difficult decision

[91_bowtie]

I've decided to get rid of the 22's and put the cash towards a 6.0 or an intercooler setup. I'd really like a new motor, but I think I need an IC; especially now that I'm at 10 psi. The meth is doing a great job on keeping things cool once I build 5 psi, but just cruising along, it heats up quick. It cools down pretty quick too though. On the other hand, I'd love to have a 6.0 under the hood. Do I need anything for the swap? I'm guessing that I'll have to step up to the 60# injectors? What would you do? I could always just hang onto it and wait for the next part to break, but that's no fun.

[misterp]

IMO don't bother with the LQ4/LQ9 unless you are given one for free; if you are going to go to all the trouble and expense of swapping motors make it worth your while and install an engine with a 4" stroke to get that wagon moving off the line. My 2-cents...

Mr. P.

[docone882000]

TRT is doing some nice stroker motors for the price. You may want to check into one of those. You will get a lot more bang for your buck.

[DBYRD]

6.0 is the way to go. with the low compression lq4 u can turn that boost up, and the extra displacement just adds to what u already have. theres no substitute for displacement, and the way the 6.0's r going might as well just swap it straight in. idk a cheaper way to gain hp, maybe a tune but thats it. u can find 6.0's for less than 2 grand, idk what else u could add for less than that with that big of an upside.

[misterp]

I guess the real question is - what exactly are your performance goals, both short and long term?

re boosting an LQ4 more than an LQ9, I half-agree; yes the LQ4 looks more attractive with it's lower CR, but you cannot put much more boost into it (over an LQ9) not because of threat of detonation but because you risk busting the ring lands of the factory pistons; those hypereutectic slugs are only going to take so much cylinder pressure, failures are seen starting in the 550hp range, and that can easily be done with 8+ lbs on a LQ9.

I do agree with Allstar that a more affordable option might be to find a running core LQ4 provided you have it rebuilt with forged pistons & ARP rod bolts (use the OEM crank & rods). The LQ4/LQ9 crank is ungodly strong and you'll have forged pistons so later (after you've gotten an intercooler hint hint) you can ramp up the boost, and since you are maintaining the factory stroke I wouldn't imagine seeing a strength problem with the factory rods regularly shifting at 6600rpm, which with an A4 will be about the realistic upper limit anyways, you'll probably have a lot lower shift point (6200-ish???) unless you have already installed a hi-rev kit in your tranny.

The question is how much boost are you planning on running in the future? If you are using the FI kit you have now (I've got no idea what you have btw) you might not need the mototron 60's, the SVO 50-lb injectors might be a bit better sized for your needs. That's just a wild-assed guess, again I've got no idea what you've got in mind...

Mr. P.

[91_bowtie]

<div class='quotetop'>QUOTE(Mister P &#064; Nov 21 2006, 02&#58;31 AM) [snapback]74074[/snapback]</div>

I guess the real question is - what exactly are your performance goals, both short and long term?

re boosting an LQ4 more than an LQ9, I half-agree; yes the LQ4 looks more attractive with it&#39;s lower CR, but you cannot put much more boost into it (over an LQ9) not because of threat of detonation but because you risk busting the ring lands of the factory pistons; those hypereutectic slugs are only going to take so much cylinder pressure, failures are seen starting in the 550hp range, and that can easily be done with 8+ lbs on a LQ9.

I do agree with Allstar that a more affordable option might be to find a running core LQ4 provided you have it rebuilt with forged pistons & ARP rod bolts (use the OEM crank & rods). The LQ4/LQ9 crank is ungodly strong and you&#39;ll have forged pistons so later (after you&#39;ve gotten an intercooler hint hint) you can ramp up the boost, and since you are maintaining the factory stroke I wouldn&#39;t imagine seeing a strength problem with the factory rods regularly shifting at 6600rpm, which with an A4 will be about the realistic upper limit anyways, you&#39;ll probably have a lot lower shift point (6200-ish???) unless you have already installed a hi-rev kit in your tranny.

The question is how much boost are you planning on running in the future? If you are using the FI kit you have now (I&#39;ve got no idea what you have btw) you might not need the mototron 60&#39;s, the SVO 50-lb injectors might be a bit better sized for your needs. That&#39;s just a wild-assed guess, again I&#39;ve got no idea what you&#39;ve got in mind...

Mr. P.
[/b]

Long term, I&#39;d like to be in the low 11&#39;s. Until then, I&#39;ll settle for mid 12&#39;s. I know I won&#39;t get there on the lq4 swap alone, but a 75 shot should get me close. My current cam is a 220/224 .564/.567 on a 115 LSA, so it should do well in the 6.0. I think the only thing I&#39;d really have to upgrade would be the fuel system and exhaust.

Current mods are shown here... HERE The only updates are 10 psi and e-fans. I&#39;m running the smallest pulley that whipple makes, so I&#39;ll have to have one made. I&#39;d like to see 15 psi eventually.

[misterp]

<div class='quotetop'>QUOTE(91_bowtie &#064; Nov 22 2006, 01&#58;14 AM) [snapback]74220[/snapback]</div>

Long term, I&#39;d like to be in the low 11&#39;s. Until then, I&#39;ll settle for mid 12&#39;s. I know I won&#39;t get there on the lq4 swap alone, but a 75 shot should get me close. My current cam is a 220/224 .564/.567 on a 115 LSA, so it should do well in the 6.0. I think the only thing I&#39;d really have to upgrade would be the fuel system and exhaust.

Current mods are shown here... HERE The only updates are 10 psi and e-fans. I&#39;m running the smallest pulley that whipple makes, so I&#39;ll have to have one made. I&#39;d like to see 15 psi eventually.
[/b]

We have similar performance goals, and your Tahoe weighs very nearly the same as my SS. Several guys in the SSS crowd have taken the stock LQ9 and gotten their trucks into the mid-11s with very careful preparation. You&#39;ve already got a lot of good work in your Tahoe that can be carried over onto a LQ4/LQ9. If it were my project I would seriously consider the forged-piston LQ4, that would allow you to get the boost up to a level you&#39;d be a lot more happy with. Again my 2-cents.

Mr. P.