Reasons NOT TO choose a particular FI kit...
 

Hi all,

I've read & re-read a TON of info on the various FI kits for our cars (thanks to all the guys for their great input and research!) so I don't want to rehash those threads and get told I should go with other options like KW over JR.

I've narrowed it down to the following;
1. I want a SC for ease of use, ease of install and overall simplicity of creating more power (i.e. no turbo) + the power these kits make suits my needs just fine.

2. I already have headers and a flexfuel kit on the car (woohoo)

3. I've narrowed down my FI choices to 2 main options, the Jackson Racing centrifugal/Rotrex kit or the Sprintex/Innovate 210+ kit.

I do not mind revving the car to 7k to access the power, but I also see the benefits of the twin screw kick in power lower down. However, as I am after longevity and reliability I think the Rotrex kit is "kinder" to the engine as it builds the power more steadily (but I could be wrong).
The reason for these 2 options is because I like the Rotrex kits and Jackson has great reviews overall + a fair price.
Sprintex is readily available here.

All other kits had downsides I didn't think were worth it (e.g. the Edlebrock kit is more expensive and heavier, the Cosworth kit is priced like I drive a Ferrari, and ultimately they all make between 250-300whp depending on who dyno'd them and what supporting mods you have).

I have some questions, but please can only those with experience of these kits give their comments ;

My main question if you own either kit is... is there any reason why I should not get your kit?

Is there any reason you'd say definitely buy A or B kit?

Finally - I live in a fairly warm climate which is also why I'm looking at going the Rotrex route (less heat generally).


Thanks in advance!

So one thing about the JSRC is that it actually creates a lot of heat. Many of the guys in my group always complain about overheating issues while on the track. One member actually cracked his stock headers due to that reason. Not saying its a deal-breaker but something to consider since you are in a warmer climate.

You mentioned reliability as a big factor for you. Honestly i would highly recommend the Edelbrock. While on paper it may seem like its a recipe for disaster especially in your climate, the Edelbrock consistently had cooler temps than my friends JSRC. And while that was due to mainly Daily Driving it still says a lot about the kit. After a hour long drive i'm actually able to put my hand right on the kit and not melt it off. Edelbrock is also arguably the most reliable kit out there.

One of the major downsides to the Edelbrock (and largely why i got rid of the kit) IS the weight that you mentioned. You can feel the extra height and weight affect the engine. While for some its no big deal, it bothered the hell out of me. I'm also a turbo guy =D.

This kit is also more for DD as most of the power is in the mid range. If you prefer to drive it past 6k RPM normally then i think a JSRC would be better suited for you. But just keep in mind the heat.

A low COG alternative to the Edelbrock is the Harrop SC. It's more compact, uses the same compressor unit, and can match the power output.

Positive displacement SC do have the downside of loading the notoriously week piston rods with stress early in the powerband, but so long as you're not set to drag race the car you should be fine.

When I did my comparison of the different PD SC out there, the innovate kits have the unfortunate issue of only offering an undersized compressor for the engine or oversized compressor, requiring an oversized pulley to keep from needing a built engine.

Good call on the Harrop. I believe that one is also developed in Australia so you KNOW they had heat in mind.

I installed JRSC myself. It fits and looks like OEM equipment. Heat is not a problem in my daily driving even in the hottest days with OEM STI oil cooler. The carb tune is very smooth and efficient. My car drives like OEM. Normal driving has absolutely zero mpg penalty due to supercharger. The power delivery is very smooth and linear. It is very easy to drive daily but, above 5000 rpm, power is unbelievable compared to stock car.

On the track, JR oil cooler is a must. That is what Oscar Jackson Jr uses on the track. He won the SCCA title last year with that setup. Also checkout the speed academy videos on youtube. They won Ontario 1500 with JRSC and oil cooler. I didn't see anything that was tested better than JRSC on the track. That is why I chose it and there has been zero problems since 3000 miles. My only regret is not installing earlier.

Good info in this thread. Also interested.

If you are doing this for the fun of driving and not worried about being the fastest guy on the block. Then the sprintex is a good choice as the 210 will not tax the engine greatly. I got one of the first in the US and have been running it ever since. I do use the car on the track for fun and did not have over heating problems (even as stock). It does need a cooler for serious use.
For long life with little maintenance the twin screw is a great choice.
If going fast is the end then turbo is the answer, I run them when serious on the track (or large displacement works well.)

You're RHD in SA aren't you? Edelbrock kit is designed for LHD and needs modification. It also might only make sense financially if you live in the States. The Harrop is cheaper here in the UK.

How will it be tuned!?!?

Local support is the difference here imo, if you get in over your head with something, what's your backup plan? Local tune? Off the shelf tune?

The best specs in the world won't matter if you there's an error you cannot diagnose and correct. If you're going with a tuner who isn't local to you ask for their recommendation. If you have a local tuner who will be working with you ask for what they believe they have the most confidence in supporting you with.

Why no mention of Vortech kit??

Because the Vortech is inferior to Rotrex kits.

How? Please explain


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You're throwing out whataboutism but didn't add to the discussion. Maybe you should tell us why it's a good or bad SC for OP.

The only thing that a Vortech unit has going for it is that it is less expensive. Vortech units are larger than Rotrex units. So, packaging wise it is easier to install a Rotrex unit especially where space is a commodity. You can run a Rotrex off different size pulleys for different PSI depending how built your engine is. But this next quote pretty much sums it up for the BRZ, FRS, 86 as to why the Vortech is inferior for our platform:

"a s/c has to be matched to an engine to use the most optimal range of its efficiency. there is an area beneath the vortech's operating range at which the drag of the charger is more detrimental than it superior maximum flow potential (which may very well go unused). The goal is to keep the blower in its optimal range of efficiency, for a smaller motor, seeing much lower revs, rotrex is way more effective. This is so due to the rotrex's outrageous efficiency at lower cfms. The vortech becomes bulky, unnecessary, and parasitic at these lower cfms."

And from the SC compilation thread:

Post #1
http://www.ft86club.com/forums/showthread.php?t=55705

"These charts also make it clear that the Vortech's powerband is 5-15% inferior to the Rotrex powerbands from 4000-7000 RPM."

There's a lot more useful information in that thread to make an informed decision on what SC kit to purchase. But from the 2 choices the OP is considering the JRSC kit beats the Innovate kits hands down especially in the higher RPM ranges.