Interest in Bolt on Turbo kit?

[MikeW]

based on the WRX results the virtual dyno app I am using estimates low numbers. It could be the street because the app calibrates friction loss after you accelerate, so if there is a slight change in slope over the course this could bias the results up or down. I ran the WRX and M42T on the exact same street, at the same starting point. So based on the WRX results we appear to be 10 to 20 hp low.

Regardless, it's a hell of an improvement and the shape of the curve is going to be very accurate, regardless of power levels. The torque curve hits perfect for a DD in my opinion..

[dpmcdonald]

based on the WRX results the virtual dyno app I am using estimates low numbers. It could be the street because the app calibrates friction loss after you accelerate, so if there is a slight change in slope over the course this could bias the results up or down. I ran the WRX and M42T on the exact same street, at the same starting point. So based on the WRX results we appear to be 10 to 20 hp low.

Regardless, it's a hell of an improvement and the shape of the curve is going to be very accurate, regardless of power levels. The torque curve hits perfect for a DD in my opinion..

Actual dyno or not, it's great data regardless and I thank you for your time in collecting and putting it together! This should be solid confirmation for anyone who is still on the fence about ordering this kit.

Order the kit people!

[dpmcdonald]

Interest in Bolt on Turbo kit?

My buddy's e21 that we designed the tune on was over boosting for a bit when he has the wastegate preload set wrong. He was around 14psi for awhile and it held. He did dial it back to 9psi just to be sure.



This is on an m42 with around 160k on it and the clutch that came with the engine. Now...who knows if it is stock or how many miles are on it. But he thrashes it pretty good.



So ARPs..a good clutch. m20 would be good...and go to 15psi it will be happy. We might need to tweek the tune some.

Interesting. The pistons are the weakest link, yes? I wonder what would be a "safe" level of boost with ARP studs and a nice tune on a MAF—15psi? Or would it just be a ticking time bomb?

[Leo1234]

would this bolt on turbine work for the same m42 auto? asking bc a friend is interested in the kit

[MikeW]

It would work fine, not sure your transmission would last very long.

[jakeb]

would this bolt on turbine work for the same m42 auto? asking bc a friend is interested in the kit

I assume that would be in an e36?

[wazzu70]

Interesting. The pistons are the weakest link, yes? I wonder what would be a "safe" level of boost with ARP studs and a nice tune on a MAF—15psi? Or would it just be a ticking time bomb?

The pistons can sustain the power with a good tune although they will be much more easily damaged by detonation so you have to keep the timing safe. You would also want to regap the rings if the pistons are out to help them deal with the heat.

Assuming your tune is decent so you arent hammering the snot out of the pistons, the rods are the weakest link.

Forged pistons have a lot of advantages though as you can set the ring spacing different, increase crown thickness, change compression, ect. Just because stockers can work does not mean its the best path...its the best cheap path.

[dpmcdonald]

The pistons can sustain the power with a good tune although they will be much more easily damaged by detonation so you have to keep the timing safe. You would also want to regap the rings if the pistons are out to help them deal with the heat.



Assuming your tune is decent so you arent hammering the snot out of the pistons, the rods are the weakest link.



Forged pistons have a lot of advantages though as you can set the ring spacing different, increase crown thickness, change compression, ect. Just because stockers can work does not mean its the best path...its the best cheap path.

Hmm.. I read somewhere that the M42 stock crank and rods are forged, but the pistons are cast. Hence, why I figured they were the weak link.

Anyway, that doesn't make your statement any less true. I plan on running stock pistons until they need replacing and I'm trying to guage how much boost I can get away with (for 20k or so miles) on Jake's MAF tune. What scares me the most is the lack of a knock sensor in these cars! I've been doing a little searching around the interwebz to see what others have done with 10:1 CR and the highest (on a street car) I've seen anyone admit to was 15psi, but that was on 93 octane and we only get 91 here in Portland, OR. So, I'm thinking my target should be about 12psi.

Thoughts?

[wazzu70]

PSI really does not have anything to do with it. Different turbos move the same CFM at different PSI/pressure. What you really need to determine the weak link is peak torque which is related to combustion cylinder pressure.

If you dont have the ability to tune yourself, you can always listen to the engine using "det cans" which is way better than a generic knock sensor. Your brain processes the signals pretty darn well and you dont need to program a knock box. Look up det cans online and you will see how to make the cheap and easily. Use these to determine how much max pressure you can target with your particular tune/fuel octane.

Im in WA so we have only 91 too :(

[dpmcdonald]

PSI really does not have anything to do with it. Different turbos move the same CFM at different PSI/pressure. What you really need to determine the weak link is peak torque which is related to combustion cylinder pressure.



If you dont have the ability to tune yourself, you can always listen to the engine using "det cans" which is way better than a generic knock sensor. Your brain processes the signals pretty darn well and you dont need to program a knock box. Look up det cans online and you will see how to make the cheap and easily. Use these to determine how much max pressure you can target with your particular tune/fuel octane.



Im in WA so we have only 91 too :(

Awesome! Thanks for the guidance!

[brads2002]

Can the headbolts be replaced with out removing the head or damaging the existing seal? Wonder what would happen if you did them one at a time.

[16v_e30]

Can the headbolts be replaced with out removing the head or damaging the existing seal? Wonder what would happen if you did them one at a time.

There's a specific torque sequence which needs to be followed for the head studs. You cannot follow this sequence unless you have all the new hardware in place at the same time.

Can you install them without removing the head? Yes. Probability of head gasket failure? High.

It's really not all that difficult to remove the head, I would just do that and play it safe with a new HG.

[16v_e30]

Oh, and I actually have one of Jake's kits, and installed head studs as well, with all new gaskets. I haven't driven it much because I have oil leak problems, and I was still breaking in the clutch, but it drives AWESOME. I also have a 2004 wrx with a 20g turbo, and the m42T is much more driveable. There's torque everywhere and it feels super smooth. I wasn't going to chime in until I've had the full experience, but I figured I'd share what I had. Build quality on all the parts were very high, and Jake was more than very highly helpful in the process, and very quick to return emails.

[whodwho]

Can the headbolts be replaced with out removing the head or damaging the existing seal? Wonder what would happen if you did them one at a time.

This can be done, it was common practice at the dealer when there was an issue with headbolts on the M20.

You remove, replace and torque them one at a time, you can do them in the order of the torque sequencebut not sure that really matters. But it is best to blow out each hole before putting a new headbolt/stud so there is no oil or you can crack the block.

[brads2002]

Good call on the m20. I actually did a few of those several years back. I remember going from hex to torq heads. Thanks forgot all about it. One. At a time to the specific stretch torque.