I have finished the suspension and body work on my EF and I am looking to start building the motor or swap a k series in it. I have some questions in mind that I hope you guys can help me out on.

1. How reliable is a 400whp z6? It will be a vitara build?
2. How does the EF chassis do with that much power? How is traction compared to other honda chassis? I had a turbo eg before and it was tons of fun
3. How laggy are the single cam motors and what turbo is best for my power goals?

Thanks

 

I wouldn’t spend all the time and money on swapping a K series, I’d rather spend that money on building a D16Z6. If you were only going for 350-375hp, it would be a lot more reliable with stock sleeves and Vitara pistons.
1. At 400hp, that’s the limit of Vitara pistons, so if you are able to go with something better like Wiseco, C.P., or J.E. , they would be several hundred more dollars, but much more durable. If you do the Vitara pistons your tune must be spot on to hit 400. You’ll also want to look into sleeves or a good block guard like the Cylinder Support System for anything above 400hp.

2. The EF chassis is good, many people have used it with high Hp builds. It’s comparable to the CRX. If you do a K series swap, I think traction might be worse since there is more weight and more torque. The D series has plenty of power for the EF chassis.

3.D series can be laggy with a large turbo, but if you go with a reasonable sized turbo like a T3/TO4E you will be able to reach 400hp without much lag, just a little bit. Power won’t be an issue though because in 1st gear you’ll have more power than you need, and second gear and up lag won’t be very much at all. Just don't go with a huge turbo, and lag isn’t an issue.

 

Not sure about a vitara build, haven't done one. But my Z6 is 400 whp and I've got 12K miles on it and a few drag strip passes. I agree with highschooler - I would do CSS or Chris Boyette epoxy and a forged piston (mine is CSS/CP pistons). Reliability is all in how you build and tune it, and what you consider reliable. I blew 2 head gaskets before I got the setup working like I wanted, but I chalked that up to being part of the learning curve. You're more likely to have cooling issues in the EF chassis, especially if you go with a big top mount manifold. You can talk to @mynameisjustin for his input on keeping a turbo engine in an EF chassis cool. The EF bay is more cramped than the EG bay, but you can make it work.

Regarding traction - honestly you'll likely turn it down on the street some to maintain traction. Boost by gear is highly recommended.

Laggy mostly depends on what turbo you choose. Pick the smallest turbo you can that will meet your power goals, and pick a ball bearing name brand one with the new wheel technology and you'll have good boost response.

 

Thanks for the replies. I do not mind getting better parts in order to make the engine last longer. It is my daily in the summer. For the cost I think I may end up building a single cam. At worst I can always swap in a k down the line. At the end of the day I know I will try to get more power so a good quality build makes sense.

 

400 is the magic number for a D16 where you can get there by just running lots of boost, but youre getting into the range where head sealing can be an issue, and around the power level where sleeves start failing.

The other way to go about it, is to mod the engine as you would NA, port the head, upgrade the springs, and put a cam in it (nothing too wild, just something like a "stage 2" from a good vendor). This way, you can still get to the 400 mark, but without having to run heroic boost. Youll make less torque, and have to rev higher to make the number, but it wont be as hard to keep the headgasket sealed and may not be as hard on the sleeves either.

With either configuration, you will need good rods and pistons. Vitaras work pretty well with the special log rods, but the CR is still a bit on the low side. Stock length rods with Vitaras is not worth it unless youre going for super budget setup with stock B18 LS rods. The CR is just too low and the lack of quench is probably not good either. In my experience the CR is so low that you cant advance the timing far enough without lifting the head (i.e. its not knock limited).


As for your questions about chassis. The EF can be made to put power down just like anything. You gotta put some work into it no matter what it is.
The big problem with D series builds is the unequal length axles and lack of LSD. Makes the car go all over the road with lots of power.
If you want a really good setup, I suggest D2B with a good LSD. I believe there is also a way to stay with a D series trans and have an intermediate shaft if you use a DOHC ZC trans, that would help a lot but an LSD is still really important to put down lots of power.


As for lag, it depends on what you mean. If you want to make lots of boost at low RPM, and still make lots of power, its not happening. If youre talking about actual "lag" though, that comes down to the turbo. With a good turbo you can stab the throttle at 4k rpm and it will spool up with almost zero lag.

 

i think d2b is the best option to go with on a single cam. The b series trans has much better gearing imo. For starters I will be running the stock trans till it goes out. Then I will look into options.

full boost by mid 4k RPM is perfect. I just want something fun on the street that can throw it down on the weekend roll races.

 

The d2b is a good option for durability but it’s not simple or cheap. It’s a good idea to use the stock trans until it goes out, which it might or might not. Depending if you dump the clutch or not, the d series trans should hold a lot. You can also buy a used d series trans as a secondary option and build it. From what I’ve researched the d series trans should hold 4-500hp if pre-loaded and without dumping the clutch. There’s some options out there for stronger gearing and Limited Slip Differentials…
For roll races the trans should be fine.

 

You can run a ZC half shaft with the MFactory ZC LSD and run equal length axles. The ZC half shaft is a hard item to find, but I've picked up one hydro and one cable ZC half shaft in the last 2 years.

I'm still running the unequal length axles and an MFactory D-series LSD and it's held up so far. My stock gear set is holding up fine so far launching on slicks. Shock loading is what breaks these transmissions (D or B) - preloading and getting out of it if you start getting wheel hop are the two things you can do to keep them alive. I personally would not venture down the D2B path, at least until I started breaking D-series transmissions regularly. As stated it's expensive - I've paid less than $100 each for the last 3 D-series transmissions I bought. I don't think I've seen a B-series transmission for under $500 in a while. And the B-series gear sets break just as easily as the D-series ones. MTM is making relatively affordable aftermarket gear sets for D-series transmissions too. But if you're looking for a dog box, D2B is the way to go - there are no D-series dog boxes on the market right now.

 

Is there a source online that sells D series transmissions that you’ve used? I’m considering buying a second transmission. I went to the local pick-and-pull junk yard and I think I saw two manual transmissions, but they were still in the car and I didn’t have any tools with me. Is it better to try a local junk yard, or is there an online vendor that can get D series transmissions?

 

Also, does anyone think the transmission will have problems if he (or I) do roll races and don’t launch the car? Isn’t launching the most damaging thing for transmissions?

 

I've just been watching FB marketplace for the transmissions I'm looking for to become available. Offer what you're willing to pay - some take it and some don't. Or, local pull yard is the next best option.

Shock loading (launching without preload and/or trying to power through wheel hop) are what typically kill our transmissions...up to a point. There is a point where the amount of torque applied (even without shock loading) will begin breaking gears. I'm not sure where that point is, but I think folks typically find it in the 500 whp range for 3rd and 4th gear. You could keep a stock 1-3 gear set and run MTM 3rd and 4th if you wanted to.

 

Im not so sure the B transmissions are even much stronger than D series
The main reason Id want a B series box is for the gear ratios. A D series car would be a lot quicker with GSR or B16 gearing than the EX/SI gearing.

 

Depends on the type of driving you are doing I guess. I feel like the EX gearing is great for drag racing - I can do 140 in 4th (with my current rev limit / tire size) which leaves a lot of room for growth. I'm currently trapping in the low 120's. With a GSR transmission I'd have to shift to 5th to go over 120. The B16 is even shorter with 4th topping out around 110. By the time you're trapping 140+ you're probably already breaking stock gear sets though, regardless of whether you're D-series or B-series. If you're going with aftermarket gears any way, you can pick whatever ratios you want in either platform.

 

Did MFactory have options for different gear ratios for D-series Transmissions? For some reason I always thought they had.

 

Thanks for the info, I’m going to look into the local salvage yards.

I’m interested to know this also, although I’d probably stay with stock gearing for the reason Dax explained, because 4th gear can allow up to 140mph traps at the drag strip.

The Original Poster is now showing as banned (ef n around) so I hope it’s not because of this post. I just did a search and he only had 4 posts that seemed kind of reasonable, but he was new as of September 2021 and maybe he did something wrong.

 

He seemed like a good user, so unless something happened behind the scenes, the only thing I can think of someone banning him for was possibly his opinion in the off topic section.

Don't feel like digging into it any more to find out, but I may actually see for myself here soon too lol.

Edit: I know MFactory makes LSD's for D series, but I don't remember if they have gear sets. I'll look at their website out of curiosity.

 

I just messaged them on their website, but they are closed now, because it only lists 1st, 3rd, and 5th gear for the D16.

 

MTM will make you whatever you want for ratios. You can buy through Whoopee Doo Racing.

 

 

So it looks like MTM is the way to go for a D series gear set since MFactory only makes 1st, 3rd, and 5th gears for the D series transmission. Although I haven’t contacted MTM or Whoopee Doo Racing (the vendor) yet.