin the wrong way. Ks easily go to Mazda, BMW, and Toyota gearboxes with easily available parts.
Now let's build some cheap nasty power...
D16z6... Sorry I'm stubborn $150
Eagles $80
Machine stock pistons for locks $100 (way too much)
Open up ring gaps, reuse bearings and seals let that bastard leak it's the challenge. If you're smart/scared pony up the $28 for a Felpro head gasket. Port the oil passages in the block and pump.
Ebay ramhorn $115
Ebay 50 trim $100
Ebay 38mm gate $40
Two bosch recirc valves (steal them from the upull)
Stock black srt4 injectors $40 (need resistor box)
As far as tuning if you can find someone good at the chip tuning cool, I'd probably try to find an s300 or neptune unit cheap but that's going to take some time.
You'll be out of injector around 320hp
Chinese 4pad unsprung clutches do work well enough. Open diff and general D drivetrain part strength is going to be a limiting factor
Engine pull!
Spent part of the weekend pulling the engine and getting it on a stand. Got the engine out the bottom, winched it onto a pickup to go home, and then used a 4x4 to get it to the right height for the engine stand. Logistics, and gravity, continue to be my worst enemy with this thing.
Need to call engine shops tomorrow, 99% sure I'm going to roll with the 7:1 compression and just turn up the boost.
Engine is disassembled and cleaned.
Spent the AM checking the bores with Harbour Freight bore gages and digital caliper. Everything looks honkey-dory so it's off to machinist this week to get the head and block surfaced and ready for assembly-really happy I don't have to spend the extra $125 to get the bores done.
Bought a set of Vitara pistons (120$) and gasket set (already included in budget from 2019). Also put the old pistons/rods on ebay-might get some recoup yet.
DIY Engine Building!
Block and head are back from getting decked. To fit the larger rods I need to notch out part of the engine block at the bottom of the cylinders, so I went after it with a die grinder. After that I hit the cylinders with a dingle ball hone, scrubbed everything down to get the metal shavings out and then coated the cylinders with oil to keep the rust off.
After weighing the rods it looks like there is a difference of about 10 grams between a couple of them. These are no-name copies of branded copies of Manly rods that I bought second hand, so I'm not exactly shocked.
At first I thought I could just remove material from anywhere on the rod, but it looks like the correct way to balance conrods is to balance the each end separately using a jig. This is because there are two types of force applied to the conrod-the big end rotates around the crank and the rest of it goes up and down, all at the same time. Here is my DIY jig:
Right now I can take 5 measurements of the same rod and have them within a gram of each other. I'm going to try to get that down to .5g variance, but we'll see. The pistons were already within .5g, so I won't need to futz with them.
I admire your deep dive in to building your own engine as I say berk it with a $200 engine of unknown history.
^ yeah. Awesome!
Back on this E36 M3. The larger rods also hit on the block girdle so it got massaged with the die grinder as well. I forgot to mention the pistons needed to be ground out a bit to fit these rods as well. There are definitely higher quality and better fitting rods I could have used, but none that I could buy for 80$.
Checked the specs on the crank, everything looks good so a new set of standard bearings went in. No clue how many miles on this engine, but it was sold to us as running on 3 cylinders and having over 200k miles. At about .038 it's barely out of the "came off the assembly line" range and well under the .05 wear tolerances. I guess Honda got the oiling right on the early d16's.
And everything got torqued down. Oil pickup tube was filthy as well-amazed that I had good oil pressure when I was running it last season. Standard oil pump is fine on these, so back it went, along with the rear main seal.
Head should go on this week, might get it back into the CRX next weekend.
In reply to CrustyRedXpress :
So what's the HP goal?
I'm hoping for 300hp or bust.
Hoping for 300, but realizing bust is a possibility =P
What @Bryneon27 said above is on point-I'll run out of injector at about 300.
More progress:
Block, oil pump, main seal, oil pan and head all together and torqued down. Timing belt went on after this on and mechanical timing set. Wish the block was cleaner but getting it dipped wasn't in the budget this year.
Yo dog, I heard you like paint pens! I use 'em because I can only do an hour or so in the garage at a time and it helps me remember what steps I've already completed.
Lots of time spent with various taps and dies cleaning up dirty or stripped threads. The m10 x1.25 hole in the transmission mount was shot, so it got drilled out and is now a m12x1.25. C'est la vie, c'est la guerre.
At some point I'll become an adult and get the correct tool for holding flywheels in place. I'm ashamed to say this screwdriver has been doing the job for 20 years now. Oh god I'm old.
First time using an engine hoist-absolutely amazing. I imagine this is what it feels like having your own lift in the garage.
That's about where things are now. Engine is in and all the various systems are getting bolted back together. The cheap turbo setup that I bought early in the year is going to need more fabrication work to fit so I'll need to get serious about learning brazing and welding.
Next get a load leveler and blow your mind again!
In reply to Robbie (Forum Supporter) :
Haha! I almost got one but am trying to keep the tool budget down. My wife is convinced that the Challenge is the art of spending 3 thousand dollars on a 2 thousand dollar car that I'll eventually sell for a grand. She's not completely wrong.
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