i really want to do the ISR and the deckplate mod this summer and was hoping if i can get feedback from the experts who have had the experience with it. just needed to know the disadvantages and advantages. i heard you may lose low-end torque. even actual numbers would be helpful, thanks a lot guys. oh by the way i have a 98 auto 4wd.

 

checkout the tech section and do a search for Dr. Zhivago here to find lots of good info.

here is a link to the tech section with the isr mods in it.

ohh-yeah i recomand doing the deckp[late mod elbow removal and the isr mod together, i have the elbow and isr mods done on my tacoma and it is very noticable the "power" increase gained from it.

my .02

john

 

This should just about cover all your questions.

 

Hey there,

Advantages -

Easily reversible.
Definite Power Gains. (See this thread)
No loss of low end torque, quite the opposite, in fact.
Sounds powerful and throaty.
Best bang for the buck mod on a N/A truck.

Disadvantages -

May be too loud for some.
I really can't think of any other disadvantages than the noise increase. If you do it wth the deckplate, it's a lot louder than if you do it with the elbow removed. The DP/ISR mod combo is the largest power increase.
Oh, it may require the use of 89 or better Octane.

Here are some performance numbers gathered by 96 Runner showing before/after results:



As you can see, it does make a noticeable difference in performance.

Hope this helps.
Dr. Z

 

Even the noise increase isn't *that* bad. At highway speeds and if you drive calmly, it's actually quieter in some cases. Now if you get on the gas, then it wakes up and says hi, but personally I think it's cool...

I can't wait until I can toss some headers and better flowing exhaust on there to round out the whole package!

 

My question is do you HAVE to run premium gas? Cuz I'm cheap and can't pay for premium gas lol. Next is, is there an affect on MPG? If the answer to all these questions are no, then Christian wanna help me

 

Prem fuel kinda depends on the condition of your engine. When Toyota assembled your engine, they followed SPC (Statistical Process Control) which allows certain specs and tolerances to vary from engine to engine (within a certain range of course).

So, it really depends. The way I see it is this: The mod is so easy to reverse that its worth it. For long trips you can put it back to stock in about 5 minutes, and run Reg Unleaded again. I run premium because my truck pings on Reg with this mod. Also, Costco premium is the same or cheaper than Reg gas at the other stations. So, its "free" power if you ask me.

I say do it! And of course I can help you.

 

what is the elbow mod and what is the total cost (ball-park) of this mod?

 

Check it out in the Tech section.
Just to make it easier for you follow this link

Your cost?
Just a few calories



A few comments on the ISR:
I really think you need to do this WITH the elbow or deckplate mod as I have neither and it's harder to notice the power gains.

Fuel - well, I had been running 87 octane for the first few tanks after the mod and didn't notice pinging or anything but the first tank of premium I did notice that my performance upped a little. According to Christian <96> and Galen (Dr. Z), if you don't have pinging the type of fuel doesn't matter. Correct me if I'm wrong you guys? I guess it's just whether or not you want the extra power.

Noise - I have noticed that it's a little quieter on the freeways. Once I hit a steady speed and the RPMs settle at a little over 2K, I can talk on my mobile phone with my girlfriend who tends to be softspoken sometimes. However, when I'm going somewhere in a rush the roar is noticeable. I like it!
I tend not to do too much speeding and hadn't discovered the louder engine roar at higher RPMs until just recently.

Just what I've noticed. Sorry, no numbers...

 

96 Runner,

I noticed you have your FPR and PWR steering pump(i think) vacuum lines attached to the plumbing end cap. Did this endcap have the tits already on it or did you customize it to accomidate these vacuum lines?

I am currently running all the vacuum lines off the plenum one with a series of T connectors. I would like to attach mine like you have because I noticed some strange behavior from my rig while driving on the highway this weekend.
I was using cruise control and noticed upon a downshift into third gear (auto tranny of course) the RPMS would jump up higher, like they would under any normal dwn shift, but would immediatley die down about 400 RPMs and then start to gradually increase with speed. I noticed this a few times with the cruise control on and another time while using the traditional foot on gas pedal method. I'm pretty certain I need to reconnect those vacuum lines to the intake hose.

Sorry for stomping on your thread Amir 904. For the price you need to try these mods. Like Dr. Z said, they are both easily reversable.
-Tim

 

TSTango:

I had the same problem with mine just recently. Unfortuntely, I was never able to find a solid cap so I went with some cap that had a 1 1/2" opening in which I placed a rubber grommet (<96>, sorry if I got the notation wrong, I know that's a pet peeve of yours. I can never seem to remember which is which ).

After running into the same probles I did a lot of hunting and ended up with a grommet and vaccuum tubing that fit it perfectly. I tucked it into the cap with a considerable amount of silicon sealant and secured the tube to the FPR line with a tube bracket thingy.

I didn't notice that much of a difference until I ran premium. I think I'll stay with premium.

 

Tim-

I JB-welded a couple "male" fittings (hollow) to the plumbing end- cap. I tried to maintain the same vacuum line diameter and length if possible.

You may want to give this a shot. I remember messing with the really long vacuum line that goes across the entire engine bay (from the right to the left) on my Tacoma, and I got a CEL.

So, try and get your set-up like mine if you can.

 

THanks guys.

I'll have to get crafty on this one

 

Just a couple of quick comments to add to all the other good info here. I'd suggest just doing the deckplate and ISR, leave the elbow alone. Gadget showed that there wasn't any real advantage to doing both at the same time (ie. the gains with the deckplate was the same as the deckplate and elbow removed). The elbow is much harder to reverse, and if you go off-roading you run the risk of getting water in the intake- the deckplate can easily be sealed back up. Secondly, as far as the vacuum line, (I have a 98 4wd as well), I think Dr. Z ended up just capping it off, and noticed a bit of a boost from just that. This eliminates the need to try to jerry- rig new fittings to the plumbing endcaps. I bought a vacuum cap, capped it off, and have not run into any troubles. Thirdly, as far as pinging, it does seem to be a bit vehicle specific. I have the deckplate, ISR removed, with K&N filter, and I haven't had any pinging (at least that I can hear anyways) with 87 octane.

Good luck modding!

 

I found just the opposite when capping the FPR line off. Check out the link I put in the thread above. I lost performance when I capped it off, primarilly because I dont have the tunability that Dr Z has, and my test method runs just about the whole rev range, instead of say the 1/4 mile, where shifts will all take place in the upper rev range. My vote is uncapped (line hooked up to the FPR).

Anyway, you can do what you want. But, I thought I would mention this. In fact, we may have discussed it before Mad Chemist...

 

I run 85-oct fuel (granted, at Denver altitude) with no pinging at least that I have noticed.

Remember - higher octane DOES NOT give you more power! It causes the fuel to burn more slowly, which is needed on high compression engines or engines with forced induction. You will notice a power increase if the low grade gas isn't working out for you and is causing inefficient combustion.

I'd imagine if you see pinging with low-grade gas, try the mid stuff (87 or 89 depending on where you are) and see what happens. I have a hard time believing you need premium with just the ISR and deckplate, on a normally aspirated engine; you are increasing the rate of airflow into the engine, but you're not adding boost and I don't see how the compression would be high enough on these engines to warrant premium gas.

Just my $0.02.

 

Denverbikeguy-

Costco sells 87 or 91. No in-between. So, naturally I choose the 91 octane.

I agree with what you said about higher octane burning slower, etc. But, we also have to remember that we are screwing with the FPR line, which can lean out the air/fuel ratio in certain instances. Whereas the FPR line capped causes a rich condition at low RPM's, also "hurting" performance.

So, by running premium, we reduce the pinging because the FPR line uncapped caused a lean condition with reg fuel.

Another factor is the knock sensor. Some may be running the ISR mod, uncapped, with Reg Fuel, and the knock sensor is doing its job, retarding the timing. Hence a loss in performance, instead of a gain.

Its really hard to say without a stoich meter. Just throwing some ideas out there...

 

Crap, I do remember talking about pinging with you, but I didn't catch the difference between capped and uncapped! Something else to put on the list to do!

 

Don't know if anyone's interested but I have a length of muffler pipe ready for this mod (extended on the ends and everything) if anyone wants it. Just get me shipping (US Priority $4)

Most likely will be cheaper to find a neighborhood shop w/ scraps but I have this laying around and just thought I'd offer.

 

What do you mean by extended on the ends? I might be interested.